\input texinfo.tex @c -*-texinfo-*- @setfilename texinfo.info @c Automake automatically updates version.texi to @set VERSION and @c @set UPDATED to appropriate values. @include version.texi @settitle GNU Texinfo @value{VERSION} @c Define a new index for command-line options. @defcodeindex op @c Put everything except function (command, in this case) names in one @c index (arbitrarily chosen to be the concept index). @syncodeindex op cp @syncodeindex vr cp @syncodeindex pg cp @c finalout @c flag to index command names without extra text in the entry @ifinfo @set commandlookup @end ifinfo @ifhtml @set commandlookup @end ifhtml @microtype on @copying This manual is for GNU Texinfo (version @value{VERSION}, @value{UPDATED}), a documentation system that can produce both online information and a printed manual from a single source using semantic markup. Copyright @copyright{} 1988-2023 Free Software Foundation, Inc. @quotation Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled ``GNU Free Documentation License''. @end quotation @end copying @dircategory Texinfo documentation system @direntry * Texinfo: (texinfo). The GNU documentation format. * install-info: (texinfo)Invoking install-info. Update info/dir entries. * texi2any: (texinfo)Invoking texi2any. Translate Texinfo source. * makeinfo: (texinfo)Invoking texi2any. Translate Texinfo source. * pod2texi: (pod2texi)Invoking pod2texi. Translate Perl Pod to Texinfo. * texi2dvi: (texinfo)Format with texi2dvi. Print Texinfo documents. * texi2pdf: (texinfo)PDF Output. PDF output for Texinfo. * pdftexi2dvi: (texinfo)PDF Output. PDF output for Texinfo. * texindex: (texinfo)Format with tex/texindex. Sort Texinfo index files. @end direntry @set txiindexatsignignore @set txiindexbackslashignore @set txiindexlessthanignore @set txiindexhyphenignore @clear txicodevaristt @titlepage @title Texinfo @subtitle The GNU Documentation Format @subtitle for Texinfo version @value{VERSION}, @value{UPDATED} @author Robert J. Chassell @author Richard M. Stallman @page @vskip 0pt plus 1filll @insertcopying @sp 1 Published by the Free Software Foundation @* 51 Franklin St, Fifth Floor @* Boston, MA 02110-1301 @* USA @* ISBN 1-882114-67-1 @c for version 4.0, September 1999. @c ISBN 1-882114-65-5 is for version 3.12, March 1998. @c ISBN 1-882114-64-7 is for edition 2.24 of November 1996. @c ISBN 1-882114-63-9 is for edition 2.20 of 28 February 1995. @ignore @sp 1 Cover art by Etienne Suvasa. @end ignore @end titlepage @summarycontents @contents @node Top @top Texinfo This manual is for GNU Texinfo (version @value{VERSION}, @value{UPDATED}), a documentation system that can produce both online information and a printed manual from a single source using semantic markup. @ifinfo The first part of this master menu lists the major nodes in this Info document, including the @@-command and concept indices. The rest of the menu lists all the lower-level nodes in the document. @end ifinfo @node Copying Conditions @nodedescription Your rights. @unnumbered Texinfo Copying Conditions @cindex Copying conditions @cindex Conditions for copying Texinfo @cindex Free software @cindex Libre software GNU Texinfo is @dfn{free software}; this means that everyone is free to use it and free to redistribute it on certain conditions. Texinfo is not in the public domain; it is copyrighted and there are restrictions on its distribution, but these restrictions are designed to permit everything that a good cooperating citizen would want to do. What is not allowed is to try to prevent others from further sharing any version of Texinfo that they might get from you. Specifically, we want to make sure that you have the right to give away copies of the programs that relate to Texinfo, that you receive source code or else can get it if you want it, that you can change these programs or use pieces of them in new free programs, and that you know you can do these things. To make sure that everyone has such rights, we have to forbid you to deprive anyone else of these rights. For example, if you distribute copies of the Texinfo related programs, you must give the recipients all the rights that you have. You must make sure that they, too, receive or can get the source code. And you must tell them their rights. Also, for our own protection, we must make certain that everyone finds out that there is no warranty for the programs that relate to Texinfo. If these programs are modified by someone else and passed on, we want their recipients to know that what they have is not what we distributed, so that any problems introduced by others will not reflect on our reputation. The precise conditions of the licenses for the programs currently being distributed that relate to Texinfo are found in the General Public Licenses that accompany them. This manual is covered by the GNU Free Documentation License (@pxref{GNU Free Documentation License}). @node Overview @nodedescription Texinfo in brief. @chapter Overview of Texinfo @cindex Overview of Texinfo @cindex Texinfo overview @cindex Using Texinfo in general @cindex Texinfo, introduction to @cindex Introduction to Texinfo @anchor{Using Texinfo} @c merged node @dfn{Texinfo} is a documentation system that uses a single source file to produce both online information and printed output. This means that instead of writing several different documents, one for each output format, you need only write one document. Using Texinfo, you can create a printed document (via the @TeX{} typesetting system) in PDF format, including chapters, sections, cross-references, and indices. From the same Texinfo source file, you can create HTML output suitable for use with a web browser, you can create an Info file for use in GNU Emacs or other Info-reading programs, and also create DocBook, EPUB 3, or @LaTeX{} files. @cindex Source file format @cindex Semantic markup A Texinfo source file is a plain text file containing text interspersed with @dfn{@@-commands} (words preceded by an @samp{@@}) that tell the Texinfo processors what to do. Texinfo's markup commands are almost entirely @dfn{semantic}; that is, they specify the intended meaning of text in the document, rather than physical formatting instructions. GNU Emacs has a special mode, called Texinfo mode, that provides various Texinfo-related features. (@xref{Texinfo Mode}.) @cindex Limited scope of Texinfo Texinfo was devised specifically for the purpose of writing software documentation and manuals. If you want to write a good manual for your program, Texinfo has many features which we hope will make your job easier. However, Texinfo is not intended to be a general-purpose formatting program. It provides almost no commands for controlling the final formatting, so may be inappropriate for your needs if you want to lay out a newspaper, devise a glossy magazine ad, or follow the exact formatting requirements of a publishing house. @cindex Spelling of Texinfo @cindex Pronunciation of Texinfo Spell ``Texinfo'' with a capital ``T'' and the other letters in lowercase. The first syllable of ``Texinfo'' is pronounced like ``speck'', not ``hex''. This odd pronunciation is derived from the pronunciation of @TeX{}. Pronounce @TeX{} as if the @samp{X} were the last sound in the name `Bach'. In the word @TeX{}, the @samp{X} is, rather than the English letter ``ex'', actually the Greek letter ``chi''. Texinfo is the official documentation format of the GNU project. More information, including manuals for GNU packages, is available at the @uref{http://www.gnu.org/doc/, GNU documentation web page}. @node Reporting Bugs @nodedescription Submitting effective bug reports. @section Reporting Bugs @cindex Bugs, reporting @cindex Suggestions for Texinfo, making @cindex Reporting bugs We welcome bug reports and suggestions for any aspect of the Texinfo system: programs, documentation, installation, etc. Please email them to @email{bug-texinfo@@gnu.org}. You can get the latest version of Texinfo via its home page, @uref{http://www.gnu.org/software/texinfo}. @cindex Checklist for bug reports For bug reports, please include enough information for the maintainers to reproduce the problem. Generally speaking, that means: @itemize @bullet @item The version number of Texinfo and the program(s) or manual(s) involved. @item The contents of any input files necessary to reproduce the bug. @item Precisely how you ran any program(s) involved. @item A description of the problem and samples of any erroneous output. @item Hardware and operating system names and versions. @item Anything else that you think would be helpful. @end itemize When in doubt whether something is needed or not, include it. It's better to include too much than to leave out something important. It is critical to send an actual input file that reproduces the problem. Any problems with the Info reader in Emacs should be reported to the Emacs developers: see @ref{Bugs,,, emacs, The GNU Emacs Manual}. @cindex Patches, contributing Patches are welcome; if possible, please make them with @samp{@w{diff -c}}, @samp{@w{diff -u}} (@pxref{,,, diffutils, Comparing and Merging Files}), or @samp{git diff} and include @file{ChangeLog} entries (@pxref{Change Log,,, standards, GNU Coding Standards}), and follow the existing coding style. @node Output Formats @nodedescription Overview of the supported output formats. @section Output Formats @cindex Output formats @cindex Back-end output formats Here is an overview of the output formats currently supported by Texinfo. @table @asis @cindex Info output, overview @item Info (Generated via @command{texi2any}.) Info format is mostly a plain text transliteration of the Texinfo source. It adds a few control characters to provide navigational information for cross-references, indices, and so on. The Emacs Info subsystem (@pxref{Top,,, info, Info}), and the standalone @command{info} program (@pxref{Top,,, info-stnd, GNU Info}), among others, can read these files. @xref{Info Files}, and @ref{Creating and Installing Info Files}. @cindex Plain text output, overview @item Plain text (Generated via @command{texi2any --plaintext}.) This is almost the same as Info output with the navigational control characters are omitted. @cindex HTML output, overview @item HTML @c @cindex Mozilla @c @cindex Lynx @c @cindex Emacs-W3 (Generated via @command{texi2any --html}.) HTML, standing for Hyper Text Markup Language, is the language for writing documents on the World Wide Web. Web browsers @c such as Mozilla, Lynx, and Emacs-W3 can render this language online. There are many versions of HTML, both different standards and browser-specific variations. @command{texi2any} uses a subset of the language that can be interpreted by any common browser, intentionally not using many newer or less widely-supported tags. Although the native output is thus rather plain, it can be customized at various levels, if desired. @xref{Generating HTML}. @cindex EPUB 3 output, overview @item EPUB 3 (Generated via @command{texi2any --epub3}.) EPUB is a format designed for reading electronic books on portable devices. It is a derivative of HTML@. The format was developed by the International Digital Publishing Forum (IDPF), which is now part of the World Wide Web Consortium (W3C)@. The latest major revision, EPUB 3, dates from 2011. @cindex DVI output, overview @pindex dvips @r{(program)} @pindex xdvi @item DVI (Generated via @command{texi2dvi}.) The DeVIce Independent binary format is output by the @TeX{} typesetting program (@uref{http://tug.org}). This is then read by a DVI `driver', which knows the actual device-specific commands that can be viewed or printed, notably Dvips for translation to PostScript (@pxref{Top,,, dvips, Dvips}) and Xdvi for viewing on an X display (@uref{http://sourceforge.net/projects/xdvi/}). @xref{Hardcopy with @TeX{}}. (Be aware that the Texinfo language is very different from @TeX{}'s usual languages: plain @TeX{}, @LaTeX{}, Con@TeX{}t, etc.) @cindex PostScript output, overview @item PostScript (Generated via @command{texi2dvi --ps}.) PostScript is a page description language that became widely used around 1985 and is still used today. @uref{https://en.wikipedia.org/wiki/PostScript} gives a basic description and more preferences. By default, Texinfo uses the @command{dvips} program to convert @TeX{}'s DVI output to PostScript. @xref{Top,,, dvips, Dvips}. @cindex PDF output, overview @cindex Beebe, Nelson @item PDF (Generated via @command{texi2dvi --pdf} or @command{texi2pdf}.) This format was developed by Adobe Systems for portable document interchange, based on their previous PostScript language. It can represent the exact appearance of a document, including fonts and graphics, and supporting arbitrary scaling. It is intended to be platform-independent and easily viewable, among other design goals; @uref{https://en.wikipedia.org/wiki/Portable_Document_Format} and @uref{http://tug.org/TUGboat/tb22-3/tb72beebe-pdf.pdf} have some background. By default, Texinfo uses the @command{pdftex} program, an extension of @TeX{}, to output PDF; see @uref{http://tug.org/applications/pdftex}. @xref{PDF Output}. @cindex LaTeX output, overview @item @LaTeX{} (Generated via @command{texi2any --latex}.) This is a typesetting system built on top of @TeX{}. It was originally released by Leslie Lamport in 1984. @LaTeX{} adds more definitions to those of @TeX{} and has a wide range of packages built on it. @LaTeX{} is ubiquitous in academic literature. The current version of @LaTeX{} is under active development; more information is available online at @uref{https://www.latex-project.org/}. The @LaTeX{} output can be further processed into DVI, PostScript, or PDF@. In theory, the @LaTeX{} output should allow for much more customizability of the output than would be possible with the plain @TeX{} implementation of Texinfo. @cindex DocBook output, overview @cindex XML DocBook output, overview @item DocBook (Generated via @command{texi2any --docbook}.) This is an XML-based format, primarily for technical documentation. It therefore bears some resemblance, in broad outline, to Texinfo. See @uref{http://www.docbook.org}. Various converters from DocBook @emph{to} Texinfo have also been developed; see the Texinfo web pages. @cindex XML Texinfo output, overview @cindex Texinfo XML output, overview @cindex DTD, for Texinfo XML @pindex texinfo.dtd @pindex txixml2texi @item XML (Generated via @command{texi2any --xml}.) The @command{texi2any} XML output, unlike all the other output formats, is a transliteration of the Texinfo source, rather than finished output. Texinfo XML files cannot be viewed in web browsers or other programs. XML is a generic syntax specification usable for any sort of content. (A reference is at @uref{http://www.w3.org/XML}.) The purpose of the Texinfo XML output is to allow further processing by XML tools. The output syntax is defined in an XML DTD, which is contained in a file @file{texinfo.dtd} included in the Texinfo source distribution. The Texinfo source distribution includes a utility script @file{txixml2texi} to do a backward transformation to recreate the original Texinfo content (except for Texinfo macros and conditionals). @end table @node Info Files @nodedescription What is an Info file? @section Info Files @cindex Info files As mentioned above, Info format is mostly a plain text transliteration of the Texinfo source, with the addition of a few control characters to separate nodes and provide navigational information, so that Info-reading programs can operate on it. Info files are nearly always created by processing a Texinfo source document. @command{texi2any}, also known as @command{makeinfo}, is the principal command that converts a Texinfo file into an Info file; @pxref{Generic Translator @command{texi2any}}. Generally, you enter an Info file through a node that by convention is named `Top'. This node normally contains just a brief summary of the file's purpose, and a large menu through which the rest of the file is reached. From this node, you can either traverse the file systematically by going from node to node, or you can go to a specific node listed in the main menu, or you can search the index menus and then go directly to the node that has the information you want. Alternatively, with the standalone Info program, you can specify specific menu items on the command line (@pxref{Top,,, info, Info}). If you want to read through an Info file in sequence, as if it were a printed manual, you can hit @key{SPC} repeatedly, or you get the whole file with the advanced Info command @kbd{g *}. (@xref{Advanced,, Advanced Info commands, info, Info}.) The @file{dir} file in the @file{info} directory serves as the departure point for the whole Info system. From it, you can reach the `Top' nodes of each of the documents in a complete Info system. @cindex URI syntax for Info If you wish to refer to an Info file via a URI, you can use the (unofficial) syntax exemplified by the following. This works with Emacs/W3, for example: @example info:emacs#Dissociated%20Press info:///usr/info/emacs#Dissociated%20Press info://localhost/usr/info/emacs#Dissociated%20Press @end example The @command{info} program itself does not follow URIs of any kind. @node Printed Books @nodedescription Characteristics of a printed book or manual. @section Printed Books @cindex Printed book and manual characteristics @cindex Manual characteristics, printed @cindex Book characteristics, printed @cindex Texinfo printed book characteristics @cindex Characteristics, printed books or manuals @cindex Knuth, Donald A Texinfo file can be formatted and typeset as a printed book or manual. To do this, you need @TeX{}, a sophisticated typesetting program written by Donald Knuth of Stanford University. It is not part of the Texinfo distribution. Texinfo provides a file @file{texinfo.tex} that contains the definitions that @TeX{} uses when it typesets a Texinfo file. You can get the latest version of @file{texinfo.tex} from the Texinfo home page, @uref{http://www.gnu.org/software/texinfo/}. A Texinfo-based book is similar to any other typeset, printed work: it can have a title page, copyright page, table of contents, and preface, as well as chapters, numbered or unnumbered sections and subsections, page headers, cross-references, footnotes, and indices. @TeX{} is very powerful and has a great many features. However, because a Texinfo file must be able to present information both on a character-only terminal in Info form and in a typeset book, the formatting commands that Texinfo supports are necessarily limited. @xref{Hardcopy with @TeX{}}, for more information on processing a manual with @TeX{}. @node Adding Output Formats @nodedescription Man pages and implementing new formats. @section Adding Output Formats @cindex Additional output formats The output formats in the previous sections handle a wide variety of usage, but of course there is always room for more. @cindex Output formats, supporting more @cindex SGML-tools output format If you are a programmer and would like to contribute to the GNU project by implementing additional output formats for Texinfo, that would be excellent. The way to do this that would be most useful is to write a new back-end for @command{texi2any}, our reference implementation of a Texinfo parser; it creates a tree representation of the Texinfo input that you can use for the conversion. The documentation in the source file @file{tp/Texinfo/Convert/Converter.pm} is a good place to start (@pxref{Texinfo::Convert::Converter,,,texi2any_internals,Texinfo modules documentation}). @xref{Generic Translator @command{texi2any}}. Another viable approach is use the Texinfo XML output from @command{texi2any} as your input. This XML is an essentially complete representation of the input, but without the Texinfo syntax and option peculiarities, as described above. @cindex Texinfo parsers, discouraging more If you still cannot resist the temptation of writing a new program that reads Texinfo source directly, let us give some more caveats: please do not underestimate the amount of work required. Texinfo is by no means a simple language to parse correctly, and remains under development, so you would be committing to an ongoing task. You are advised to check that the tests of the language that come with @command{texi2any} give correct results with your new program. @cindex Man page output, not supported From time to time, proposals are made to generate traditional Unix man pages from Texinfo source. However, because man pages have a strict conventional format, creating a good man page requires a completely different source from that needed for the typical Texinfo applications of writing a good user tutorial and/or a good reference manual. This makes generating man pages incompatible with the Texinfo design goal of not having to document the same information in different ways for different output formats. You might as well write the man page directly. @pindex help2man @cindex O'Dea, Brendan As an alternative way to support man pages, you may find the program @command{help2man} to be useful. It generates a traditional man page from the @samp{--help} output of a program. In fact, the man pages for the programs in the Texinfo distribution are generated with this. It is GNU software written by Brendan O'Dea, available from @uref{http://www.gnu.org/software/help2man}. @node History @nodedescription Acknowledgements, contributors and genesis. @section History @cindex Stallman, Richard M. @cindex Chassell, Robert J. @cindex Fox, Brian @cindex Berry, Karl @cindex Smith, Gavin Richard M. Stallman invented the Texinfo format, wrote the initial processors, and created Edition 1.0 of this manual. Robert@tie{}J. Chassell greatly revised and extended the manual, starting with Edition 1.1. Brian Fox was responsible for the standalone Texinfo distribution until version 3.8. Karl Berry continued maintenance from Texinfo 3.8 (manual edition 2.22), and Gavin Smith has continued maintenance since Texinfo 6.0. @cindex History of Texinfo @cindex Texinfo history @subheading Beginnings @cindex NLS Richard Stallman included an on-line, hypertext help system called Info in the original implementation of Emacs (in 1975/6). Stallman had been inspired after seeing a presentation a couple of years earlier on the ``NLS'' hypertext system of Douglas Engelbart. @ignore From rms@santafe.edu Sat Jan 23 03:41:05 1999 Status: RO X-VM-v5-Data: ([nil nil nil nil nil nil nil nil nil] [nil nil nil nil nil nil nil nil nil nil nil nil "^Date:" nil nil nil ni +l nil nil nil nil] nil) Reply-to: rms@gnu.org Content-Length: 331 Date: Sat, 23 Jan 1999 01:40:59 -0700 (MST) From: Richard Stallman To: bob@rattlesnake.com CC: karl@cs.umb.edu, kama@hippo.fido.de, bug-texinfo@gnu.org Subject: Re: Q: Some history questions People at MIT also developed a nifty on-line help format called Info. That was me. I developed Info as a sort of "poor man's hypertext" after I saw a presentation on NLS (Englebart's hypertext system). I THINK this was in 1974, actually before Emacs, and that after developing Emacs in 1975 I adapted Info to work with it. @end ignore @cindex Scribe @cindex Reid, Brian In another development, in the 1970's at CMU, Brian Reid developed a program and format named Scribe to mark up documents for printing. It used the @code{@@} character to introduce commands, as Texinfo does. Much more consequentially, it strove to describe document contents rather than formatting, an idea wholeheartedly adopted by Texinfo. @cindex Bolio @cindex Bo@TeX{} Meanwhile, people at MIT developed another format called Bolio. Richard Stallman (RMS) worked on converting Bolio to use @TeX{} as its typesetting language, resulting in Bo@TeX{}. The earliest Bo@TeX{} version seems to have been 0.02 on October 31, 1984. Bo@TeX{} could only be used as a markup language for documents to be printed, not for online documents. RMS combined Bo@TeX{} and Info to create Texinfo, a mark-up language for text that is intended to be read both online and as printed hard copy. The original translator to create Info was written (primarily by RMS and Bob Chassell) in Emacs Lisp, namely the @code{texinfo-format-buffer} and other functions. In the early 1990s, Brian Fox reimplemented the conversion program in C, now called @command{makeinfo}, as well as the standalone @command{info} program. @subheading Reimplementing in Perl @cindex Cons, Lionel @cindex Dumas, Patrice In 2012, the C @command{makeinfo} was itself replaced by a Perl implementation generically called @command{texi2any}. This version supports the same level of output customization as @command{texi2html}, an independent program originally written by Lionel Cons, later with substantial work by many others. The many additional features needed to make @command{texi2html} a replacement for @command{makeinfo} were implemented by Patrice Dumas. The first, never-released version of @command{texi2any} was based on the @command{texi2html} code. @cindex Tree representation of documents @cindex Syntax tree representation of documents @cindex Abstract syntax tree representation of documents That implementation, however, was abandoned in favor of the current program (also written by Patrice Dumas), which parses the Texinfo input into a tree for processing. It inherited the design of customization and other features from @command{texi2html} (for more on @command{texi2html} compatibility, @pxref{@command{texi2html}}). However, @command{texi2any} is a full reimplementation: it constructs a tree-based representation of the input document for all back-ends to work from. The new Perl program is much slower than the old C program. The speed gap has partially closed since first release, but it may not ever be entirely comparable. So why did we switch? In short, we intend and hope that the present program will be much easier than the previous C implementation of @command{makeinfo} to extend to different output styles, back-end output formats, and all other customizations. In more detail: @itemize @bullet @item HTML customization. Many GNU and other free software packages had been happily using the HTML customization features in @command{texi2html} for years. Thus, in effect two independent implementations of the Texinfo language had developed, and keeping them in sync was not simple. Adding the HTML customization possible in @command{texi2html} to a C program would have been an enormous effort. @item Unicode, and multilingual support generally, especially of east Asian languages. At that time, doing it in C would have been tantamount to rewriting the entire program. Since then, the parser and bits of converter back-ends have been rewritten in C, but the converter back-ends are still mostly in Perl which has good multilingual support built in. @item Additional back-ends. The @command{makeinfo} code had become convoluted to the point where adding a new back-end was quite complex, requiring complex interactions with existing back-ends. In contrast, the new implementation provides a clean tree-based representation for all back-ends to work from. People have requested numerous different back-ends (@LaTeX{}, the latest (X)HTML, @dots{}); this change made them much more feasible to implement. Which leads to the last item: @item Making contributions easier. In general, due to the cleaner structure, the separate parser/back-ends implementation should be considerably easier than the former C @command{makeinfo} implementation for anyone to read and contribute to, with the resulting obvious benefits. After ten years, contributed back-ends were yet to happen, but it is still believed that this structure could in theory lend better to contributions. @end itemize @cindex @command{texi2any}, as reference implementation @cindex Reference implementation @cindex Implementation, @command{texi2any} as reference @cindex Texinfo language tests @cindex Tests, of Texinfo language @anchor{Reference Implementation}@c @command{texi2any} is intended to be a reference implementation that defines parts of the language not fully specified by the manual. Without such a reference, alternative implementations would be very likely to have subtle, or not-so-subtle, differences in behavior, and thus Texinfo documents would become dependent on the processor. It is also important to have consistent command-line options for all processors. Extensive tests of the language and processor were developed at the same time as @command{texi2any}; we encourage anyone thinking of writing a program to parse Texinfo input to make use of these tests. @cindex Future of Texinfo implementations With the release of @command{texi2any} as the reference implementation, development of both the C implementation of @command{makeinfo} and @command{texi2html} has been halted. Going forward, we ask authors of Texinfo documents to use only @command{texi2any}. @node Writing a Texinfo File @anchor{Beginning and Ending a File}@c old name @nodedescription Format of a Texinfo source file. @chapter Writing a Texinfo File This chapter describes Texinfo syntax and what is required in a Texinfo file, and gives a short sample file. @node Conventions @nodedescription General rules for writing a Texinfo file. @section General Syntactic Conventions @cindex General syntactic conventions @cindex Syntactic conventions @cindex Conventions, syntactic @cindex Characters, basic input @anchor{Formatting Commands} @c old name This section describes the general conventions used in all Texinfo documents. @itemize @bullet @item @cindex Source files, characters used All printable ASCII characters except @samp{@@}, @samp{@{} and @samp{@}} can appear in a Texinfo file and stand for themselves. @samp{@@} is the escape character which introduces commands, while @samp{@{} and @samp{@}} are used to surround arguments to certain commands. To put one of these special characters into the document, put an @samp{@@} character in front of it, like this: @samp{@@@@}, @samp{@@@{}, and @samp{@@@}}. @item @cindex @sortas{at} @@-commands @cindex Formatting commands In a Texinfo file, the commands you write to describe the contents of the manual are preceded by an @samp{@@} character; they are called @dfn{@@-commands}. (The @samp{@@} in Texinfo has the same meaning that @samp{\} has in plain @TeX{}.) @cindex Braces, when to use Depending on what they do or what arguments they take, you need to write @@-commands on lines of their own, or as part of sentences. As a general rule, a command requires braces if it mingles among other text; but it does not need braces if it is on a line of its own. For more details of Texinfo command syntax, see @ref{Command Syntax}. @item Whitespace following an @@-command name is optional and (usually) ignored if present. The exceptions are contexts when whitespace is significant, e.g., an @code{@@example} environment. @item Texinfo supports the usual quotation marks used in English and in other languages; see @ref{Inserting Quotation Marks}. @item @cindex Multiple dashes in source @cindex Dashes in source @cindex Hyphens in source, two or three in a row @cindex Em dash, producing @cindex En dash, producing Use three hyphens in a row, @samp{---}, to produce a long dash---like this (called an @dfn{em dash}), used for punctuation in sentences. Use two hyphens, @samp{--}, to produce a medium dash (called an @dfn{en dash}), used primarily for numeric ranges, as in ``June 25--26''. Use a single hyphen, @samp{-}, to produce a standard hyphen used in compound words. For display on the screen, Info reduces three hyphens to two and two hyphens to one (not transitively!). Of course, any number of hyphens in the source remain as they are in literal contexts, such as @code{@@code} and @code{@@example}. @item @emph{Whitespace}. Texinfo files are plain text files composed of lines terminated by the usual newline character (line feed). Texinfo processors read input one line at a time. Paragraphs are terminated by an empty line or a line containing only spaces. A sequence of several spaces in text is usually treated the same as a single space (except in verbatim modes). @cindex Form feed character @cindex @kbd{CTRL-l} Form feed (@kbd{CTRL-l}) characters in normal text end any open paragraph. Other ASCII whitespace (tab, carriage return) may be treated the same as space characters, although the results may differ depending on output format. Hence, there is not much point in using these in documents. Non-ASCII spaces, such as Unicode ``em space'', are not recognized as whitespace at all and will be treated as regular, non-whitespace characters. However, in verbatim modes, for example in code samples, tab characters may produce the correct formatting in the output. @ignore @c Excessive detail? To avoid this problem, Texinfo mode in GNU Emacs inserts multiple spaces when you press the @key{TAB} key. Also, you can run @code{untabify} in Emacs to convert tabs in a region to multiple spaces, or use the @code{unexpand} command from the shell. @end ignore @ignore @c too detailed for the manual, but kept for implementation tips @item Form feed characters outside of a paragraph are handled as follows: @table @asis @item PDF/DVI Ignored between paragraphs. @item LaTeX Ignored in contexts where spaces are ignored except after specific commands closing braces (@code{@@caption} for example). Left as is in the output otherwise. @c Written as @code{\par@{@}}, a @LaTeX{} macro that starts a paragraph. @item Info Output as-is between paragraphs (their most common use); ignored in contexts where spaces are ignored except after specific commands closing braces (@code{@@caption} for example). In other contexts, they may be treated as regular spaces (and thus consolidated with surrounding whitespace). @item HTML Written as a numeric entity except contexts where spaces are ignored; for example, in @samp{@@footnote@{ ^L foo@}}, the form feed is ignored. @item XML Keep them everywhere; in attributes, escaped as @samp{\f}; also, @samp{\} is escaped as @samp{\\} and newline as @samp{\n}. @item DocBook Completely removed, as they are not allowed. @end table As you can see, because of these differing requirements of the output formats, it's not possible to use form feeds completely portably. @end ignore @end itemize @node Comments @nodedescription Writing comments and ignored text in general. @section Comments @cindex Comments @findex comment @findex c You can write comments in a Texinfo file by using the @code{@@comment} command, which may be abbreviated to @code{@@c}. Such comments are for a person looking at the Texinfo source file. All the text on a line that follows either @code{@@comment} or @code{@@c} is a comment; the rest of the line does not appear in the visible output. (To be precise, the character after the @code{@@c} or @code{@@comment} must be something other than a dash or alphanumeric, or it will be taken as part of the command.) Often, you can write the @code{@@comment} or @code{@@c} in the middle of a line, and only the text that follows after the @code{@@comment} or @code{@@c} command does not appear; but some commands, such as @code{@@settitle}, work on a whole line. You cannot use @code{@@comment} or @code{@@c} within a line beginning with such a command. @findex DEL @r{(comment character)} @cindex Catcode for comments in @TeX{} In cases of nested command invocations, complicated macro definitions, etc., @code{@@c} and @code{@@comment} may provoke an error when processing with @TeX{}. Therefore, you can also use the @kbd{DEL} character (ASCII 127 decimal, 0x7f hex, 0177 octal) as a true @TeX{} comment character (catcode 14, in @TeX{} internals). Everything on the line after the @kbd{DEL} will be ignored and the next line will be merged. @cindex Ignored text @cindex Unprocessed text @findex ignore You can also have long stretches of text ignored by the Texinfo processors with the @code{@@ignore} and @code{@@end ignore} commands. Write each of these commands on a line of its own, starting each command at the beginning of the line. Text between these two commands does not appear in the processed output. You can use @code{@@ignore} and @code{@@end ignore} for writing comments. (For some caveats regarding nesting of such commands, @pxref{Conditional Nesting}.) @node Minimum @nodedescription What a Texinfo file must have. @section What a Texinfo File Must Have @cindex Minimal Texinfo file (requirements) @cindex Required in Texinfo file @cindex Texinfo file minimum By convention, the name of a Texinfo file ends with one of the extensions @file{.texi}, @file{.texinfo}, @file{.txi}, or @file{.tex}. Using @file{.tex} is discouraged as this extension is already used by @TeX{} and @LaTeX{} input files. The most common and recommended extension is @file{.texi}. The name of a Texinfo file should only contain ASCII characters. The output name is based on the input file name, in the default case. First, any of the extensions @file{.texi}, @file{.tex}, @file{.txi}, or @file{.texinfo} is removed from the input file name; then, the output format specific extension is added---@file{.html} when generating HTML, @file{.info} when generating Info, etc. The output name should only contain ASCII characters@footnote{@command{texi2any} can handle non ASCII characters in input file names, but non ASCII characters in output name will create problems for some output formats, especially for cross-references.}. @cindex Requirements for formatting @cindex Minimal requirements for formatting @cindex Formatting requirements In order to be made into a printed manual, a Texinfo file must begin with a line like this: @example @group \input texinfo @end group @end example @noindent The contents of the file follow this beginning, and then you must end the Texinfo source with a line like this: @example @@bye @end example @findex \input @r{(raw @TeX{} startup)} The @code{@@bye} line at the end of the file on a line of its own tells @TeX{} that the file is ended and to stop formatting. If you leave this out, you'll be dumped at @TeX{}'s prompt at the end of the run. Furthermore, you will usually provide a Texinfo file with a title, a title page, indices, and the like, all of which are explained in this manual. But the minimum, which can be useful for short documents, is just the one line at the beginning and the one line at the end. Without additional information, the input and output encodings are assumed to be UTF-8, an universal codeset compatible with 7-bit ASCII. @node Short Sample Texinfo File @nodedescription A short sample Texinfo file. @anchor{Short Sample}@c @anchor{Sample Beginning}@c @section Short Sample @cindex Sample Texinfo file, no comments Here is a short sample Texinfo file. @example \input texinfo @@settitle Sample Manual 1.0 @@copying This is a short example of a complete Texinfo file. Copyright @@copyright@{@} 2016 Free Software Foundation, Inc. @@end copying @@titlepage @@title Sample Title @@page @@vskip 0pt plus 1filll @@insertcopying @@end titlepage @@contents @@node Top @@top GNU Sample This manual is for GNU Sample (version @@value@{VERSION@}, @@value@{UPDATED@}). @@menu * First Chapter:: The first chapter is the only chapter in this sample. * Index:: Complete index. @@end menu @@node First Chapter @@chapter First Chapter @@cindex chapter, first This is the first chapter. @@cindex index entry, another @group Here is a numbered list. @@enumerate @@item This is the first item. @@item This is the second item. @@end enumerate @end group @@node First Section @@section First Section First section of first chapter. @@node Second Section @@section Second Section Second section of first chapter. @@node Index @@unnumbered Index @@printindex cp @@bye @end example @node Texinfo File Header @nodedescription The first lines. @section Texinfo File Header @cindex Header for Texinfo files @cindex Texinfo file header Texinfo files start with the line: @example \input texinfo @end example The @samp{\input texinfo} line tells @TeX{} to use the @file{texinfo.tex} file, which tells @TeX{} how to translate the Texinfo @@-commands into @TeX{} typesetting commands. (Note the use of the backslash, @samp{\}; this is correct for @TeX{}.) It makes sense to include any command that affects document formatting as a whole in the header. The @code{@@settitle} line is usually present at the beginning of the header: @example @@settitle Sample Manual 1.0 @end example The @code{@@settitle} line specifies a title for the page headers (or footers) of the printed manual, and the default title and document description for the @samp{} in HTML@. @code{@@synindex} (@pxref{@code{@@synindex}}), for instance, is another command often included in the header. The start of the Texinfo file up to the first content that is output as part of the main body of the document is the @dfn{preamble}. It includes the header, @ref{Document Permissions} and @ref{Titlepage & Copyright Page} specification. It is important for the @LaTeX{} output format as the end of preamble is where the @code{\begin@{document@}} line is output. In other output formats it may be used to determine how some special output is formatted, for example @ref{@code{@@copying}} output as a comment at the beginning of output files, or the language used in file headers. @node First Line @subsection The First Line of a Texinfo File @nodedescription The first line of a Texinfo file. @cindex First line of a Texinfo file @cindex Beginning line of a Texinfo file @cindex Header of a Texinfo file Every Texinfo file that is to be the top-level input to @TeX{} must begin with a line that looks like this: @example \input texinfo @end example When the file is processed by @TeX{}, the @samp{\input texinfo} command tells @TeX{} to load the macros needed for processing a Texinfo file. These are in a file called @file{texinfo.tex}, which should have been installed on your system along with either the @TeX{} or Texinfo software. @TeX{} uses the backslash, @samp{\}, to mark the beginning of a command, exactly as Texinfo uses @samp{@@}. The @file{texinfo.tex} file causes the switch from @samp{\} to @samp{@@}; before the switch occurs, @TeX{} requires @samp{\}, which is why it appears at the beginning of the file. You may optionally follow this line with a comment to tell GNU Emacs to use Texinfo mode when the file is edited: @example \input texinfo @@c -*-texinfo-*- @end example @noindent This may be useful when Emacs doesn't detect the file type from the file extension automatically. @node @code{@@setfilename} @nodedescription Give the name of the output file. @subsection @code{@@setfilename}: Set the Output File Name @anchor{setfilename}@c old name @c used in references when the reference is not about @setfilename @c in particular, but about the output file name, be it from @setfilename @c or from the input file name. @anchor{Setting the Output File Name} @findex setfilename @cindex output file name The @code{@@setfilename} line specifies the name of the output file to be generated by @command{texi2any}. This command is ignored for @TeX{} formatting. When present, it should be the first Texinfo command (that is, after @samp{\input texinfo}). Write the @code{@@setfilename} command at the beginning of a line and follow it on the same line by the Info file name. @example @@setfilename @var{info-file-name} @end example The name must be different from the name of the Texinfo file. There are two conventions for choosing the name: you can either remove the extension (such as @samp{.texi}) entirely from the input file name, or (recommended) replace it with the @samp{.info} extension. It is not advised to base the @code{@@setfilename} name on a entirely different name than the input file name. @cindex Ignored before @code{@@setfilename} @cindex @samp{\input} source line ignored When a @code{@@setfilename} line is present, the Texinfo processors ignore everything written before the @code{@@setfilename} line. This is why the very first line of the file (the @code{\input} line) does not show up in the output. If there is no @code{@@setfilename} line, @command{texi2any} uses the input file name to determine the output name (@pxref{Minimum}). The @code{\input} line is still ignored in this processing, as well as leading blank lines. When producing another output format, @command{texi2any} will replace any final extension with the output format-specific extension (@samp{html} when generating HTML, for example), or add a dot followed by the extension (@samp{.html} for HTML) if the given name has no extension. @@-commands are not allowed in @code{@@setfilename}, except for @code{@@@@}, @code{@@@{}, @code{@@@}} and associated @@-commands such as @code{@@atchar@{@}}. @code{@@setfilename} used to be required by the Texinfo processors and some other programs. This should not be the case any more; @code{@@setfilename} can be omitted. If the Texinfo input is processed from standard input, without an input file name to deduce the base file name from, @code{@@setfilename} could still be relevant. This is not the only way, however: @option{--output} option specifies the output file name on the @command{texi2any} command-line (@pxref{Invoking @command{texi2any}}). @cindex Length of file names @cindex File name collision @cindex Info file name, choosing Although an explicit @samp{.info} extension is preferable, some operating systems cannot handle long file names. You can run into a problem even when the file name you specify is itself short enough. This occurs because the Info formatters split a long Info file into short indirect subfiles, and name them by appending @samp{-1}, @samp{-2}, @dots{}, @samp{-10}, @samp{-11}, and so on, to the original file name. (@xref{Tag and Split Files}.) The subfile name @file{texinfo.info-10}, for example, is too long for old systems with a 14-character limit on filenames; so the Info file name for this document could be @file{texinfo} rather than @file{texinfo.info} on such a system. @code{@@setfilename} is a way to specify an alternative name. @node @code{@@settitle} @nodedescription Create a title for the printed work. @subsection @code{@@settitle}: Set the Document Title @anchor{settitle}@c old name @findex settitle @cindex Document title, specifying A Texinfo file should contain a line that looks like this: @example @@settitle @var{title} @end example Write the @code{@@settitle} command at the beginning of a line and follow it on the same line by the title. Do not write anything else on the line. The @code{@@settitle} command should precede everything that generates actual output. The best place for it is right after the @code{@@setfilename} command, if present (described in the previous section). This command gives the title to use in a header or footer for double-sided printed output, in case such headings are output. For more on headings for printed output, see @ref{Heading Generation}. @cindex @code{} HTML tag In HTML, @var{title} serves as the document @samp{<title>} and it becomes the default document description in the @samp{<head>} part. When the title page is used in the output, as is generally the case for printed output, the title in the @code{@@settitle} command does not affect the title as it appears on the title page. Thus, the two do not need not to match exactly. A practice we recommend is to include the version or edition number of the manual in the @code{@@settitle} title; on the title page, the version number generally appears as a @code{@@subtitle} so it would be omitted from the @code{@@title}. @xref{@code{@@titlepage}}. @node Preamble @nodedescription Start of the Texinfo file up to first content. @subsection Preamble @cindex Preamble @cindex Texinfo Preamble The @dfn{preamble} starts at the beginning of the Texinfo file and continues until the first directly output material. It typically includes the file header (@pxref{Texinfo File Header}), the @code{@@copying} block specifying the document permissions (@pxref{@code{@@copying}}) and the @code{@@titlepage} specification (@pxref{Titlepage & Copyright Page}). The preamble may contain commands that affect document formatting as a whole but which do not produce output, or do not produce output straight away, such as @code{@@settitle} (@pxref{@code{@@settitle}}), @code{@@documentlanguage}, (@pxref{@code{@@documentlanguage}}), commands setting the headings, controlling indentation or hyphenation, or the table of contents (@pxref{Contents}). @ignore The preamble can also contain raw formatter commands (@pxref{Raw Formatter Commands}), but it is not checked that the content of these commands is actually preamble material and not regular output. @end ignore Any text that starts a paragraph, @@-commands that are formatted as quotations, tables, lists and so on, and @code{@@node} (@pxref{Nodes}) and chapter structuring commands (@pxref{Chapter Structuring}) end the preamble. The concept of the preamble is significant for @LaTeX{} output, as the @code{\begin@{document@}} line is output at the end of the preamble. In plaintext, the preamble is simply output as usual at the beginning of the document; for example, a @code{@@contents} in the preamble is output as the table of contents (@pxref{Contents}). There is not much special treatment of the preamble for HTML and Info output either. However, some settings current at the very end of the preamble may be used for the document as a whole, regardless of what follows. This may apply to commands specifying the indentation, or the language (@pxref{@code{@@documentlanguage}}). For example, for the following document, the HTML and Info copying comments are formatted with @code{@@documentlanguage} set to @samp{pt}, as it is the last @code{@@documentlanguage} before the end of the preamble. @example @group \input texinfo @@documentlanguage fr @@copying The copying information @@error@{@} some text @@end copying @@documentlanguage pt Text ending the preamble @@documentlanguage de @@node Top @end group @end example @node Start and End of Header @nodedescription Formatting a region in Emacs requires this. @subsection Start and End of Header for Emacs @anchor{Start of Header}@c old name @cindex Start of header line In Emacs, start- and end-of-header lines can be used to enclose commands that globally affect the document in the Texinfo preambule. This allows you to format only part of a Texinfo file for Info or printing. @xref{@code{texinfo-format} commands}. A start-of-header line is a Texinfo comment that looks like this: @example @@c %**start of header @end example Write the start-of-header line on the second line of a Texinfo file. Follow the start-of-header commands that globally affect the document formatting, such as @code{@@settitle}, @code{@@synindex} or @code{@@footnotestyle}; and then by an @w{end-of-header} line. @anchor{End of Header}@c old name @cindex End of header line A end-of-header line is a Texinfo comment that looks like this: @example @@c %**end of header @end example The odd string of characters, @samp{%**}, is to ensure that no other comment is accidentally taken for a start-of-header line. You can change it if you wish by setting the @code{tex-start-of-header} and/or @code{tex-end-of-header} Emacs variables. @xref{Texinfo Mode Printing}. The start- and end-of-header lines are not part of the Texinfo format specification, which is why they are implemented with comments. @node Directory Category @nodedescription A category for a manual. @section Directory Category @findex dircategory @cindex Dir categories, choosing @cindex Categories, choosing Use the @code{@@dircategory} command to specify a category for the manual. Here are a few examples of category names: @c from util/dir-example @c we used to recommend looking at Free Software Directory categories @c but these have changed @display Basics Text creation and manipulation Archiving Compression Database Editors Emacs Email Graphics Localization Network applications Printing Science Software development Software libraries Version control @end display @code{@@dircategory} commands are usually followed by a @code{@@direntry} blocks, which are used by @command{install-info}. @xref{Installing Dir Entries}, for details. The first @code{@@dircategory} command in a manual is the category for the entire manual. Subsequent uses of @code{@@dircategory} set the category for following @code{@@direntry} blocks only. @node Document Permissions @nodedescription Ensuring your manual is free. @anchor{Software Copying Permissions}@c old node name @section Document Permissions @cindex Document permissions @cindex Copying permissions This segment describes the document and contains the copyright notice and copying permissions. This is done with the @code{@@copying} command. A real manual includes more text here, according to the license under which it is distributed. @example @group @@copying This is a short example of a complete Texinfo file, version 1.0. Copyright @@copyright@{@} 2016 Free Software Foundation, Inc. @@end copying @end group @end example The copyright notice and copying permissions for a document need to appear in several places in the various Texinfo output formats. Therefore, Texinfo provides a command (@code{@@copying}) to declare this text once, and another command (@code{@@insertcopying}) to insert the text at appropriate points. If the document is a software manual, the software is typically under a different license---for GNU and many other free software packages, software is usually released under the GNU GPL, and manuals are released under the GNU FDL@. It is helpful to state the license of the software of the manual, but giving the complete text of the software license is not necessarily required. @node @code{@@copying} @nodedescription Declare the document's copying permissions. @subsection @code{@@copying}: Declare Copying Permissions @anchor{copying}@c old name @findex copying The @code{@@copying} command should be given very early in the document; the recommended location is right after the header material (@pxref{Texinfo File Header}). It conventionally consists of a sentence or two about what the program is, identification of the documentation itself, the legal copyright line, and the copying permissions. Here is a skeletal example: @example @@copying This manual is for @var{program} (version @var{version}, updated @var{date}), which @dots{} Copyright @@copyright@{@} @var{years} @var{copyright-owner}. @@quotation Permission is granted to @dots{} @@end quotation @@end copying @end example The @code{@@quotation} has no legal significance; it's there to improve readability in some contexts. The text of @code{@@copying} appears as a comment at the beginning of Info and HTML output files. This information is also output at the beginning of the DocBook output files using appropriate markup. It is @emph{not} output implicitly in plain text or printed output; it's up to you to use @code{@@insertcopying} to emit the copying information. See the next section for details. The @code{@@copyright@{@}} command generates a @samp{c} inside a circle when the output format supports this glyph (print and HTML always do, for instance). When the glyph is not supported in the output, it generates the three-character sequence @samp{(C)}. The copyright notice itself has the following legally-prescribed form: @example Copyright @copyright{} @var{years} @var{copyright-owner}. @end example @cindex Copyright word, always in English The word `Copyright' must always be written in English, even if the document is otherwise written in another language. This is due to international law. @cindex Years, in copyright line The list of years should include all years in which a version was completed (even if it was released in a subsequent year). It is simplest for each year to be written out individually and in full, separated by commas. @cindex Copyright holder for FSF works @cindex Holder of copyright for FSF works @cindex Owner of copyright for FSF works The copyright owner (or owners) is whoever holds legal copyright on the work. In the case of works assigned to the FSF, the owner is `Free Software Foundation, Inc.'. The copyright `line' may actually be split across multiple lines, both in the source document and in the output. This often happens for documents with a long history, having many different years of publication. If you do use several lines, do not indent any of them (or anything else in the @code{@@copying} block) in the source file. @xref{Copyright Notices,,, maintain, GNU Maintainer Information}, for additional information. @xref{GNU Sample Texts}, for the full text to be used in GNU manuals. @xref{GNU Free Documentation License}, for the license itself under which GNU and other free manuals are distributed. @node @code{@@insertcopying} @nodedescription Where to insert the permissions. @subsection @code{@@insertcopying}: Include Permissions Text @anchor{insertcopying}@c old name @findex insertcopying @cindex Copying text, including @cindex Permissions text, including @cindex Including permissions text The @code{@@insertcopying} command is simply written on a line by itself, like this: @example @@insertcopying @end example This inserts the text previously defined by @code{@@copying}. To meet legal requirements, it must be used on the copyright page in the printed manual (@pxref{Copyright}). The @code{@@copying} command itself causes the permissions text to appear in an Info file @emph{before} the first node. The text is also copied into the beginning of each split Info output file, as is legally necessary. This location implies a human reading the manual using Info does @emph{not} see this text (except when using the advanced Info command @kbd{g *}). This does not matter for legal purposes, because the text is present. But to get a visible text in the output, @code{@@insertcopying} should be used. Similarly, the @code{@@copying} text is automatically included at the beginning of each HTML output file, as an HTML comment. Again, this text is not visible without @code{@@insertcopying} (unless the reader views the HTML source). The permissions text defined by @code{@@copying} also appears automatically at the beginning of the DocBook output files using appropriate markup. @code{@@insertcopying} can be used to output the permission text within normal text. @node Titlepage & Copyright Page @nodedescription Creating the title and copyright pages. @section Title and Copyright Pages In hard copy output, the manual's name and author are usually printed on a title page. Copyright information is usually printed on the back (verso) of the title page. This segment must be enclosed between @code{@@titlepage} and @code{@@end titlepage} commands: @example @group @@titlepage @@title Sample Title @end group @group @@c The following two commands start the copyright page. @@page @@vskip 0pt plus 1filll @@insertcopying @@end titlepage @end group @end example @noindent We use the @code{@@insertcopying} command to include the permission text from the previous section, instead of writing it out again. The title and copyright pages appear in printed manuals, but not in most other output formats. In HTML, the best way to get a title page similar to printed manuals is to set the @code{NO_TOP_NODE_OUTPUT} customization variable (@pxref{@code{NO_TOP_NODE_OUTPUT}}). @node @code{@@titlepage} @nodedescription Create a title for the printed document. @subsection @code{@@titlepage} @anchor{titlepage}@c old name @cindex Title page @findex titlepage Start the material for the title page and following copyright page with @code{@@titlepage} on a line by itself and end it with @code{@@end titlepage} on a line by itself. The @code{@@end titlepage} command starts a new page and turns on page numbering (@pxref{Heading Generation}). All the material that you want to appear on unnumbered pages should be put between the @code{@@titlepage} and @code{@@end titlepage} commands. @findex page@r{, within @code{@@titlepage}} By using the @code{@@page} command, you can force a page break within the region delineated by the @code{@@titlepage} and @code{@@end titlepage} commands and thereby create more than one unnumbered page. This is how the copyright page is produced. (The @code{@@titlepage} command might perhaps have been better named the @code{@@titleandadditionalpages} command, but that would have been rather long!) When you write a manual about a computer program, you should write the version of the program to which the manual applies on the title page. If the manual changes more frequently than the program or is independent of it, you should also include an edition number@footnote{We have found that it is helpful to refer to versions of independent manuals as `editions' and versions of programs as `versions'; otherwise, we find we are liable to confuse each other in conversation by referring to both the documentation and the software with the same words.} for the manual. This helps readers keep track of which manual is for which version of the program. (The `Top' node should also contain this information; see @ref{The Top Node}.) One method uses the @code{@@title}, @code{@@subtitle}, and @code{@@author} commands to create a title page. With this method, you do not specify any of the actual formatting of the title page. You specify the text you want, and Texinfo does the formatting. The usual formatting consist of black rules under the title and author lines and the subtitle text set flush to the right-hand side of the page. Texinfo also provides a second method for creating a title page. using typesetting commands that are not to be used in the main text. This method uses uses the @code{@@titlefont}, @code{@@sp}, and @code{@@center} commands to generate a title page in which the words on the page are centered. @findex shorttitlepage @cindex Bastard title page @cindex Title page @subentry bastard For sufficiently simple documents, and for the bastard title page in traditional book frontmatter, Texinfo also provides a command @code{@@shorttitlepage} which takes the rest of the line as the title. The argument is typeset on a page by itself and followed by a blank page. In HTML, @code{@@shorttitlepage} can play the same role as @code{@@settitle}, if @code{@@settitle} is not set. @xref{@code{@@settitle}}. @node @code{@@title @@subtitle @@author} @nodedescriptionblock The @code{@@title}, @code{@@subtitle}, and @code{@@author} commands. @end nodedescriptionblock @subsection @code{@@title}, @code{@@subtitle}, and @code{@@author} @anchor{title subtitle author}@c old name @findex title @findex subtitle @findex author You can use the @code{@@title}, @code{@@subtitle}, and @code{@@author} commands to create a title page in which the vertical and horizontal spacing is done for you automatically. Write the @code{@@title}, @code{@@subtitle}, or @code{@@author} commands at the beginning of a line followed by the title, subtitle, or author. The @code{@@author} command may be used for a quotation in an @code{@@quotation} block (@pxref{@code{@@quotation}}); except for that, it is an error to use any of these commands outside of @code{@@titlepage}. The @code{@@title} command normally produces a line in which the title is set flush to the left-hand side of the page in a larger than normal font. The title is underlined with a black rule. The title must be given on a single line in the source file; it will be broken into multiple lines of output is needed. For long titles, the @code{@@*} command may be used to specify the line breaks in long titles if the automatic breaks do not suit. Such explicit line breaks are generally reflected in all output formats; if you only want to specify them for the printed output, use a conditional (@pxref{Conditionals}). For example: @example @@title This Long Title@@inlinefmt@{tex,@@*@} Is Broken in @@TeX@{@} @end example The @code{@@subtitle} command normally sets subtitles in a normal-sized font flush to the right-hand side of the page. The @code{@@author} command normally sets the names of the author or authors in a middle-sized font flush to the left-hand side of the page on a line near the bottom of the title page. The names are followed by a black rule that is thinner than the rule that normally underlines the title. There are two ways to use the @code{@@author} command: you can write the name or names on the remaining part of the line that starts with an @code{@@author} command: @example @@author by Jane Smith and John Doe @end example @noindent or you can write the names one above each other by using multiple @code{@@author} commands: @example @group @@author Jane Smith @@author John Doe @end group @end example @need 950 A template for this method looks like this: @example @group @@titlepage @@title @var{name-of-manual-when-printed} @@subtitle @var{subtitle-if-any} @@subtitle @var{second-subtitle} @@author @var{author} @@page @dots{} @@end titlepage @end group @end example @node @code{@@titlefont @@center @@sp} @nodedescriptionblock The @code{@@titlefont}, @code{@@center}, and @code{@@sp} commands. @end nodedescriptionblock @subsection @code{@@titlefont}, @code{@@center}, and @code{@@sp} @anchor{titlefont center sp}@c old name @findex titlefont @findex center @findex sp @r{(titlepage line spacing)} You can also use the @code{@@titlefont}, @code{@@sp}, and @code{@@center} commands to create a title page for a printed document. Use the @code{@@titlefont} command to select a large font suitable for the title itself. You can use @code{@@titlefont} more than once if you have an especially long title. For HTML output, each @code{@@titlefont} command produces an @code{<h1>} heading, but the HTML document @code{<title>} is not affected. For that, you could put a @code{@@settitle} command before the @code{@@titlefont} command (@pxref{@code{@@settitle}}). @need 700 For example: @example @@titlefont@{Texinfo@} @end example Use the @code{@@center} command at the beginning of a line to center the remaining text on that line. Thus, @example @@center @@titlefont@{Texinfo@} @end example @noindent centers the title, which in this example is ``Texinfo'' printed in the title font. Use the @code{@@sp} command to insert vertical space. For example: @example @@sp 2 @end example @noindent This inserts two blank lines on the printed page. (@xref{@code{@@sp}}, for more information about the @code{@@sp} command.) A template for this method looks like this: @example @group @@titlepage @@sp 10 @@center @@titlefont@{@var{name-of-manual-when-printed}@} @@sp 2 @@center @var{subtitle-if-any} @@sp 2 @@center @var{author} @dots{} @@end titlepage @end group @end example The spacing of the example fits an 8.5 by 11 inch manual. @node Copyright @nodedescriptionblock How to write the copyright notice and include copying permissions. @end nodedescriptionblock @subsection Copyright Page @cindex Copyright page @cindex Printed permissions @cindex Permissions, printed By international treaty, the copyright notice for a book must be either on the title page or on the back of the title page. When the copyright notice is on the back of the title page, that page is customarily not numbered. Therefore, in Texinfo, the information on the copyright page should be within @code{@@titlepage} and @code{@@end titlepage} commands. @findex vskip @r{@TeX{} vertical skip} @cindex filll @r{@TeX{} dimension} Use the @code{@@page} command to cause a page break. To push the copyright notice and the other text on the copyright page towards the bottom of the page, use the following incantation after @code{@@page}: @example @@vskip 0pt plus 1filll @end example @noindent The @code{@@vskip} command inserts whitespace in the @TeX{} output; it is ignored in all other output formats. The @samp{0pt plus 1filll} means to put in zero points of mandatory whitespace, and as much optional whitespace as needed to push the following text to the bottom of the page. Note the use of three @samp{l}s in the word @samp{filll}; this is correct. To insert the copyright text itself, write @code{@@insertcopying} next (@pxref{Document Permissions}): @example @@insertcopying @end example Follow the copying text by the publisher, ISBN numbers, cover art credits, and other such information. Here is an example putting all this together: @example @@titlepage @dots{} @@page @@vskip 0pt plus 1filll @@insertcopying Published by @dots{} Cover art by @dots{} @@end titlepage @end example We have one more special case to consider: for plain text output, you must insert the copyright information explicitly if you want it to appear. For instance, you could have the following after the copyright page: @example @@ifplaintext @@insertcopying @@end ifplaintext @end example You could include other title-like information for the plain text output in the same place. @node Heading Generation @nodedescription Turn on page headings after the title and copyright pages. @subsection Heading Generation @anchor{end titlepage}@c old name @cindex Generating page headings Texinfo has two standard page heading formats, one for documents printed on one side of each sheet of paper (single-sided printing), and the other for documents printed on both sides of each sheet (double-sided printing). In full generality, you can control the headings in different ways: @itemize @bullet @item The conventional way is to write a @code{@@setchapternewpage} command before the title page commands. Most documents are formatted with the standard single-sided or double-sided headings, (sometimes) using @code{@@setchapternewpage odd} for double-sided printing and (almost always) no @code{@@setchapternewpage} command for single-sided printing (@pxref{@code{@@setchapternewpage}}). @item Alternatively, you can use the @code{@@headings} command to prevent page headings from being generated or to start them for either single or double-sided printing. To turn off headings, write @code{@@headings off}. @xref{@code{@@headings}}. @item Or, you may specify your own page heading and footing format. @xref{Headings}. @end itemize @node Contents @nodedescription How to create a table of contents. @section Generating a Table of Contents @cindex Table of contents @cindex Contents, table of @cindex Short table of contents @findex contents @findex summarycontents @findex shortcontents The @code{@@chapter}, @code{@@section}, and other structuring commands (@pxref{Chapter Structuring}) supply the information to make up a table of contents, but they do not cause an actual table to appear in the manual. To do this, you must use the @code{@@contents} and/or @code{@@summarycontents} command(s). @table @code @item @@contents Generates a table of contents in a printed manual, including all chapters, sections, subsections, etc., as well as appendices and unnumbered chapters. Headings generated by @code{@@majorheading}, @code{@@chapheading}, and the other @code{@@@dots{}heading} commands do not appear in the table of contents (@pxref{Structuring Command Types}). @item @@shortcontents @itemx @@summarycontents (@code{@@summarycontents} is a synonym for @code{@@shortcontents}.) Generates a short or summary table of contents that lists only the chapters, appendices, and unnumbered chapters. Sections, subsections and subsubsections are omitted. Only a long manual needs a short table of contents in addition to the full table of contents. @end table Both contents commands should be written on a line by themselves, and placed near the beginning of the file, after the @code{@@end titlepage} (@pxref{@code{@@titlepage}}), before any sectioning command. The contents commands automatically generate a chapter-like heading at the top of the first table of contents page, so don't include any sectioning command such as @code{@@unnumbered} before them. Since an Info file uses menus instead of tables of contents, the Info formatting commands ignore the contents commands. But the contents are included in plain text output and in other output formats, such as HTML. In HTML output, the links in the short table of contents point to corresponding entries in the full table of contents rather than the text of the document. The links in the full table of contents point to the main text of the document. @code{@@shortcontents} is not implemented for @LaTeX{} output. @node The Top Node @nodedescription Creating the `Top' node and master menu. @section The `Top' Node and Master Menu @cindex Top node @cindex Node, @samp{Top} @anchor{Top Node Example}@c The `Top' node is the node in which a reader enters an Info manual. As such, it should contain a very brief description of the manual (including the version number). The contents of the `Top' node do not appear in printed output nor in DocBook output. It is conventional to write a @code{@@top} sectioning command line containing the title of the document immediately after the @code{@@node Top} line (@pxref{@code{@@top} Command}). We repeat the short description from the beginning of the @samp{@@copying} text, but there's no need to repeat the copyright information, so we don't use @samp{@@insertcopying} here. The `Top' node contains a top-level @dfn{menu} listing the chapters, and possibly a @dfn{detailed menu} listing all the nodes in the entire document. @cindex Top node example @example @@node Top @@top Short Sample This is a short sample Texinfo file. @group @@menu * First Chapter:: The first chapter is the only chapter in this sample. * Index:: Complete index. @@end menu @end group @end example @menu * Master Menu Parts:: @end menu @node Master Menu Parts @subsection Parts of a Master Menu @cindex Master menu @cindex Menu, master @cindex Parts of a master menu A @dfn{master menu} is the main menu. It is customary to include a detailed menu listing all the nodes in the document in this menu. Like any other menu, a master menu is enclosed in @code{@@menu} and @code{@@end menu} and does not appear in the printed output nor in DocBook output. The master menu contains entries for the major nodes in the Texinfo file: the nodes for the chapters, chapter-like sections, and the appendices, followed by nodes for the indices. @findex detailmenu @cindex Detailed menu You may choose to follow these entries with a @dfn{detailed menu}. This lists other, lower-level nodes, often ordered by chapter. These items may be a convenience for an inquirer who can go directly to a particular node when searching for specific information, rather than going through an intermediate menu. If you use a detailed menu in your master menu, mark it with the @code{@@detailmenu @dots{} @@end detailmenu} environment. Each section in the menu can be introduced by a descriptive line. So long as the line does not begin with an asterisk, it will not be treated as a menu entry. (@xref{Writing a Menu}, for more information.) For example, the master menu for this manual looks like the following (but has many more entries): @example @group @@menu * Copying Conditions:: Your rights. * Overview:: Texinfo in brief. @dots{} @end group @group * Command and Variable Index:: * General Index:: @end group @group @@detailmenu --- The Detailed Node Listing --- Overview of Texinfo * Reporting Bugs:: @dots{} @dots{} @end group @group Beginning a Texinfo File * Sample Beginning:: @dots{} @dots{} @@end detailmenu @@end menu @end group @end example @node The Body of the Document @nodedescription The rest of the nodes. @section The Body of the Document @cindex Frontmatter, text in The body segment contains all the text of the document. A manual is divided into one or more @dfn{nodes} (@pxref{Nodes}). The example illustrates a chapter made of three nodes, one for introductory material in the chapter, and two sections. The introductory material contains an enumerated list. @example @group @@node First Chapter @@chapter First Chapter @@cindex chapter, first This is the first chapter. @@cindex index entry, another Here is a numbered list. @@enumerate @@item This is the first item. @@item This is the second item. @@end enumerate @@node First Section @@section First Section First section of first chapter. @@node Second Section @@section Second Section Second section of first chapter. @end group @end example In the Info output, the @samp{First Chapter} node will contain a menu listing the two sections in the chapter. Similarly, when this node is output in its own HTML file, it will contain a table of contents for the chapter. Here is what the contents of this chapter will look like: @sp 1 @need 700 @quotation @chapheading 1. First Chapter This is the first chapter. Here is a numbered list. @enumerate @item This is the first item. @item This is the second item. @end enumerate @heading 1.1 First Section First section of first chapter. @heading 1.2 Second Section Second section of first chapter. @end quotation @noindent (In the Info and HTML output, the chapter would also be split into nodes.) @node Ending a File @nodedescription What is at the end of a Texinfo file? @section Ending a Texinfo File @cindex Ending a Texinfo file @cindex Texinfo file ending @cindex File ending The end of a Texinfo file should include commands to create indices (@pxref{Printing Indices & Menus}), and the @code{@@bye} command to mark the last line to be processed. For example: @example @@node Index @@unnumbered Index @@printindex cp @@bye @end example @findex bye @anchor{File End} A @code{@@bye} command terminates Texinfo processing. It should be on a line by itself. Anything following @code{@@bye} is completely ignored. @node Nodes @nodedescription Writing nodes, the basic unit of Texinfo. @chapter Nodes @anchor{node}@anchor{@@node} @c old names @cindex Node, defined A @dfn{node} is a region of text that begins at a @code{@@node} command, and continues until the next @code{@@node} command. To specify a node, write a @code{@@node} command at the beginning of a line, and follow it with the name of the node. Info readers display one node at a time, and provide commands for the user to move to related nodes. The HTML output can be similarly navigated. Nodes are used as the targets of cross-references. Cross-references, such as the one at the end of this sentence, are made with @code{@@xref} and related commands; see @ref{Cross References}. Cross-references can be sprinkled throughout the text. Other @@-commands may also be the target of cross-references (@pxref{@code{@@anchor}}, @pxref{Floats}). Normally, you put a node command immediately before each chapter structuring command---for example, an @code{@@section} or @code{@@subsection} line. (@xref{Chapter Structuring}.) You should do this even if you do not intend to format the file for Info. This is because printed output uses both @code{@@node} names and chapter-structuring names in the output for cross-references. The only time you are likely to use the chapter structuring commands without also using nodes is if you are writing a document that contains no cross references and will only be printed, not transformed into Info, HTML, or other formats. @node Writing a Node @nodedescription How to write a @code{@@node} line. @section Writing a @code{@@node} Line @cindex Writing a @code{@@node} line @cindex @code{@@node} line writing @cindex Node line writing @findex node Write @code{@@node} at the beginning of a line followed by the name of the node, like this: @example @@node @var{node-name} @end example After you have inserted a @code{@@node} line, you should immediately write the @@-command for the associated chapter or section (if any) and insert its name. You may optionally follow the node name argument to @code{@@node} with up to three optional arguments on the rest of the same line, separating the arguments with commas. These are the names of the `Next', `Previous', and `Up' pointers, in that order. Hence, the template for a fully-written-out node line with `Next', `Previous', and `Up' pointers looks like this: @example @@node @var{node-name}, @var{next}, @var{previous}, @var{up} @end example The @var{node-name} argument must be present, but the others are optional. If you wish to specify some but not others, just insert commas as needed, as in: @samp{@@node mynode,,,uppernode}. Any spaces before or after each name on the @code{@@node} line are ignored. However, if your Texinfo document is hierarchically organized, as virtually all are, we recommend leaving off all the pointers and letting @code{texi2any} determine them. @cindex Creating pointers with @code{texi2any} @cindex Pointer creation with @code{texi2any} @cindex Automatic pointer creation with @code{texi2any} @cindex Implicit pointer creation with @code{texi2any} The @code{texi2any} program automatically determines node pointers for a hierarchically organized document. For it to do this, each @code{@@node} command should be followed immediately by a sectioning command such as @code{@@chapter} or @code{@@section} (except that comment lines may intervene). Finally, you must follow the `Top' @code{@@node} line with a line beginning with @code{@@top} to mark the top-level node in the file. @xref{@code{@@top} Command}. Even when you explicitly specify all pointers, you cannot write the nodes in the Texinfo source file in an arbitrary order. You must write the nodes in the order you wish them to appear in the output. For Info format one can imagine that the order may not matter, but it matters for the other formats. In most cases, you will want to take advantage of the pointer creation feature, and not redundantly specify node pointers that the programs can determine. However, Texinfo documents are not required to be organized hierarchically or in fact to contain sectioning commands at all (for example, if you never intend the document to be printed), so node pointers may still be specified explicitly, in full generality. If you are using GNU Emacs, and want explicit pointers, you can use the update node commands provided by Texinfo mode to insert the names of the pointers. (@xref{Updating Nodes and Menus}.) Alternatively, you can insert the `Next', `Previous', and `Up' pointers yourself. If you do this in Emacs, you may find it helpful to use the Texinfo mode keyboard command @kbd{C-c C-c n}. This command inserts @samp{@@node} and a comment line listing the names of the pointers in their proper order. The comment line helps you keep track of which arguments are for which pointers. @node Node Names @nodedescription How to choose node names. @section Choosing Node Names @cindex Node names, choosing The name of a node identifies the node. For all the details of node names, @pxref{Node Line Requirements}). @anchor{Node Line Tips}@c previous node name Here are some suggestions for node names: @itemize @bullet @item Try to pick node names that are informative but short. In the Info file, the file name, node name, and pointer names are all inserted on one line, which may run into the right edge of the window. (This does not cause a problem with Info, but is ugly.) @item Try to pick node names that differ from each other near the beginnings of their names. This way, it is easy to use automatic name completion in Info. @item Conventionally, node names are capitalized in the same way as section and chapter titles. In this manual, initial and significant words are capitalized; others are not. In other manuals, just initial words and proper nouns are capitalized. Either way is fine; we recommend just being consistent. @item In HTML output, any characters in the node name other than plain ASCII letters, numbers or spaces will be changed in the file name. (@xref{HTML Xref Node Name Expansion}.) This can make the URLs for the pages in your manual less user-friendly; for example, in this manual the @samp{@@dots} node is output as @file{__0040dots.html}. @end itemize Because node names are used in cross-references, it is not desirable to casually change them once published. When you delete or rename a node, it is usually a good idea to define an @code{@@anchor} with the old name. That way, references from other manuals, from mail archives, and so on are not invalidated. @xref{@code{@@anchor}}. The pointers from a given node enable you to reach other nodes and consist simply of the names of those nodes. Normally, a node's `Up' pointer contains the name of the node whose menu mentions that node. The node's `Next' pointer contains the name of the node that follows the present node in that menu and its `Previous' pointer contains the name of the node that precedes it in that menu. When a node's `Previous' node is the same as its `Up' node, both pointers name the same node. Usually, the first node of a Texinfo file is the `Top' node, and its `Up' pointer points to the @file{dir} file, which contains the main menu for all of Info. @node Node Line Requirements @nodedescription Keep names unique. @section @code{@@node} Line Requirements @cindex Node line requirements @cindex Restrictions on node names Names used with @code{@@node} have several requirements: @itemize @bullet @item @cindex Unique node names requirement @cindex Node names must be unique All the node names in a single Texinfo file must be unique. This means, for example, that if you end every chapter with a summary, you must name each summary node differently. You cannot just call them all ``Summary''. You may, however, duplicate the titles of chapters, sections, and the like. Thus you can end each chapter with a section called ``Summary'', so long as the node names for those sections are all different. Node names, anchor names (@pxref{@code{@@anchor}}), and float labels (@pxref{@code{@@float}}) must all be unique. @item @cindex Commands in node names @cindex @sortas{at} @@-commands @subentry in node names Node names can contain @@-commands@footnote{Prior to the Texinfo 5 release in 2013, this feature was supported in an ad hoc way (the @option{--commands-in-node-names} option to @command{makeinfo}). Now it is part of the language. }. For example, using @code{@@TeX@{@}} in a node name results in the @TeX{} logo being output, as it would be in normal text. Cross-references should use @code{@@TeX@{@}} just as the node name does. Some commands do not make sense in node names; for instance, environments (e.g., @code{@@quotation}), commands that read a whole line as their argument (e.g., @code{@@sp}), and plenty of others. For the complete list of commands that are allowed, and their expansion for HTML identifiers and file names, @pxref{HTML Xref Command Expansion}. @item @cindex Parentheses in node name A node name may not start with a left parenthesis preceding a right parenthesis, as in @code{(not)allowed}, since this syntax is used to specify an external manual. @item @cindex Colon in node name @cindex Comma in node name @cindex Period in node name @cindex Characters, invalid in node name @cindex Invalid characters in node names @cindex Node names, invalid characters in @anchor{Info Node Names Constraints} Unfortunately, you cannot reliably use periods, commas, or colons within a node name; these can confuse some Info readers. @command{texi2any} quotes problematic node names and labels by default, but some Info readers do not recognize this syntax. Node name and label quoting causes @code{DEL} characters (@samp{CTRL-?}, character number 127, often rendered as @samp{^?}) to appear around the name. To remove node names and labels quoting, you can set the customization variable @code{INFO_SPECIAL_CHARS_QUOTE} to @samp{0} (@pxref{Other Customization Variables}). @command{texi2any} warns about such problematic usage in node names, menu items, and cross-references. If you don't want to see the warnings, you can set the customization variable @code{INFO_SPECIAL_CHARS_WARNING} to @samp{0} (@pxref{Other Customization Variables}). If you insist on using these characters in node names, in order not to confuse the Texinfo processors you must still escape those characters, by using either special insertions (@pxref{Inserting a Comma}) or @code{@@asis} (@pxref{@code{@@asis}}). For example: @example @@node foo@@asis@{::@}bar@@comma@{@} baz @end example As an example of avoiding the special characters, the following is a section title in this manual: @example @@section @@code@{@@@@unnumbered@}, @@code@{@@@@appendix@}: Chapters with@enddots{} @end example @noindent But the corresponding node name lacks the commas and the subtitle: @example @@node @@code@{@@@@unnumbered @@@@appendix@} @end example @cindex Case in node name @item Case is significant in node names. @cindex White space in node name @cindex Spaces in node name @item Spaces before and after names on the @samp{@@node} line are ignored. Multiple whitespace characters ``inside'' a name are collapsed to a single space. For example: @example @@node foo bar @@node foo bar, @@node foo bar , @@node foo bar, @@node foo bar , @end example @c Consistently with the HTML Cross-reference Node Name Expansion @c spaces and newlines generated by @-commands should also be @c collapsed to a single space. If we wanted to be explicit, we @c could have added a line corresponding to @c @node @ foo @: @* bar, @c However, it is best to leave those special cases non documented @noindent all define the same node, namely @samp{foo bar}. @c FIXME to be removed. In 2022 both Info readers find the node. In menu entries, a single internal space should be used in node names or some versions of some Info readers will not find the node. @end itemize @node First Node @nodedescription How to write a `Top' node. @section The First Node @cindex Top node is first @cindex First node The first node of a Texinfo file is the @dfn{Top} node, except in an included file (@pxref{Include Files}). The Top node should contain a short summary and a master menu. @xref{The Top Node} for more information on the Top node contents and examples. Straight text before the Top node outside of any node should be avoided. Such text, if present, is not output for DocBook. Here is a description of the node pointers to be used in the Top node: @itemize @bullet @item @cindex Up node of Top node @cindex (dir) as Up node of Top node The Top node (which must be named @samp{top} or @samp{Top}) should have as its `Up' node the name of a node in another file, where there is a menu that leads to this file. Specify the file name in parentheses. Usually, all Info files are available through a single virtual Info tree, constructed from multiple directories. In this case, use @samp{(dir)} as the parent of the Top node; this specifies the top-level node in the @file{dir} file, which contains the main menu for the Info system as a whole. (Each directory with Info files is intended to contain a file named @file{dir}.) That's fine for Info, but for HTML output, one might well want the Up link from the Top node to go to some specific place. For example, for GNU the natural place would be @url{http://www.gnu.org/manual/} (a web page collecting links to most GNU manuals), better specified as just @code{/manual/} if the manual will be installed on @code{www.gnu.org}. This can be specified with the @code{TOP_NODE_UP_URL} customization variable (@pxref{HTML Customization Variables}), as in @example $ @kbd{texi2any --html -c TOP_NODE_UP_URL=/manual/} ... @end example @c the following line is not true anymore @c All links to @code{(dir)} will be replaced by the given url. @item @cindex Prev node of Top node The `Prev' node of the Top node is usually omitted. @item @cindex Next node of Top node The `Next' node of the Top node should be the first chapter in your document. @end itemize @xref{Installing an Info File}, for more information about installing an Info file in the @file{info} directory. It is usually best to leave the pointers off entirely and let the tools implicitly define them, with this simple result: @example @@node Top @end example @node @code{@@top} Command @nodedescription How to use the @code{@@top} command. @section The @code{@@top} Sectioning Command @anchor{top command}@c old name @anchor{makeinfo top}@c another old name @anchor{makeinfo top command}@c yet another name @findex top The @code{@@top} command is a special sectioning command that you should only use after a @samp{@@node Top} line at the beginning of a Texinfo file. It produces the same sort of output as @code{@@unnumbered} (@pxref{@code{@@unnumbered @@appendix}}). In @LaTeX{} @code{\part*} is used. @code{@@top} is ignored when raising or lowering sections. That is, it is never lowered and nothing can be raised to it (@pxref{Raise/lower sections}). It used to be conventional to wrap the @samp{Top} node in an @code{@@ifnottex} conditional so that it would not appear in printed output (@pxref{Conditionals}). Thus, a Top node often looked like this: @example @@ifnottex @@node Top @@top @var{your-manual-title} @var{very-high-level-summary} @@end ifnottex @end example This is no longer necessary, as the @samp{Top} node is now never output for printed output. The @samp{Top} node is not output for DocBook either. @node Texinfo Document Structure @nodedescription Double structure of documents. @section Texinfo Document Structure @cindex Texinfo document structure @cindex Document structure, of Texinfo @cindex Structure, of Texinfo documents @cindex Double structure, of Texinfo documents @anchor{Two Paths}@c old node name Nodes can contain @dfn{menus}, which contain the names of @dfn{child nodes} within the parent node; for example, a node corresponding to a chapter would have a menu of the sections in that chapter. The menus allow the user to move to the child nodes in the Info output. In addition, nodes contain @dfn{node pointers} that name other nodes. The `Next' and `Previous' pointers link nodes at the same sectioning level into a chain. As you might imagine, the `Next' pointer links to the next node, and the `Previous' pointer links to the previous node. In general, `Next' and `Previous' refer to nodes at the @emph{same hierarchical level} in the manual, not necessarily to the next node within the Texinfo file. In the Texinfo file, the subsequent node may be at a lower level---a section-level node most often follows a chapter-level node, for example. Thus, for example, all the nodes that are at the level of sections within a chapter are linked together, and the order in this chain is the same as the order of the children in the menu of the parent chapter. Each child node records the parent node name as its `Up' pointer. Since the `Top' node is the only node at that level, `Next' refers to the first following node, which is almost always a chapter or chapter-level node. This is an exception to the rule of `Next' being at the same hierarchical level. @cindex @code{accesskey} @subentry in HTML output of nodes The Info and HTML output for each node includes links to the `Next', `Previous', and `Up' nodes. The HTML also uses the @code{accesskey} attribute with the values @samp{n}, @samp{p}, and @samp{u} respectively. This allows people using web browsers to follow the navigation using (typically) @kbd{M-@var{letter}}, e.g., @kbd{M-n} for the `Next' node, from anywhere within the node. Node pointers and menus provide structure for Info files just as chapters, sections, subsections, and the like provide structure for printed books. The two structures are theoretically distinct; in practice, however, the tree structure of printed books is essentially always used for the node and menu structure also, as this leads to a document which is easy to follow. Typically, the sectioning structure and the node structure are completely parallel, with one node for each chapter, section, etc., and with the nodes following the same hierarchical arrangement as the sectioning. Thus, if a node is at the logical level of a chapter, its child nodes are at the level of sections; similarly, the child nodes of sections are at the level of subsections. It is technically possible to create Texinfo documents with only one structure or the other, or for the two structures not to be parallel, or for either the sectioning or node structure to be different from the conventional structure. To the best of our knowledge, however, all the Texinfo manuals currently in general use do follow the conventional parallel structure. @node Node Menu Illustration @nodedescription A diagram, and sample nodes and menus. @section Node and Menu Illustration Here is a diagram that illustrates a Texinfo file with three chapters, each of which contains two sections. The ``root'' is at the top of the diagram and the ``leaves'' are at the bottom. This is how such a diagram is drawn conventionally; it illustrates an upside-down tree. For this reason, the root node is called the `Top' node, and `Up' node pointers carry you closer to the root. @example @group Top | ------------------------------------- | | | Chapter 1 Chapter 2 Chapter 3 | | | -------- -------- -------- | | | | | | Section Section Section Section Section Section 1.1 1.2 2.1 2.2 3.1 3.2 @end group @end example Using explicit pointers (not recommended, but shown for purposes of the example), the fully-written command to start Chapter@tie{}2 would be this: @example @group @@node Chapter 2, Chapter 3, Chapter 1, Top @@comment node-name, next, previous, up @end group @end example @noindent This @code{@@node} line says that the name of this node is ``Chapter@tie{}2'', the name of the `Next' node is ``Chapter 3'', the name of the `Previous' node is ``Chapter@tie{}1'', and the name of the `Up' node is ``Top''. You can (and should) omit writing out these node names if your document is hierarchically organized, but the pointer relationships still obtain. To go to Sections 2.1 and 2.2 using Info, you need a menu inside Chapter 2. (@xref{Menus}.) You would write the menu just before the beginning of Section 2.1, like this: @example @group @@menu * Sect. 2.1:: Description of this section. * Sect. 2.2:: Description. @@end menu @end group @end example The automatic pointers for the node for Sect.@: 2.1 correspond to: @example @group @@node Sect. 2.1, Sect. 2.2, , Chapter 2 @@comment node-name, next, previous, up @end group @end example Note that no `Prev' pointer is generated, since there is no other node at the same hierarchical level before Sect.@: 2.1. Using explicit pointers, the node for Sect.@: 2.1 could be written like this: @example @group @@node Sect. 2.1, Sect. 2.2, Chapter 2, Chapter 2 @@comment node-name, next, previous, up @end group @end example With automatic pointers, the `Next' and `Previous' pointers of a node lead to other nodes at the same level---from chapter to chapter or from section to section. As shown, when using explicit pointers, the pointers can also lead somewhere else, here, for example, the `Previous' pointer points up. An `Up' pointer usually leads to a node at the level above (closer to the `Top' node; and a `Menu' leads to nodes at a level below (closer to `leaves'). (A cross-reference can point to a node at any level; see @ref{Cross References}.) Technically, explicit node pointers can carry you to any node, regardless of the structure of the document; even to nodes in a different Info file. However, it would be very confusing for readers to have the `Next', `Previous' and `Up' pointers lead to nodes that do not correspond, even loosely, to the next, previous and up node. A @code{@@node} command and a chapter structuring command are conventionally used together, in that order, often followed by indexing commands. (As shown in the example above, you may follow the @code{@@node} line with a comment line, e.g., to show which pointer is which if explicit pointers are used.) The Texinfo processors use this construct to determine the relationships between nodes and sectioning commands. Here is the beginning of the chapter in this manual called ``Ending a Texinfo File''. This shows a @code{@@node} line followed by a @code{@@chapter} line, and then by indexing lines. @example @group @@node Ending a File @@chapter Ending a Texinfo File @@cindex Ending a Texinfo file @@cindex Texinfo file ending @@cindex File ending @end group @end example @node Node Descriptions @nodedescriptionblock @code{@@nodedescription} and @code{@@nodedescriptionblock}. @end nodedescriptionblock @section Node Descriptions @findex nodedescription You can provide a short description of the purpose of a node by using the @code{@@nodedescription} command following the @code{@@node} line. Such a description might elaborate on or extend the information in the node name itself. @findex nodedescriptionblock You can also use a @code{@@nodedescriptionblock} environment to provide a node description. This may be useful for longer descriptions. @command{texi2any} uses the content you provide with these commands when outputing menus for Info output format (and, optionally, for HTML). @command{texi2any} uses the description after a menu entry for the node if it is generating the menu automatically, or if no description for the menu entry was provided in an explicit @code{@@menu} block. (@xref{Menus}). Here is an example of using these commands: @example @@node Tools @@chapter Tools This chapter is on different tools you can use. @@node Screwdrivers @@nodedescription Flathead and Phillips. @@section Screwdrivers This section is about screwdrivers. @@node Drills @@nodedescriptionblock Making holes in things with power screwdrivers, drill drivers, combi drills, impact drivers, hammer drills, breakers and demolition drills. @@end nodedescriptionblock @@section Drills This section is about drills. @end example In Info output, @command{texi2any} would output the @samp{Tools} node with a menu as follows: @example * Menu: * Screwdrivers:: Flathead and Phillips. * Drills:: Making holes in things with power screwdrivers, drill drivers, combi drills, impact drivers, hammer drills, breakers and demolition drills. @end example @node Menus @nodedescription Listing subordinate nodes. @section Menus @cindex Menus @findex menu @dfn{Menus} contain pointers to subordinate nodes. In Info output, you use menus to go to such nodes. @command{texi2any} can output menus in HTML output, but does not do so by default (@pxref{Other Customization Variables}, under @code{FORMAT_MENU}). Menus have no role in printed manuals or other output formats. Menus are automatically generated by @command{texi2any} when outputting Info for nodes followed by a sectioning command, without an explicit @code{@@menu} block, and with automatic pointers. It is often more convenient to let @command{texi2any} generate menus for you, as you do not then have the burden of updating menu blocks in your Texinfo source when you add, remove, or relocate nodes. In the usual case of a hierarchically organized manual with sectioning commands associated with nodes, and with node pointers left out, you should only write menus if you want exact control over the contents and formatting of menus in Info. @node Writing a Menu @nodedescription What is a menu? @subsection Writing a Menu @cindex Writing a menu @cindex Menu writing A menu consists of a @code{@@menu} command on a line by itself, followed by menu entry lines or menu comment lines, and then followed by an @code{@@end menu} command on a line by itself. A menu looks like this: @example @group @@menu Larger Units of Text * Files:: All about handling files. * Multiples: Buffers. Multiple buffers; editing several files at once. @@end menu @end group @end example @cindex Spaces, in menus In a menu, every line that begins with an @w{@samp{* }} is a @dfn{menu entry}. (Note the space after the asterisk.) A line that does not start with an @w{@samp{* }} may also appear in a menu. Such a line is not a menu entry but rather a @dfn{menu comment} line that appears in the Info file. In the example above, the line @samp{Larger Units of Text} is such a menu comment line; the two lines starting with @w{@samp{* }} are menu entries. @cindex Hierarchical documents, and menus Technically, menus can carry you to any node, regardless of the structure of the document; even to nodes in a different Info file. However, the @command{texi2any} implicit pointer creation feature (@pxref{Writing a Node}) and GNU Emacs Texinfo mode updating commands work only to create menus of subordinate nodes in a hierarchically structured document. In a hierarchically structured document, it is much better to use cross-references to refer to arbitrary nodes. In Info, a user selects a node with the @kbd{m} (@code{Info-menu}) command. The menu entry name is what the user types after the @kbd{m} command. @cindex @code{accesskey} @subentry in HTML output of menus In the HTML output, the @code{accesskey} attribute is used with the values @samp{1}@dots{}@samp{9} for the first nine entries. This allows people using web browsers to follow the first menu entries using (typically) @kbd{M-@var{digit}}, e.g., @kbd{M-1} for the first entry. @node Menu Example @nodedescription Two and three part menu entries. @subsection A Menu Example @cindex Menu example @cindex Example menu @c merge with Writing a Menu node? A menu looks like this in Texinfo: @example @group @@menu * menu entry name: Node name. A short description. * Node name:: This form is preferred. @@end menu @end group @end example @need 800 @noindent This produces: @example @group * Menu: * menu entry name: Node name. A short description. * Node name:: This form is preferred. @end group @end example @need 700 Here is an example as you might see it in a Texinfo file: @example @group @@menu Larger Units of Text * Files:: All about handling files. * Multiples: Buffers. Multiple buffers; editing several files at once. @@end menu @end group @end example @need 800 @noindent This produces: @example @group * Menu: Larger Units of Text * Files:: All about handling files. * Multiples: Buffers. Multiple buffers; editing several files at once. @end group @end example In this example, the menu has two entries. @samp{Files} is both a menu entry name and the name of the node referred to by that name. @samp{Multiples} is the menu entry name; it refers to the node named @samp{Buffers}. The line @samp{Larger Units of Text} is a comment; it appears in the menu, but is not an entry. Since no file name is specified with either @samp{Files} or @samp{Buffers}, they must be the names of nodes in the same Info file (@pxref{Other Info Files, , Referring to Other Info Files}). @node Menu Location @nodedescription Menus go at the ends of nodes. @subsection Menu Location @cindex Menu location @cindex Location of menus There may be at most one menu in a node. A menu is conventionally located at the end of a node, without any regular text or additional commands between the @code{@@end menu} and the beginning of the next node. @cindex Info format, and menus This convention is useful, since a reader who uses the menu could easily miss any such text. Also, any such post-menu text will be considered part of the menu in Info output (which has no marker for the end of a menu). Thus, a line beginning with @samp{* } will likely be incorrectly handled. It's usually best if a node with a menu does not contain much text. If you find yourself with a lot of text before a menu, we generally recommend moving all but a couple of paragraphs into a new subnode. Otherwise, it is easy for readers to miss the menu. @node Menu Parts @nodedescription A menu entry has three parts. @subsection The Parts of a Menu @cindex Parts of a menu @cindex Menu parts @cindex @code{@@menu} parts A menu entry has three parts, only the second of which is required: @enumerate @item The menu entry name (optional). @item The name of the node (required). @item A description of the item (optional). @end enumerate The template for a generic menu entry looks like this (but see the next section for one more possibility): @example * @var{menu-entry-name}: @var{node-name}. @var{description} @end example Follow the menu entry name with a single colon, and follow the node name with tab, comma, newline, or the two characters period and space (@samp{. }). The third part of a menu entry is a descriptive phrase or sentence. Menu entry names and node names are often short; the description explains to the reader what the node is about. A useful description complements the node name rather than repeats it. The description, which is optional, can spread over multiple lines; if it does, some authors prefer to indent the second line while others prefer to align it with the first (and all others). It's up to you. An empty line, or the next menu entry, ends a description. Space characters in a menu are preserved as-is in the Info output; this allows you to format the menu as you wish. @c FIXME to be removed. In 2022 both Info readers find the node. Unfortunately you must type node names without any extra spaces or some versions of some Info readers will not find the node (@pxref{Node Line Requirements}). @command{texi2any} warns and protect names when the text of a menu item (and node names and cross-references) contains a problematic construct that could interfere with its parsing in Info. @xref{Info Node Names Constraints}. @node Less Cluttered Menu Entry @nodedescription Two part menu entry. @subsection Less Cluttered Menu Entry @cindex Two part menu entry @cindex Double-colon menu entries @cindex Menu entries with two colons @cindex Less cluttered menu entry @cindex Uncluttered menu entry When the menu entry name and node name are the same, you can write the name immediately after the asterisk and space at the beginning of the line and follow the name with two colons. @need 800 For example, write @set txicodevaristt @example * Name:: @var{description} @end example @need 800 @noindent instead of @example * Name: Name. @var{description} @end example We recommend using the node name for the menu entry name whenever possible, since it reduces visual clutter in the menu. @node Other Info Files @nodedescription How to refer to a different Info file. @subsection Referring to Other Info Files @cindex Referring to other Info files @cindex Nodes in other Info files @cindex Other Info files' nodes @cindex Going to other Info files' nodes @cindex Info; other files' nodes You can create a menu entry that enables a reader in Info to go to a node in another Info file by writing the file name in parentheses just before the node name. Some examples: @example @group @@menu * @var{first-entry-name}:(@var{filename})@var{nodename}. @var{description} * (@var{filename})@var{second-node}:: @var{description} @@end menu @end group @end example @clear txicodevaristt For example, to refer directly to the @samp{Outlining} and @samp{Rebinding} nodes in the @cite{Emacs Manual}, you could write a menu like this: @example @group @@menu * Outlining: (emacs)Outline Mode. The major mode for editing outlines. * (emacs)Rebinding:: How to redefine the meaning of a key. @@end menu @end group @end example If you do not list the node name, but only name the file, then Info presumes that you are referring to the `Top' node. Examples: @example @group * Info: (info). Documentation browsing system. * (emacs):: The extensible, self-documenting text editor. @end group @end example The GNU Emacs Texinfo mode menu updating commands only work with nodes within the current buffer, so you cannot use them to create menus that refer to other files. You must write such menus by hand. @xref{Updating Nodes and Menus}. @node Chapter Structuring @nodedescription Creating chapters, sections, appendices, etc. @chapter Chapter Structuring @anchor{Structuring}@c old name @cindex Chapter structuring @cindex Structuring of chapters @cindex Sectioning Texinfo's @dfn{chapter structuring} commands divide a document into a hierarchy of chapters, sections, subsections, and subsubsections. These commands generate large headings in the text, like the one above. They also provide information for generating the table of contents (@pxref{Contents,, Generating a Table of Contents}). Normally you put a @code{@@node} command immediately before each chapter structuring command. @xref{Nodes}. @node Tree Structuring @nodedescription A manual is like an upside down tree @dots{} @section Tree Structure of Sections @cindex Tree structuring A Texinfo file is usually structured like a book with chapters, sections, subsections, and the like. This structure can be visualized as a tree (or rather as an upside-down tree) with the root at the top and the levels corresponding to chapters, sections, subsection, and subsubsections. Here is a diagram that shows a Texinfo file with three chapters, each with two sections. @example @group Top | ------------------------------------- | | | Chapter 1 Chapter 2 Chapter 3 | | | -------- -------- -------- | | | | | | Section Section Section Section Section Section 1.1 1.2 2.1 2.2 3.1 3.2 @end group @end example In a Texinfo file that has this structure, the beginning of Chapter 2 would be written like this: @example @group @@node Chapter 2 @@chapter Chapter 2 @end group @end example @noindent For purposes of example, here is how it would be written with explicit node pointers: @example @group @@node Chapter 2, Chapter 3, Chapter 1, Top @@chapter Chapter 2 @end group @end example The chapter structuring commands are described in the sections that follow; the @code{@@node} command is described in the previous chapter (@pxref{Nodes}). @node Structuring Command Types @section Structuring Command Types The chapter structuring commands fall into four groups, each of which contains structuring commands at the levels of chapters, sections, subsections, and subsubsections: @itemize @bullet @item The @code{@@chapter}-like commands and @code{@@appendix}-like commands produce numbered or lettered entries both in the body of a document and in its table of contents. @item The @code{@@unnumbered}-like commands produce unnumbered entries both in the body of a document and in its table of contents. The @code{@@top} command, which has a special use, is a member of this group (@pxref{@code{@@top} Command}). An @code{@@unnumbered} section is a normal part of the document structure. @item The @code{@@heading}-like commands produce simple unnumbered headings that do not appear in a table of contents, are not associated with nodes, and cannot be cross-referenced. These heading commands never start a new page. @end itemize In printed output, the chapter structuring commands produce headings in the document. When a @code{@@setchapternewpage} command says to do so, the @code{@@chapter}, @code{@@unnumbered}, and @code{@@appendix} commands start new pages in the printed manual; the @code{@@heading} commands do not. @xref{@code{@@setchapternewpage}}. In Info and plain text output, the command causes the title to appear on a line by itself, with a line of an ASCII character (@samp{*}, @samp{=}, @dots{}) inserted underneath. For example, the ``Chapter Structuring'' heading could be: @example @group 5 Chapter Structuring ********************* @end group @end example @noindent The underlining character is the same for all the commands at the same level. For instance, it is the same for the chapter-level commands @code{@@chapter}, @code{@@apppendix}, @code{@@unnumbered} and @code{@@chapheading}. In HTML, the chapter-level commands produce an @code{<h2>}-level header by default (controlled by the @code{CHAPTER_HEADER_LEVEL} customization variable, @pxref{Other Customization Variables}). The heading element level is adjusted for the other commands. In the DocBook output, the appropriate level of element is used. The produced element includes all following sections up to the next command at the same or higher level. For example, a @code{<chapter>} element is produced for @code{@@chapter}, and contains any sections or subsections in the chapter. Here is a summary: @tex {\globaldefs=1 \smallfonts \rm} @end tex @multitable @columnfractions .19 .30 .29 .22 @item @tab @tab @tab No new page @item @i{Numbered} @tab @i{Unnumbered} @tab @i{Lettered/numbered} @tab @i{Unnumbered} @item In contents @tab In contents @tab In contents @tab Not in contents @item @tab @code{@@top} @tab @tab @code{@@majorheading} @item @code{@@chapter} @tab @code{@@unnumbered} @tab @code{@@appendix} @tab @code{@@chapheading} @item @code{@@section} @tab @code{@@unnumberedsec} @tab @code{@@appendixsec} @tab @code{@@heading} @item @code{@@subsection} @tab @code{@@unnumberedsubsec} @tab @code{@@appendixsubsec} @tab @code{@@subheading} @item @code{@@subsubsection} @tab @code{@@unnumberedsubsubsec} @tab @code{@@appendixsubsubsec} @tab @code{@@subsubheading} @end multitable @tex {\globaldefs=1 \textfonts \rm} @end tex @node @code{@@chapter} @section @code{@@chapter}: Chapter Structuring @anchor{chapter}@c old name @findex chapter @code{@@chapter} identifies a chapter in the document--the highest level of the normal document structuring hierarchy. Write the command at the beginning of a line and follow it on the same line by the title of the chapter. The chapter is numbered automatically, starting from@tie{}1. For example, the present chapter in this manual is entitled ``Chapter Structuring''; the @code{@@chapter} line looks like this: @example @@chapter Chapter Structuring @end example @node @code{@@unnumbered @@appendix} @section @code{@@unnumbered}, @code{@@appendix}: Chapters with Other Labeling @anchor{unnumbered & appendix}@c old name @findex unnumbered @findex appendix Use the @code{@@unnumbered} command to start a chapter-level element that appears without chapter numbers of any kind. Use the @code{@@appendix} command to start an appendix that is labeled by letter (`A', `B', @dots{}) instead of by number; appendices are also at the chapter level of structuring. Write an @code{@@appendix} or @code{@@unnumbered} command at the beginning of a line and follow it on the same line by the title, just as with @code{@@chapter}. @findex centerchap Texinfo also provides a command @code{@@centerchap}, which is analogous to @code{@@unnumbered}, but centers its argument in the printed and HTML outputs. This kind of stylistic choice is not usually offered by Texinfo. @c but the Hacker's Dictionary wanted it, before they quit Texinfo. You are recommended not to use this command, as it may be removed in future releases of Texinfo. @cindex DocBook and prefatory sections @cindex Preface, etc., and DocBook With @code{@@unnumbered}, if the name of the associated node is one of these English words (case-insensitive): @example Acknowledgements Colophon Dedication Preface @end example @cindex @code{<acknowledgements>} DocBook tag @cindex @code{<colophon>} DocBook tag @cindex @code{<dedication>} DocBook tag @cindex @code{<preface>} DocBook tag @cindex @code{<chapter>} DocBook tag @noindent then the DocBook output uses corresponding special tags (@code{<preface>}, etc.)@: instead of the default @code{<chapter>}. The argument to @code{@@unnumbered} itself can be anything, and is output as the element title as usual. @node @code{@@majorheading @@chapheading} @section @code{@@majorheading}, @code{@@chapheading}: Chapter-level Headings @anchor{majorheading & chapheading}@c old name @findex majorheading @findex chapheading The @code{@@majorheading} and @code{@@chapheading} commands produce chapter-like headings in the body of a document. However, neither command produces an entry in the table of contents, and neither command causes @TeX{} to start a new page in a printed manual. In @TeX{}, a @code{@@majorheading} command generates a larger vertical whitespace before the heading than a @code{@@chapheading} command but is otherwise the same. In other output formats, the @code{@@majorheading} and @code{@@chapheading} commands produce a similar output to @code{@@chapter}. The difference is the lack of numbering and the lack of any association with nodes. @xref{@code{@@chapter}}. @node @code{@@section} @section @code{@@section}: Sections Below Chapters @anchor{section}@c old name @findex section An @code{@@section} command identifies a section within a chapter unit, whether created with @code{@@chapter}, @code{@@unnumbered}, or @code{@@appendix}, following the numbering scheme of the chapter-level command. Thus, within a @code{@@chapter} chapter numbered `1', the sections are numbered `1.1', `1.2', etc.; within an @code{@@appendix} ``chapter'' labeled `A', the sections are numbered `A.1', `A.2', etc.; within an @code{@@unnumbered} chapter, the section gets no number. To make a section, write the @code{@@section} command at the beginning of a line and follow it on the same line by the section title. For example: @example @@section This is a section @end example Section titles are listed in the table of contents. @node @code{@@unnumberedsec @@appendixsec @@heading} @section @code{@@unnumberedsec}, @code{@@appendixsec}, @code{@@heading} @anchor{unnumberedsec appendixsec heading}@c old name @findex unnumberedsec @findex appendixsec @findex heading The @code{@@unnumberedsec}, @code{@@appendixsec}, and @code{@@heading} commands are, respectively, the unnumbered, appendix-like, and heading-like equivalents of the @code{@@section} command (see the previous section). @code{@@unnumberedsec} and @code{@@appendixsec} do not need to be used in ordinary circumstances, because @code{@@section} may also be used within @code{@@unnumbered} and @code{@@appendix} chapters; again, see the previous section. @table @code @item @@unnumberedsec The @code{@@unnumberedsec} command may be used within an unnumbered chapter or within a regular chapter or appendix to produce an unnumbered section. @findex appendixsection @item @@appendixsec @itemx @@appendixsection @code{@@appendixsection} is a longer spelling of the @code{@@appendixsec} command; the two are synonymous. Conventionally, the @code{@@appendixsec} or @code{@@appendixsection} command is used only within appendices. @item @@heading You may use the @code{@@heading} command (almost) anywhere for a section-style heading that will not appear in the table of contents. The @code{@@heading}-series commands can appear inside most environments, for example, though pathological and useless locations such as an argument to another command, etc., are not allowed. @end table @node @code{@@subsection} @section @code{@@subsection}: Subsections Below Sections @anchor{subsection}@c old name @findex subsection Subsections are to sections as sections are to chapters; @pxref{@code{@@section}}. For example: @example @@subsection This is a subsection @end example Subsection titles are listed in the table of contents. @node @code{@@unnumberedsubsec @@appendixsubsec @@subheading} @section The @code{@@subsection}-like Commands @anchor{unnumberedsubsec appendixsubsec subheading}@c old name @findex unnumberedsubsec @findex appendixsubsec @findex subheading @cindex Subsection-like commands The @code{@@unnumberedsubsec}, @code{@@appendixsubsec}, and @code{@@subheading} commands are, respectively, the unnumbered, appendix-like, and heading-like equivalents of the @code{@@subsection} command. (@xref{@code{@@subsection}}.) @code{@@unnumberedsubsec} and @code{@@appendixsubsec} do not need to be used in ordinary circumstances, because @code{@@subsection} may also be used within sections of @code{@@unnumbered} and @code{@@appendix} chapters (@pxref{@code{@@section}}). An @code{@@subheading} command produces a heading like that of a subsection except that it is not numbered and does not appear in the table of contents. Similarly, an @code{@@unnumberedsubsec} command produces an unnumbered heading like that of a subsection and an @code{@@appendixsubsec} command produces a subsection-like heading labeled with a letter and numbers; both of these commands produce headings that appear in the table of contents. @node @code{@@subsubsection} @section @code{@@subsubsection} and Other Subsub Commands @anchor{subsubsection}@c old name @findex subsubsection @findex unnumberedsubsubsec @findex appendixsubsubsec @findex subsubheading @cindex Subsub sectioning commands The fourth and lowest level sectioning commands in Texinfo are the `subsub' commands. They are: @table @code @item @@subsubsection Subsubsections are to subsections as subsections are to sections. (@xref{@code{@@subsection}}.) Subsubsection titles appear in the table of contents. @item @@unnumberedsubsubsec Unnumbered subsubsection titles appear in the table of contents, but lack numbers. Otherwise, unnumbered subsubsections are the same as subsubsections. @item @@appendixsubsubsec Conventionally, appendix commands are used only for appendices and are lettered and numbered appropriately. They also appear in the table of contents. @item @@subsubheading The @code{@@subsubheading} command may be used anywhere that you want a small heading that will not appear in the table of contents. @end table As with subsections, @code{@@unnumberedsubsubsec} and @code{@@appendixsubsubsec} do not need to be used in ordinary circumstances, because @code{@@subsubsection} may also be used within subsections of @code{@@unnumbered} and @code{@@appendix} chapters (@pxref{@code{@@section}}). @node @code{@@part} @nodedescription Collections of chapters. @section @code{@@part}: Groups of Chapters @findex part @cindex Part pages The final sectioning command is @code{@@part}, to mark a @dfn{part} of a manual, that is, a group of chapters or (rarely) appendices. This behaves quite differently from the other sectioning commands, to fit with the way such ``parts'' are conventionally used in books. No @code{@@node} command is associated with @code{@@part}. Just write the command on a line by itself, including the part title, at the place in the document you want to mark off as starting that part. For example: @example @@part Part I:@@* The beginning @end example As can be inferred from this example, no automatic numbering or labeling of the @code{@@part} text is done. The text is taken as-is. Because parts are not associated with nodes, no general text can follow the @code{@@part} line. To produce the intended output, it must be followed by a chapter-level command (including its node). Thus, to continue the example: @example @@part Part I:@@* The beginning @@node Introduction @@chapter Introduction ... @end example In the @TeX{} output, the @code{@@part} text is included in both the normal and short tables of contents (@pxref{Contents}), without a page number (since that is the normal convention). In addition, a ``part page'' is output in the body of the document, with just the @code{@@part} text. In the example above, the @code{@@*} causes a line break on the part page (but is replaced with a space in the tables of contents). This part page is always forced to be on an odd (right-hand) page, regardless of the chapter pagination (@pxref{@code{@@setchapternewpage}}). In the @LaTeX{} output, the @code{@@part} is output as @code{\part}. In the HTML output, the @code{@@part} text is similarly included in the tables of contents, and a heading is included in the main document text, as part of the following chapter or appendix node. In the DocBook output, the @code{<part>} element includes all the following chapters, up to the next @code{<part>}. A @code{<part>} containing chapters is also closed at an appendix. In the Info and plain text output, @code{@@part} has no effect. @code{@@part} is ignored when raising or lowering sections (see next section). That is, it is never lowered and nothing can be raised to it. @node Raise/lower sections @nodedescription How to change commands' hierarchical level. @section Raise/lower Sections: @code{@@raisesections} and @code{@@lowersections} @findex raisesections @findex lowersections @cindex Raising and lowering sections @cindex Lowering and raising sections @cindex Sections, raising and lowering The @code{@@raisesections} and @code{@@lowersections} commands implicitly raise and lower the hierarchical level of following chapters, sections and the other sectioning commands (excluding parts). That is, the @code{@@raisesections} command changes sections to chapters, subsections to sections, and so on. Conversely, the @code{@@lowersections} command changes chapters to sections, sections to subsections, and so on. Thus, a @code{@@lowersections} command cancels a @code{@@raisesections} command, and vice versa. @cindex Include files, and section levels As a practical matter, you generally only want to raise or lower large chunks, usually in external files. You can use @code{@@lowersections} to include text written as an outer or standalone Texinfo file in another Texinfo file as an inner, included file (@pxref{Include Files}). Typical usage looks like this: @example @@lowersections @@include somefile.texi @@raisesections @end example @noindent (Without the @code{@@raisesections}, all the subsequent sections in the main file would also be lowered.) If the included file being lowered has a @code{@@top} node, you'll need to conditionalize its inclusion with a flag (@pxref{@code{@@set @@value}}). Any menus in the final result have to take the raising and lowering into account, so arbitrarily sprinkling @code{@@raisesections} and @code{@@lowersections} commands throughout the document will likely lead to errors (unless the menus in your document are all generated automatically). Repeated use of the commands continues to raise or lower the hierarchical level a step at a time. An attempt to raise above `chapter' reproduces chapter commands; an attempt to lower below `subsubsection' reproduces subsubsection commands. Also, lowered subsubsections and raised chapters will not work with @command{texi2any}'s feature of implicitly determining node pointers, since the menu structure cannot be represented correctly. Write each @code{@@raisesections} and @code{@@lowersections} command on a line of its own. @node Cross References @nodedescription Writing cross-references. @chapter Cross-references @cindex Making cross-references @cindex Cross-references @cindex References @dfn{Cross-references} are used to refer the reader to other parts of the same or different Texinfo files. Use cross-references to provide access to information that is too detailed for the current context, or incidental to it. An online help system or a reference manual is not like a novel; few read such documents in sequence from beginning to end. Instead, people look up what they need. For this reason, such creations should contain many cross-references to help readers find other information that they may not have read. In a printed manual, a cross-reference results in a page reference, unless it is to another manual altogether, in which case the cross-reference names that manual. In Info, a cross-reference results in an entry that you can follow using the Info @samp{f} command. (@xref{Help-Xref,, Following cross-references, info, Info}.) In HTML, a cross-reference results in an hyperlink. In DocBook, the @code{<link>} element is used for cross-references unless it is to another manual, in which case the cross-reference names that manual. The various cross-reference commands use nodes, anchors (@pxref{@code{@@anchor}}) or float labels (@pxref{@code{@@float}}) to define cross-reference locations. When @TeX{} generates a DVI file, it records each cross-reference location page number and uses the page numbers in making references. Thus, even if you are writing a manual that will only be printed, and not used online, you must nonetheless write @code{@@node} lines (or @code{@@anchor} anchors) in order to name the places to which you make cross-references. @node Cross Reference Commands @nodedescription A summary of the different commands. @section Different Cross-reference Commands @cindex Different cross-reference commands There are three different cross-reference commands: @table @code @item @@xref Used to start a sentence with an Info cross-reference saying @samp{*Note @var{name}: @var{node}.} or with @w{`See @dots{}'} in other output formats. @item @@ref Used within or, more often, at the end of a sentence; produces an Info cross-reference saying @samp{*note @var{name}: @var{node}.}, and just the reference in other output formats, without the preceding `See'. @item @@pxref Used within parentheses, at the end of a sentence, or otherwise before punctuation, to make a reference. Its output starts with a lowercase @samp{*note} in Info, and with a lowercase `see' in the other output formats. (@samp{p} is for `parenthesis'.) @end table Additionally, there are commands to produce references to documents outside the Texinfo system. The @code{@@cite} command is used to make references to books and manuals. @code{@@url} produces a @acronym{URL}, for example a reference to a page on the World Wide Web. @node Cross Reference Parts @nodedescription A cross-reference has several parts. @section Parts of a Cross-reference @cindex Cross-reference parts @cindex Parts of a cross-reference @anchor{Reference Syntax} @c merged node A cross-reference command requires only one argument, which is the name of the node to which it refers. A cross-reference command may contain up to four additional arguments. The template for a full five argument cross-reference looks like this: @example @group @@xref@{@var{node-name}, @var{online-label}, @var{printed-label}, @var{manual-name}, @var{printed-manual-title}@} @end group @end example The five possible arguments for a cross-reference are: @enumerate @item The node or anchor name. This is the location to which the cross-reference takes you. In a printed document, the location of the node provides the page reference only for references within the same document. Use @code{@@node} to define the node (@pxref{Writing a Node}), @code{@@anchor} (@pxref{@code{@@anchor}}), or @code{@@float} (@pxref{@code{@@float}}) with a label. This argument is required (except for reference to whole manuals). Write a node name in a cross-reference in exactly the same way as in the @code{@@node} line, including the same capitalization; otherwise, the processors may not find the reference. @item A label for online output. It is usually omitted; then the topic description (third argument) is used if it was specified; if that was omitted as well, the node name is used. @item A label for printed output. Often, this is the title or topic of the section. This is used as the name of the reference in the printed manual. If omitted, the node name is used. @item The name of the manual to which the reference refers, if it is outside the current manual, in a different Texinfo file. @item The title of the printed manual to which the reference refers, from a different Texinfo file. @end enumerate Whitespace before and after the commas separating these arguments is ignored. To include a comma in one of the arguments, use @code{@@comma@{@}} (@pxref{Inserting a Comma}). Cross-references with one, two, three, four, and five arguments are described separately in following sections. @cindex Comma after cross-reference When processing with TeX, a comma is automatically inserted after the page number for cross-references to within the same manual, unless the closing brace of the argument is followed by non-whitespace (such as a comma or period). This gives you the choice of whether to have a comma there in other output formats. For example, @example @@xref@{Another Section@} for more info @end example @noindent with TeX produces @w{`See Another Section, page @var{ppp}, for more info'}, and in the Info output produces @w{@samp{*Note Another Section:: for more info}}. If an unwanted comma is added, follow the argument with a command such as @samp{@@:}. For example, @w{@samp{@@xref@{Hurricanes@}@@: --- for the details}} produces @quotation See Hurricanes, page @var{ppp} --- for the details @end quotation @noindent instead of @w{`See Hurricanes, page @var{ppp}, --- for the details'}. @command{texi2any} warns and protect names when the text of a cross-reference (and node names and menu items) contains a problematic construct that could interfere with its parsing in Info. @xref{Info Node Names Constraints}. @raisesections @node One Argument @nodedescription @code{@@xref} with one argument. @subsection @code{@@xref} with One Argument @cindex One-argument form of cross-references The simplest form of @code{@@xref} takes one argument, the name of another node in the same Texinfo file. @need 700 @noindent For example, @example @@xref@{Tropical Storms@}. @end example @noindent produces @example *Note Tropical Storms::. @end example @noindent in Info and @quotation See Section 3.1 [Tropical Storms], page 24. @end quotation @noindent in a printed manual. @node Two Arguments @nodedescription @code{@@xref} with two arguments. @subsection @code{@@xref} with Two Arguments @cindex Two-argument form of cross-references With two arguments, the second is used as a label for the online output. @need 750 @noindent The template is like this: @example @@xref@{@var{node-name}, @var{online-label}@}. @end example @need 700 @noindent For example, @example @@xref@{Electrical Effects, Lightning@}. @end example @noindent produces: @example *Note Lightning: Electrical Effects. @end example @noindent in Info and @quotation See Section 5.2 [Electrical Effects], page 57. @end quotation @noindent in a printed manual, where the node name is printed. The second argument to cross-references shares constraints with node names. The potentially problematic character in this context is the colon. @xref{Info Node Names Constraints}. @node Three Arguments @nodedescription @code{@@xref} with three arguments. @subsection @code{@@xref} with Three Arguments @cindex Three-argument form of cross-references A third argument replaces the node name in the printed output. The third argument should be the name of the section in the printed output, or else state the topic discussed by that section. @need 750 @noindent The template is like this: @example @group @@xref@{@var{node-name}, @var{online-label}, @var{printed-label}@}. @end group @end example @need 700 @noindent For example, @example @group @@xref@{Electrical Effects, Lightning, Thunder and Lightning@}, for details. @end group @end example @noindent produces @example *Note Lightning: Electrical Effects, for details. @end example @noindent in Info and @quotation See Section 5.2 [Thunder and Lightning], page 57, for details. @end quotation @noindent in a printed manual. If a third argument is given and the second one is empty, then the third argument serves for both. (Note how two commas, side by side, mark the empty second argument.) @example @group @@xref@{Electrical Effects, , Thunder and Lightning@}, for details. @end group @end example @noindent produces @example *Note Thunder and Lightning: Electrical Effects, for details. @end example @noindent in Info and @quotation See Section 5.2 [Thunder and Lightning], page 57, for details. @end quotation @noindent in a printed manual. The third argument to cross-references shares constraints with node names. The potentially problematic character in this context is the colon. @xref{Info Node Names Constraints}. As a practical matter, it is often best to write cross-references with just the first argument if the node name and the section title are the same (or nearly so), and with the first and third arguments only if the node name and title are different. @findex xrefautomaticsectiontitle Texinfo offers a setting to use the section title instead of node names by default in cross-references (an explicitly specified third argument still takes precedence): @example @@xrefautomaticsectiontitle on @end example Typically this line would be given near the beginning of the document and used for the whole manual. But you can turn it off if you want (@code{@@xrefautomaticsectiontitle off}), for example, if you're including some other sub-document that doesn't have suitable section names. This setting also applies to node headers in HTML, if @code{@@xrefautomaticsectiontitle} is on, the sections names are used in node headers instead of the node names when possible. @node Four and Five Arguments @nodedescription @code{@@xref} with four and five arguments. @subsection @code{@@xref} with Four and Five Arguments @cindex Four- and five argument forms of cross-references In a cross-reference, a fourth argument specifies the name of another manual, different from the file in which the reference appears, and a fifth argument specifies its title as a printed manual. @need 800 @noindent The full template is: @example @group @@xref@{@var{node-name}, @var{online-label}, @var{printed-label}, @var{manual-name}, @var{printed-manual-title}@}. @end group @end example @need 700 @noindent For example, @example @@xref@{Electrical Effects, Lightning, Thunder and Lightning, weather, An Introduction to Meteorology@}. @end example @noindent produces this output in Info: @example *Note Lightning: (weather)Electrical Effects. @end example @noindent As you can see, the name of the manual is enclosed in parentheses and precedes the name of the node. In HTML, the manual name and the node name are used to construct the hyperlink URL (@pxref{HTML Xref}), while the link text is based on the label. @noindent In a printed manual, the reference looks like this: @quotation See section ``Thunder and Lightning'' in @cite{An Introduction to Meteorology}. @end quotation @noindent The title of the printed manual is typeset like @code{@@cite}; and the reference lacks a page number since the page a reference refers when that reference is to another manual cannot be known. Next case: often, you will leave out the second argument when you use the long version of @code{@@xref}. In this case, the third argument, the topic description, will be used as the cross-reference name in online formats. For example, @example @@xref@{Electrical Effects, , Thunder and Lightning, weather, An Introduction to Meteorology@}. @end example @noindent produces @example @group *Note Thunder and Lightning: (weather)Electrical Effects. @end group @end example @noindent in Info and @quotation See section ``Thunder and Lightning'' in @cite{An Introduction to Meteorology}. @end quotation @noindent in a printed manual. Next case: If the node name and the section title are the same in the other manual, you may also leave out the section title. In this case, the node name is used in both instances. For example, @example @@xref@{Electrical Effects,,, weather, An Introduction to Meteorology@}. @end example @noindent produces @example @group *Note (weather)Electrical Effects::. @end group @end example @noindent in Info and @quotation See section ``Electrical Effects'' in @cite{An Introduction to Meteorology}. @end quotation @noindent in a printed manual. In general, there is no reason to have a manual name argument without a printed manual argument, unless no printed manual is generated. You may also want to refer to another manual file that is within a single printed manual---when multiple Texinfo files are incorporated into the same printed manual but can create separate output files in other output formats. In this case, you need to specify only the fourth argument, and not the fifth. If the printed manual title argument is missing, the manual name will be used instead in printed output. A printed manual title argument without an online manual argument is of little use unless only a printed manual is generated from the Texinfo source. The result in online formats depends on the format, and can be, for example, an empty manual name or a reference to the printed manual formatted in a similar way to the printed output. Finally, it's also allowed to leave out all the arguments @emph{except} the fourth and fifth, to refer to another manual as a whole. See the next section. @lowersections @node Referring to a Manual as a Whole @nodedescription Refer to an entire manual. @section Referring to a Manual as a Whole @cindex Manual, referring to as a whole @cindex Referring to an entire manual @anchor{Top Node Naming} @c old name Ordinarily, you must always name a node in a cross-reference. However, it's not unusual to want to refer to another manual as a whole, rather than a particular section within it. In this case, giving any section name is an unnecessary distraction. So, with cross-references to other manuals (@pxref{Four and Five Arguments}), if the first argument is either @samp{Top} (capitalized just that way) or omitted entirely, and the third argument is omitted, the printed output includes no node or section name. (The Info output includes @samp{Top} if it was given.) For example, @example @@xref@{Top,,, make, The GNU Make Manual@}. @end example @noindent produces @example @group *Note (make)Top::. @end group @end example @noindent and @quotation See @cite{The GNU Make Manual}. @end quotation @noindent Info readers will go to the Top node of the manual whether or not the `Top' node is explicitly specified. It's also possible (and is historical practice) to refer to a whole manual by specifying the `Top' node and an appropriate entry for the third argument to the @code{@@xref} command. Using this idiom, to make a cross-reference to @cite{The GNU Make Manual}, you would write: @example @@xref@{Top,, Overview, make, The GNU Make Manual@}. @end example @noindent which produces @example *Note Overview: (make)Top. @end example @noindent in Info and @quotation See section ``Overview'' in @cite{The GNU Make Manual}. @end quotation @noindent in a printed manual. In this example, @samp{Top} is the name of the first node, and @samp{Overview} is the name of the first section of the manual. There is no widely-used convention for naming the first section in a printed manual, this is just what the Make manual happens to use. This arbitrariness of the first name is a principal reason why omitting the third argument in whole-manual cross-references is preferable. @node @code{@@xref} @nodedescription Begin a reference with `See' @dots{} @section @code{@@xref} @anchor{xref}@c old name @findex xref @cindex Cross-references using @code{@@xref} @cindex References using @code{@@xref} The @code{@@xref} command generates a cross-reference for the beginning of a sentence. Examples of using @code{@@xref} are in previous sections. @node @code{@@ref} @nodedescription A reference for the last part of a sentence. @section @code{@@ref} @anchor{ref}@c old name @findex ref @cindex Cross-references using @code{@@ref} @cindex References using @code{@@ref} @code{@@ref} is nearly the same as @code{@@xref} except that it does not generate a `See' in the output, just the reference itself. This makes it useful as the last part of a sentence. @noindent For example, @cindex Hurricanes @example For more information, @@pxref@{This@}, and @@ref@{That@}. @end example @noindent produces in Info: @example For more information, *note This::, and *note That::. @end example @noindent and in printed output: @quotation For more information, see Section 1.1 [This], page 1, and Section 1.2 [That], page 2. @end quotation The @code{@@ref} command can tempt writers to express themselves in a manner that is suitable for a printed manual but looks awkward in the Info format. Bear in mind that your audience could be using both the printed and other output formats such as Info. For example: @cindex Sea surges @example Sea surges are described in @@ref@{Hurricanes@}. @end example @noindent looks ok in the printed output: @quotation Sea surges are described in Section 6.7 [Hurricanes], page 72. @end quotation @noindent but is awkward to read in Info, ``note'' being a verb: @example Sea surges are described in *note Hurricanes::. @end example @node @code{@@pxref} @nodedescription How to write a parenthetical cross-reference. @section @code{@@pxref} @anchor{pxref}@c old name @findex pxref @cindex Cross-references using @code{@@pxref} @cindex References using @code{@@pxref} The parenthetical reference command, @code{@@pxref}, is nearly the same as @code{@@xref}, but it is best used within parentheses. The command differs from @code{@@xref} in that the reference is typeset with a lowercase `see' rather than an uppercase `See'. In Info, @samp{*note} is output. @noindent With one argument, a parenthetical cross-reference looks like this: @cindex Flooding @example @dots{} storms cause flooding (@@pxref@{Hurricanes@}) @dots{} @end example @need 800 @noindent which produces @example @group @dots{} storms cause flooding (*note Hurricanes::) @dots{} @end group @end example @noindent in Info and @quotation @dots{} storms cause flooding (see Section 6.7 [Hurricanes], page 72) @dots{} @end quotation @noindent in a printed manual. In past versions of Texinfo, it was not allowed to write punctuation after a @code{@@pxref}, so it could be used @emph{only} before a right parenthesis. This is no longer the case. The effect of @samp{@@pxref@{@var{node-name}@}} is similar to that of @samp{see @@ref@{@var{node-name}@}}. However, in many circumstances the latter is preferable, as this makes it clear in the Info output that the word ``see'' should be present. @node @code{@@anchor} @nodedescription Defining arbitrary cross-reference targets @section @code{@@anchor}: Defining Arbitrary Cross-reference Targets @anchor{anchor}@c old name @findex anchor @cindex Anchors @cindex Cross-reference targets, arbitrary @cindex Targets for cross-references, arbitrary An @dfn{anchor} is a position in your document, labelled so that cross-references can refer to it, just as they can to nodes. You create an anchor with the @code{@@anchor} command, and give the label as a normal brace-delimited argument. For example: @example This marks the @@anchor@{x-spot@}spot. @dots{} @@xref@{x-spot,,the spot@}. @end example @noindent produces: @example This marks the spot. @dots{} See [the spot], page 1. @end example As you can see, the @code{@@anchor} command itself produces no output. This example defines an anchor `x-spot' just before the word `spot'. You can refer to it later with an @code{@@xref} or other cross reference command, as shown (@pxref{Cross References}). It is best to put @code{@@anchor} commands just before the position you wish to refer to; that way, the reader's eye is led on to the correct text when they jump to the anchor. You can put the @code{@@anchor} command on a line by itself if that helps readability of the source. Whitespace (including newlines) is ignored after @code{@@anchor}. Anchor names, node names and float labels may not conflict. Anchors, nodes and float labels are given similar treatment in some ways; for example, the @code{goto-node} command takes either an anchor name or a node name as an argument. (@xref{Go to node,,, info, Info}.). Anchors names and float labels could also appear in menus (@pxref{Menus}) and node direction pointers (@pxref{Writing a Node}), although this is not recommended. Anchor names share the same constraints as nodes on the characters that can be included (@pxref{Info Node Names Constraints}). @cindex Nodes, deleting or renaming Because of this duality, when you delete or rename a node, it is usually a good idea to define an @code{@@anchor} with the old name. That way, any links to the old node, whether from other Texinfo manuals or general web pages, keep working. @node @code{@@link} @nodedescription How to make a plain link. @section @code{@@link}: Plain, unadorned hyperlink @findex link @cindex Cross-references using @code{@@link} @cindex Plain link @cindex Plain hyperlink @code{@@link} produces a plain hyperlink in output formats that support it, including in HTML, DocBook, @LaTeX{} and online PDF@. The template is: @example @@link@{@var{node-name}, @var{label}, @var{manual-name}@} @end example @var{node-name} is the name of the target node or anchor. Either or both of @var{label} and @var{manual-name} can be omitted. @var{label}, if given, is the text to use for the link. @var{manual-name} is the name of the external manual that the target appears within; if not given, the reference is to the current manual. @code{@@link} has similar output to @code{@@ref}, except that it does produce any extra text around the link label in Info or printed output that would mark it as a cross-reference. Be careful about using @code{@@link} to produce links that are necessary for a user to move around a manual, as these links will do nothing in these output formats. @code{@@link} is best used to add convenience links that are nonetheless not essential for a reader to understand the text of the manual. For example, you might use @code{@@link} in a code sample to reference documentation of a symbol in a programming library. @node @code{@@inforef} @nodedescription How to refer to an Info-only file. @section @code{@@inforef}: Cross-references to Info-only Material @anchor{inforef}@c old name @findex inforef @cindex Cross-references using @code{@@inforef} @cindex References using @code{@@inforef} @code{@@inforef} is used for making cross-references to Info documents---even from a printed manual. This was originally used for Info files that were not generated from any Texinfo source. The command is now obsolete and should not be used. In addition to having little use, similar output can be obtained with @code{@@xref}, @code{@@ref} or @code{@@pxref} with the Info file name as the fourth argument and no fifth argument. The command takes either two or three arguments, in the following order: @enumerate @item The node name. @item The cross-reference name (optional). @item The Info file name. @end enumerate @noindent The template is: @example @@inforef@{@var{node-name}, @var{cross-reference-name}, @var{info-file-name}@} @end example @node @code{@@url} @nodedescription How to refer to a uniform resource locator. @section @code{@@url}, @code{@@uref@{@var{url}[, @var{text}][, @var{replacement}]@}} @anchor{uref}@c old name @anchor{url} @cindex URL @subentry referring to @findex url @cindex @code{href}, producing HTML @code{@@url} produces a reference to a uniform resource locator (URL@:). It takes one mandatory argument, the URL@:, and two optional arguments which control the text that is displayed. In HTML and PDF output, @code{@@url} produces a link you can follow. (To merely indicate a URL without creating a link people can follow, use @code{@@indicateurl}, @pxref{@code{@@indicateurl}}.) @findex uref @code{@@uref} is a synonym for @code{@@url}. (Originally, @code{@@url} had the meaning of @code{@@indicateurl} and @code{@@uref} was required to produce a working link, but in practice @code{@@url} was almost always misused. So we've changed the meaning.) The second argument, if specified, is the text to display (the default is the URL itself); in output formats other than HTML, the URL is output in addition to this text. @cindex Man page, reference to The third argument, if specified, is the text to display, but in this case the URL is not output in any format. This is useful when the text is already sufficiently referential, as in a man page. Also, if the third argument is given, the second argument is ignored. @node @code{@@url} Examples @nodedescription Examples of using all the forms of @code{@@url}. @subsection @code{@@url} Examples @cindex @code{@@url}, examples of using @cindex URL @subentry examples of displaying First, here is an example of the simplest form of @code{@@url}, with just one argument. The given URL is both the target and the visible text of the link: @example The official GNU ftp site is @@url@{http://ftp.gnu.org/gnu@}. @end example @noindent produces: @display The official GNU ftp site is @url{http://ftp.gnu.org/gnu}. @end display @subsubheading Two-argument form of @code{@@url} Here is an example of the two-argument form: @example The official @@url@{http://ftp.gnu.org/gnu, GNU ftp site@} holds programs and texts. @end example @noindent which produces: @display The official @url{http://ftp.gnu.org/gnu, GNU ftp site} holds programs and texts. @end display @noindent The HTML output is this: @example The official <a href="http://ftp.gnu.org/gnu">GNU ftp site</a> holds programs and texts. @end example @noindent In other formats, the output is like this: @example The official GNU ftp site (http://ftp.gnu.org/gnu) holds programs and texts. @end example @subsubheading Three-argument form of @code{@@url} Finally, an example of the three-argument form: @example The @@url@{/man.cgi/1/ls,,ls@} program @dots{} @end example @noindent which, except for HTML, produces: @display The @url{/man.cgi/1/ls,,ls} program @dots{} @end display @noindent but with HTML: @example The <a href="/man.cgi/1/ls">ls</a> program @dots{} @end example By the way, some people prefer to display URLs in the unambiguous format: @display <URL:http://@var{host}/@var{path}> @end display @noindent @cindex @code{<URL...>} convention, not used You can use this form in the input file if you wish. We feel it's not necessary to include the @samp{<URL:} and @samp{>} in the output, since to be useful any software that tries to detect URLs in text already has to detect them without the @samp{<URL:}. @node URL Line Breaking @nodedescription How lines are broken within @code{@@url} text. @subsection URL Line Breaking @cindex Line breaks @subentry URLs @cindex Breakpoints within URLs @TeX{} allows line breaking within URLs at only a few characters (which are special in URLs): @samp{&}, @samp{.}, @samp{#}, @samp{?}, and @samp{/} (but not between two @samp{/} characters). A tiny amount of stretchable space is also inserted around these characters to help with line breaking. For HTML output, modern browsers will also do line breaking within displayed URLs. If you need to allow breaks at other characters you can insert @code{@@/} as needed (@pxref{Line Breaks}). @findex urefbreakstyle By default, in @TeX{} any such breaks at special characters will occur after the character. Some people prefer such breaks to happen before the special character. This can be controlled with the @code{@@urefbreakstyle} command (this command has effect only in @TeX{}): @example @@urefbreakstyle @var{how} @end example @noindent where the argument @var{how} is one of these words: @vindex after@r{, value for @code{@@urefbreakstyle}} @vindex before@r{, value for @code{@@urefbreakstyle}} @vindex none@r{, value for @code{@@urefbreakstyle}} @table @samp @item after (the default) Potentially break after the special characters. @item before Potentially break before the special characters. @item none Do not consider breaking at the special characters at all; any potential breaks must be manually inserted. @end table @node @code{@@url} PDF Output Format @nodedescription A special option to hide links in PDF output. @subsection @code{@@url} PDF Output Format @cindex PDF output of URLs @cindex URLs, PDF output of If the ultimate purpose of a PDF is only to be viewed online, perhaps similar to HTML in some inchoate way, you may not want the URLs to be included in the visible text (just as URLs are not visible to readers of web pages). Texinfo provides a PDF-specific option for this, which must be used inside @code{@@tex}: @findex \urefurlonlylinktrue @example @@tex \global\urefurlonlylinktrue @@end tex @end example The result is that @code{@@url@{http://www.gnu.org, GNU@}} has the visible output of just `GNU', with a link target of @url{http://www.gnu.org}. Ordinarily, the visible output would include both the label and the url: `GNU (@url{http://www.gnu.org})'. This option only has effect when the PDF output is produced with the pdf@TeX{} program, not with other ways of getting from Texinfo to PDF (e.g., @TeX{} to DVI to PDF)@. Consequently, it is ok to specify this option unconditionally within @code{@@tex}, as shown above. It is ignored when DVI is being produced. @node @code{@@cite} @nodedescription How to refer to books not in the Info system. @section @code{@@cite}@{@var{reference}@} @anchor{cite}@c old name @findex cite Use the @code{@@cite} command for the name of a book that lacks a companion Info file. For example, we could refer to @cite{A Book}. The command selects a slanted font in the printed manual, and generates quotation marks in the Info file. If a book is written in Texinfo, it is better to use a cross-reference command since a reader can easily follow such a reference in Info. @xref{@code{@@xref}}. @node PDF Colors @nodedescription Colorizing URLs and other links in PDF output. @section PDF Colors @cindex Colored links, in PDF output @cindex Links, coloring in PDF output @cindex URLs, coloring in PDF output By default, URLs and cross-reference links are printed in black in PDF output. Very occasionally, however, you may want to highlight such ``live'' links with a different color, as is commonly done on web pages. Texinfo provides a PDF-specific option for specifying these colors, which must be used inside @code{@@tex}: @findex \linkcolor @findex \urlcolor @example @@tex \global\def\linkcolor@{1 0 0@} % red \global\def\urlcolor@{0 1 0@} % green @@end tex @end example @code{\urlcolor} changes the color of @code{@@url} output (both the actual URL and any textual label), while @code{\linkcolor} changes the color for cross-references to nodes, etc. They are independent. @cindex RGB color specification. The three given values must be numbers between 0 and 1, specifying the amount of red, green, and blue respectively. These definitions only have an effect when the PDF output is produced with the pdf@TeX{} program, not with other ways of getting from Texinfo to PDF (e.g., @TeX{} to DVI to PDF)@. Consequently, it is ok to specify this option unconditionally within @code{@@tex}, as shown above. It is ignored when DVI is being produced. We do not recommend colorizing just for fun; unless you have a specific reason to use colors, best to skip it. @node Marking Text @nodedescriptionblock Marking words and phrases as code, keyboard input, meta-syntactic variables, and the like. @end nodedescriptionblock @chapter Marking Text, Words and Phrases @cindex Paragraph, marking text within @cindex Marking words and phrases @cindex Words and phrases, marking them @cindex Marking text within a paragraph @cindex Text, marking up In Texinfo, you can mark words and phrases in a variety of ways. The Texinfo processors use this information to determine how to highlight the text. You can specify, for example, whether a word or phrase is a defining occurrence, a metasyntactic variable, or a symbol used in a program. Also, you can emphasize text, in several different ways. @node Indicating @nodedescription How to indicate definitions, files, etc. @section Indicating Definitions, Commands, etc. @cindex Highlighting text @cindex Indicating commands, definitions, etc. Texinfo has commands for indicating just what kind of object a piece of text refers to. For example, email addresses are marked by @code{@@email}; that way, the result can be a live link to send email when the output format supports it. If the email address was simply marked as ``print in a typewriter font'', that would not be possible. @node Useful Highlighting @nodedescription Highlighting provides useful information. @subsection Highlighting Commands are Useful The commands serve a variety of purposes: @table @code @item @@code@{@var{sample-code}@} Indicate text that is a literal example of a piece of a program. @xref{@code{@@code}}. @item @@kbd@{@var{keyboard-characters}@} Indicate keyboard input. @xref{@code{@@kbd}}. @item @@key@{@var{key-name}@} Indicate the conventional name for a key on a keyboard. @xref{@code{@@key}}. @item @@samp@{@var{text}@} Indicate text that is a literal example of a sequence of characters. @xref{@code{@@samp}}. @item @@verb@{@var{text}@} Write a verbatim sequence of characters. @xref{@code{@@verb}}. @item @@var@{@var{metasyntactic-variable}@} Indicate a metasyntactic variable. @xref{@code{@@var}}. @item @@env@{@var{environment-variable}@} Indicate an environment variable. @xref{@code{@@env}}. @item @@file@{@var{file-name}@} Indicate the name of a file. @xref{@code{@@file}}. @item @@command@{@var{command-name}@} Indicate the name of a command. @xref{@code{@@command}}. @item @@option@{@var{option}@} Indicate a command-line option. @xref{@code{@@option}}. @item @@dfn@{@var{term}@} Indicate the introductory or defining use of a term. @xref{@code{@@dfn}}. @item @@cite@{@var{reference}@} Indicate the name of a book. @xref{@code{@@cite}}. @item @@abbr@{@var{abbreviation}@} Indicate an abbreviation, such as `Comput.'. @item @@acronym@{@var{acronym}@} Indicate an acronym. @xref{@code{@@acronym}}. @item @@indicateurl@{@var{uniform-resource-locator}@} Indicate an example (that is, nonfunctional) uniform resource locator. @xref{@code{@@indicateurl}}. (Use @code{@@url} (@pxref{@code{@@url}}) for live URLs.) @item @@email@{@var{email-address}[, @var{displayed-text}]@} Indicate an electronic mail address. @xref{@code{@@email}}. @end table @node @code{@@code} @nodedescription Indicating program code. @subsection @code{@@code}@{@var{sample-code}@} @anchor{code}@c old name @findex code @cindex Syntactic tokens, indicating Use the @code{@@code} command to indicate text that is a piece of a program and which consists of entire syntactic tokens. Enclose the text in braces. @cindex Expressions in a program, indicating @cindex Keywords, indicating @cindex Reserved words, indicating Thus, you should use @code{@@code} for an expression in a program, for the name of a variable or function used in a program, or for a keyword in a programming language. Use @code{@@code} for command names in languages that resemble programming languages, such as Texinfo. For example, @code{@@code} and @code{@@samp} are produced by writing @samp{@@code@{@@@@code@}} and @samp{@@code@{@@@@samp@}} in the Texinfo source, respectively. @cindex Case, not altering in @code{@@code} It is incorrect to alter the case of a word inside a @code{@@code} command when it appears at the beginning of a sentence. Most computer languages are case sensitive. In C, for example, @code{Printf} is different from the identifier @code{printf}, and most likely is a misspelling of it. Even in languages which are not case sensitive, it is confusing to a human reader to see identifiers spelled in different ways. Pick one spelling and always use that. If you do not want to start a sentence with a command name written all in lowercase, you should rearrange the sentence. The @code{@@code} argument is typeset in a typewriter (monospace) font. where the output format allows this. For example, @example The function returns @@code@{nil@}. @end example @noindent produces this: @quotation The function returns @code{nil}. @end quotation Here are some cases for which it is preferable @emph{not} to use @code{@@code}: @itemize @bullet @item For shell command names, such as @command{ls} (use @code{@@command}). @item For environment variables, such as @env{TEXINPUTS} (use @code{@@env}). @item For shell options, such as @samp{-c}, when such options stand alone (use @code{@@option}). @item An entire shell command often looks better if written using @code{@@samp} rather than @code{@@code}. In this case, the rule is to choose the more pleasing format. @item For a string of characters shorter than a syntactic token. For example, if you are writing about @samp{goto-ch}, which is just a part of the name for the @code{goto-char} Emacs Lisp function, you should use @code{@@samp}. @item In general, when writing about the characters used in a token; for example, do not use @code{@@code} when you are explaining what letters or printable symbols can be used in the names of functions. (Use @code{@@samp}.) Also, you should not use @code{@@code} to mark text that is considered input to programs unless the input is written in a language that is like a programming language. For example, you should not use @code{@@code} for the keystroke commands of GNU Emacs (use @code{@@kbd} instead) although you may use @code{@@code} for the names of the Emacs Lisp functions that the keystroke commands invoke. @end itemize By default, @TeX{} will consider breaking lines at @samp{-} and @samp{_} characters within @code{@@code} and related commands. This can be controlled with @code{@@allowcodebreaks} (@pxref{@code{@@allowcodebreaks}}). In the HTML output breaking lines is up to the browser's behavior. For Info, it seems better never to make such breaks. For Info and plaintext, quotation characters are usually output around the output of the @code{@@code} command and related commands (e.g., @code{@@kbd}, @code{@@command}) except in typewriter-like contexts such as the @code{@@example} environment (@pxref{@code{@@example}}) and @code{@@code} itself, etc. To control which quoting characters are inserted by @command{texi2any} in the output of @samp{@@code}, etc., see the @code{OPEN_QUOTE_SYMBOL} and @code{CLOSE_QUOTE_SYMBOL} customization variables (@pxref{Other Customization Variables}). @node @code{@@kbd} @nodedescription Showing keyboard input. @subsection @code{@@kbd}@{@var{keyboard-characters}@} @anchor{kbd}@c old name @findex kbd @cindex Keyboard input Use the @code{@@kbd} command for characters of input to be typed by users. For example, to refer to the characters @kbd{M-a}, write: @example @@kbd@{M-a@} @end example @noindent and to refer to the characters @kbd{M-x shell}, write: @example @@kbd@{M-x shell@} @end example @cindex User input @cindex Slanted typewriter font, for @code{@@kbd} By default, the @code{@@kbd} command produces a different font (slanted typewriter instead of normal typewriter, where the output format allows), so users can distinguish the characters that they are supposed to type from those that the computer outputs. @findex kbdinputstyle Since the usage of @code{@@kbd} varies from manual to manual, you can control the font switching with the @code{@@kbdinputstyle} command. This command has no effect on Info output. Write this command at the beginning of a line with a single word as an argument, one of the following: @vindex distinct@r{, value for @code{@@kbdinputstyle}} @vindex example@r{, value for @code{@@kbdinputstyle}} @vindex code@r{, value for @code{@@kbdinputstyle}} @table @samp @item code Always use the same font for @code{@@kbd} as @code{@@code}. @item example Use the distinguishing font for @code{@@kbd} only in @code{@@example} and similar environments. @item distinct (the default) Always use the distinguishing font for @code{@@kbd}. @end table You can embed another @@-command inside the braces of a @code{@@kbd} command. Here, for example, is the way to describe a command that would be described more verbosely as ``press the @samp{r} key and then press the @key{RETURN} key'': @example @@kbd@{r @@key@{RET@}@} @end example @noindent This produces: @kbd{r @key{RET}}. (The present manual uses the default for @code{@@kbdinputstyle}.) You also use the @code{@@kbd} command if you are spelling out the letters you type; for example: @example To give the @@code@{logout@} command, type the characters @@kbd@{l o g o u t @@key@{RET@}@}. @end example @noindent This produces: @quotation To give the @code{logout} command, type the characters @kbd{l o g o u t @key{RET}}. @end quotation (Also, this example shows that you can add spaces for clarity. If you explicitly want to mention a space character as one of the characters of input, write @kbd{@@key@{SPC@}} for it.) @node @code{@@key} @nodedescription Specifying keys. @subsection @code{@@key}@{@var{key-name}@} @anchor{key}@c old name @findex key Use the @code{@@key} command for the conventional name for a key on a keyboard, as in: @example @@key@{RET@} @end example You can use the @code{@@key} command within the argument of an @code{@@kbd} command when the sequence of characters to be typed includes one or more keys that are described by name. For example, to produce @kbd{C-x @key{ESC}} and @kbd{M-@key{TAB}} you would type: @example @@kbd@{C-x @@key@{ESC@}@} @@kbd@{M-@@key@{TAB@}@} @end example Here is a list of the recommended names for keys: @cindex Recommended names for keys @cindex Keys, recommended names @cindex Names recommended for keys @cindex Abbreviations for keys @cindex Control keys, specifying @cindex Meta keys, specifying @quotation @table @t @item SPC Space @item RET Return @item LFD Linefeed (however, since most keyboards nowadays do not have a Linefeed key, it might be better to call this character @kbd{C-j}) @item TAB Tab @item BS Backspace @item ESC Escape @item DELETE Delete @item SHIFT Shift @item CTRL Control @item META Meta @end table @end quotation @cindex META key There are subtleties to handling words like `meta' or `ctrl' that are names of modifier keys. When mentioning a character in which the modifier key is used, such as @kbd{Meta-a}, use the @code{@@kbd} command alone; do not use the @code{@@key} command; but when you are referring to the modifier key in isolation, use the @code{@@key} command. For example, write @samp{@@kbd@{Meta-a@}} to produce @kbd{Meta-a} and @samp{@@key@{META@}} to produce @key{META}. @node @code{@@samp} @nodedescription Indicating a literal sequence of characters. @subsection @code{@@samp}@{@var{text}@} @anchor{samp}@c old name @findex samp Use the @code{@@samp} command to indicate text that is a literal example or `sample' of a sequence of characters in a file, string, pattern, etc. Enclose the text in braces. The argument appears within single quotation marks; in addition, it is printed in a fixed-width font. @example To match @@samp@{foo@} at the end of the line, use the regexp @@samp@{foo$@}. @end example @noindent produces @quotation To match @samp{foo} at the end of the line, use the regexp @samp{foo$}. @end quotation Any time you are referring to single characters, you should use @code{@@samp} unless @code{@@kbd} or @code{@@key} is more appropriate. Also, you may use @code{@@samp} for entire statements in C and for entire shell commands---in this case, @code{@@samp} often looks better than @code{@@code}. Basically, @code{@@samp} is a catchall for whatever is not covered by @code{@@code}, @code{@@kbd}, @code{@@key}, @code{@@command}, etc. Only include punctuation marks within braces if they are part of the string you are specifying. Write punctuation marks outside the braces if those punctuation marks are part of the English text that surrounds the string. In the following sentence, for example, the commas and period are outside of the braces: @example @group In English, the vowels are @@samp@{a@}, @@samp@{e@}, @@samp@{i@}, @@samp@{o@}, @@samp@{u@}, and sometimes @@samp@{y@}. @end group @end example @noindent This produces: @quotation In English, the vowels are @samp{a}, @samp{e}, @samp{i}, @samp{o}, @samp{u}, and sometimes @samp{y}. @end quotation @node @code{@@verb} @nodedescription Indicating a verbatim sequence of characters. @subsection @code{@@verb}@{@var{char}@var{text}@var{char}@} @anchor{verb}@c old name @findex verb @cindex Verbatim in-line text @cindex Delimiter character, for verbatim Use the @code{@@verb} command to print a verbatim sequence of characters. Like @LaTeX{}'s @code{\verb} command, the verbatim text can be quoted using any unique delimiter character. Enclose the verbatim text, including the delimiters, in braces. Text is printed in a fixed-width font: @example How many @@verb@{|@@|@}-escapes does one need to print this @@verb@{.@@a @@b.@@c.@} string or @@verb@{+@@'e?`@{@}!`\+@} this? @end example @noindent produces @example How many @verb{|@|}-escapes does one need to print this @verb{.@a @b.@c.} string or @verb{+@'e?`{}!`\+} this? @end example This is in contrast to @code{@@samp} (see the previous section), @code{@@code}, and similar commands; in those cases, the argument is normal Texinfo text, where the three characters @code{@@@{@}} are special, as usual. With @code{@@verb}, nothing is special except the delimiter character you choose. The delimiter character itself may appear inside the verbatim text, as shown above. As another example, @samp{@@verb@{...@}} prints a single (fixed-width) period. It is not reliable to use @code{@@verb} inside other Texinfo constructs. In particular, it does not work to use @code{@@verb} in anything related to cross-referencing, such as section titles or figure captions. @node @code{@@var} @nodedescription Indicating metasyntactic variables. @subsection @code{@@var}@{@var{metasyntactic-variable}@} @anchor{var}@c old name @findex var Use the @code{@@var} command to indicate metasyntactic variables. A @dfn{metasyntactic variable} is something that stands for another piece of text. For example, you should use a metasyntactic variable in the documentation of a function to describe the arguments that are passed to that function. Do not use @code{@@var} for the names of normal variables in computer programs. These are specific names, so @code{@@code} is correct for them. For example, the Emacs Lisp variable @code{texinfo-tex-command} is not a metasyntactic variable; it is properly formatted using @code{@@code}. Do not use @code{@@var} for environment variables either; @code{@@env} is correct for them (see the next section). The effect of @code{@@var} in the Info file is to change the case of the argument to all uppercase. In the printed manual, the argument is output in slanted type. @footnote{In @TeX{} output, @code{@@var} currently uses a slanted typewriter font in code contexts such as @code{@@code} or @code{@@example}. We plan to change this in the next release to use a variable-width, slanted roman font in all contexts. To avoid this change, set the @samp{txicodevaristt} flag using @code{@@set}; specify @samp{@@clear txicodevaristt} to make this change now (@pxref{@code{@@set @@value}}). Note that this flag does nothing in @LaTeX{} output.} @need 700 For example, @example To delete file @@var@{filename@}, type @@samp@{rm @@var@{filename@}@}. @end example @noindent produces @quotation To delete file @var{filename}, type @samp{rm @var{filename}}. @end quotation @noindent (Note that @code{@@var} may appear inside @code{@@code}, @code{@@samp}, @code{@@file}, etc.) Write a metasyntactic variable all in lowercase without spaces, and use hyphens to make it more readable. Thus, the Texinfo source for the illustration of how to begin a Texinfo manual looks like this: @example @group \input texinfo @@@@settitle @@var@{name-of-manual@} @end group @end example @noindent This produces: @example @group \input texinfo @@settitle @var{name-of-manual} @end group @end example In some documentation styles, metasyntactic variables are shown with angle brackets, for example: @example @dots{}, type rm <filename> @end example @noindent However, that is not the style that Texinfo uses. @c FIXME add a customization variable? Add an example on how to do that @c for HTML? @c (You can, of course, modify the sources to @file{texinfo.tex} @c and the Info formatting commands @c to output the @code{<@dots{}>} format if you wish.) @node @code{@@env} @nodedescription Indicating environment variables. @subsection @code{@@env}@{@var{environment-variable}@} @anchor{env}@c old name @findex env Use the @code{@@env} command to indicate environment variables, as used by many operating systems, including GNU@. Do not use it for @emph{meta}syntactic variables; use @code{@@var} for those (see the previous section). @code{@@env} is equivalent to @code{@@code} in its effects. For example: @example The @@env@{PATH@} environment variable @dots{} @end example @noindent produces @quotation The @env{PATH} environment variable @dots{} @end quotation @node @code{@@file} @nodedescription Indicating file names. @subsection @code{@@file}@{@var{file-name}@} @anchor{file}@c old name @findex file Use the @code{@@file} command to indicate text that is the name of a file, buffer, or directory, or is the name of a node in Info. You can also use the command for file name suffixes. Do not use @code{@@file} for symbols in a programming language; use @code{@@code}. @code{@@file} is equivalent to @code{code} in its effects. For example, @example The @@file@{.el@} files are in the @@file@{/usr/local/emacs/lisp@} directory. @end example @noindent produces @quotation The @file{.el} files are in the @file{/usr/local/emacs/lisp} directory. @end quotation @node @code{@@command} @nodedescription Indicating command names. @subsection @code{@@command}@{@var{command-name}@} @anchor{command}@c old name @findex command @cindex Command names, indicating @cindex Program names, indicating Use the @code{@@command} command to indicate command names, such as @command{ls} or @command{cc}. @code{@@command} is equivalent to @code{@@code} in its effects. For example: @example The command @@command@{ls@} lists directory contents. @end example @noindent produces @quotation The command @command{ls} lists directory contents. @end quotation You should write the name of a program in the ordinary text font, rather than using @code{@@command}, if you regard it as a new English word, such as `Emacs' or `Bison'. When writing an entire shell command invocation, as in @samp{ls -l}, you should use either @code{@@samp} or @code{@@code} at your discretion. @node @code{@@option} @nodedescription Indicating option names. @subsection @code{@@option}@{@var{option-name}@} @anchor{option}@c old name @findex option Use the @code{@@option} command to indicate a command-line option; for example, @option{-l} or @option{--version} or @option{--output=@var{filename}}. @code{@@option} is equivalent to @code{@@code} in its effects. For example: @example The option @@option@{-l@} produces a long listing. @end example @noindent produces @quotation The option @option{-l} produces a long listing. @end quotation @node @code{@@dfn} @nodedescription Specifying definitions. @subsection @code{@@dfn}@{@var{term}@} @anchor{dfn}@c old name @findex dfn Use the @code{@@dfn} command to identify the introductory or defining use of a technical term. Use the command only in passages whose purpose is to introduce a term which will be used again or which the reader ought to know. Mere passing mention of a term for the first time does not deserve @code{@@dfn}. The command selects a slanted font in the printed manual, and generates double quotation marks in the Info file. For example: @example Getting rid of a file is called @@dfn@{deleting@} it. @end example @noindent produces @quotation Getting rid of a file is called @dfn{deleting} it. @end quotation As a general rule, a sentence containing the defining occurrence of a term should be a definition of the term. The sentence does not need to say explicitly that it is a definition, but it should contain the information of a definition---it should make the meaning clear. @node @code{@@abbr} @nodedescription Indicating abbreviations. @subsection @code{@@abbr}@{@var{abbreviation}[, @var{meaning}]@} @anchor{abbr}@c old name @findex abbr @cindex Abbreviations, tagging You can use the @code{@@abbr} command for general abbreviations. The abbreviation is given as the single argument in braces, as in @samp{@@abbr@{Comput.@}}. As a matter of style, or for particular abbreviations, you may prefer to omit periods, as in @samp{@@abbr@{Mr@} Stallman}. @code{@@abbr} accepts an optional second argument, intended to be used for the meaning of the abbreviation. If the abbreviation ends with a lowercase letter and a period, and is not at the end of a sentence, and has no second argument, remember to use the @code{@@.} command (@pxref{Ending a Sentence}) to get the correct spacing. However, you do not have to use @code{@@.} within the abbreviation itself; Texinfo automatically assumes periods within the abbreviation do not end a sentence. In output formats with an appropriate tag, such as HTML and DocBook, this tag is used. Otherwise, the first argument is printed as-is; if the second argument is present, it is printed in parentheses after the abbreviation. For instance: @example @@abbr@{Comput. J., Computer Journal@} @end example @noindent produces: @display @abbr{Comput. J., Computer Journal} @end display For abbreviations consisting of all capital letters, you may prefer to use the @code{@@acronym} command instead. See the next section for more on the usage of these two commands. @node @code{@@acronym} @nodedescription Indicating acronyms. @subsection @code{@@acronym}@{@var{acronym}[, @var{meaning}]@} @anchor{acronym}@c old name @findex acronym @cindex NASA, as acronym @cindex Acronyms, tagging You can use the @code{@@acronym} command for abbreviations written in all capital letters, such as `@acronym{NASA}'. The abbreviation is given as the single argument in braces, as in @samp{@@acronym@{NASA@}}. As a matter of style, or for particular acronyms, you may prefer to use periods, as in @samp{@@acronym@{N.A.S.A.@}}. @code{@@acronym} accepts an optional second argument, intended to be used for the meaning of the acronym. If the acronym is at the end of a sentence, and if there is no second argument, remember to use the @code{@@.} or similar command (@pxref{Ending a Sentence}) to get the correct spacing. In @TeX{}, the acronym is printed in slightly smaller font. In the Info output, the argument is printed as-is. In either format, and in @LaTeX{} output, if the second argument is present, it is printed in parentheses after the acronym. In HTML and DocBook the appropriate tag is used. For instance (since GNU is a recursive acronym, we use @code{@@acronym} recursively): @example @@acronym@{GNU, @@acronym@{GNU@}'s Not Unix@} @end example @noindent produces: @display @acronym{GNU, @acronym{GNU}'s Not Unix} @end display @cindex Family names, in all capitals In some circumstances, it is conventional to print family names in all capitals. Don't use @code{@@acronym} for this, since a name is not an acronym. Use @code{@@sc} instead (@pxref{Smallcaps}). @code{@@abbr} and @code{@@acronym} are closely related commands: they both signal to the reader that a shortened form is being used, and possibly give a meaning. When choosing whether to use these two commands, please bear the following in mind. @itemize @minus @item In common English usage, acronyms are a subset of abbreviations: they include pronounceable words like `@acronym{NATO}', `radar', and `snafu'; some sources also include syllable acronyms like `Usenet', hybrids like `@acronym{SIGGRAPH}', and unpronounceable initialisms like `@acronym{FBI}'. @item In Texinfo, an acronym (but not an abbreviation) should consist only of capital letters and periods, no lowercase. @item In @TeX{}, an acronym (but not an abbreviation) is printed in a slightly smaller font. @item It usually turns out to be quite difficult and/or time-consuming to consistently use @code{@@acronym} for all sequences of uppercase letters. Furthermore, it looks strange for some acronyms to be in the normal font size and others to be smaller. Thus, a simpler approach you may wish to consider is to avoid @code{@@acronym} and just typeset everything as normal text in all capitals: @samp{GNU}, producing the output `GNU'. @item In general, it's not essential to use either of these commands for all abbreviations; use your judgment. Text is perfectly readable without them. @end itemize @node @code{@@indicateurl} @nodedescription Indicating an example URL. @subsection @code{@@indicateurl}@{@var{uniform-resource-locator}@} @anchor{indicateurl}@c old name @findex indicateurl @cindex URL @subentry indicating Use the @code{@@indicateurl} command to indicate a uniform resource locator on the World Wide Web. This is purely for markup purposes and does not produce a link you can follow (use the @code{@@url} or @code{@@uref} command for that, @pxref{@code{@@url}}). @code{@@indicateurl} is useful for URLs which do not actually exist. For example: @example For example, the URL might be @@indicateurl@{http://example.org/path@}. @end example @noindent which produces: @display For example, the URL might be @indicateurl{http://example.org/path}. @end display The output from @code{@@indicateurl} is usually like that of @code{@@samp} (@pxref{@code{@@samp}}). @node @code{@@email} @nodedescription Indicating an electronic mail address. @subsection @code{@@email}@{@var{email-address}[, @var{displayed-text}]@} @anchor{email}@c old name @findex email Use the @code{@@email} command to indicate an electronic mail address. It takes one mandatory argument, the address, and one optional argument, the text to display (the default is the address itself). @cindex Mailto link In Info, the address is shown in angle brackets, preceded by the text to display if any. In printed output, the angle brackets are omitted. In HTML and DocBook output, @code{@@email} produces a @samp{mailto} link. In HTML, a @samp{mailto} link usually brings up a mail composition window. For example: @example Send bug reports to @@email@{bug-texinfo@@@@gnu.org@}, suggestions to the @@email@{bug-texinfo@@@@gnu.org, same place@}. @end example @noindent produces @display Send bug reports to @email{bug-texinfo@@gnu.org}, suggestions to the @email{bug-texinfo@@gnu.org, same place}. @end display @node Emphasis @nodedescription How to emphasize text. @section Emphasizing Text @cindex Emphasizing text Usually, Texinfo changes the font to mark words in the text according to the category the words belong to; an example is the @code{@@code} command. Most often, this is the best way to mark words. However, sometimes you will want to emphasize text without indicating a category. Texinfo has two commands to do this. Also, Texinfo has several commands that specify the font in which text will be output. These commands have no effect in Info and only one of them, the @code{@@r} command, has any regular use. @node @code{@@emph @@strong} @nodedescription How to emphasize text in Texinfo. @subsection @code{@@emph}@{@var{text}@} and @code{@@strong}@{@var{text}@} @anchor{emph & strong}@c oldname @findex emph @findex strong @cindex Emphasizing text, font for The @code{@@emph} and @code{@@strong} commands are for emphasis; @code{@@strong} is stronger. In printed output, @code{@@emph} produces @emph{italics} and @code{@@strong} produces @strong{bold}. In the Info output, @code{@@emph} surrounds the text with underscores (@samp{_}), and @code{@@strong} puts asterisks around the text. For example, @example @group @@strong@{Caution:@} @@samp@{rm * .[^.]*@} removes @@emph@{all@} files in the directory. @end group @end example @noindent produces the following: @quotation @strong{Caution}: @samp{rm * .[^.]*} removes @emph{all} files in the directory. @end quotation The @code{@@strong} command is seldom used except to mark what is, in effect, a typographical element, such as the word `Caution' in the preceding example. @quotation Caution Do not use @code{@@strong} with the word @samp{Note} followed by a space; Info will mistake the combination for a cross-reference. Use a phrase such as @strong{Please notice} or @strong{Caution} instead, or the optional argument to @code{@@quotation}---@samp{Note} is allowable there. @end quotation @node Smallcaps @nodedescription How to use the small caps font. @subsection @code{@@sc}@{@var{text}@}: The Small Caps Font @cindex Small caps font @findex sc Use the @samp{@@sc} command to set text in @sc{a small caps font} (where possible). Write the text you want to be in small caps between braces in lowercase, like this: @example Richard @@sc@{Stallman@} a commenc@'{e} le projet GNU. @end example @noindent This produces: @display Richard @sc{Stallman} a commenc@'{e} le projet GNU. @end display As shown here, we recommend reserving @code{@@sc} for special cases where you want typographic small caps; family names are one such, especially in languages other than English, though there are no hard-and-fast rules about such things. @cindex @code{<small>} tag @TeX{} typesets any uppercase letters between the braces of an @code{@@sc} command in full-size capitals; only lowercase letters are printed in the small caps font. In the Info output, the argument to @code{@@sc} is printed in all uppercase. In HTML, the argument is uppercased and the output marked with the @code{<small>} tag to reduce the font size, since HTML cannot easily represent true small caps. In @LaTeX{}, a command setting small caps fonts is output. Overall, we recommend using standard upper- and lowercase letters wherever possible. @node Fonts @nodedescription Various font commands for printed output. @subsection Fonts for Printing @cindex Fonts for printing @findex fonttextsize @cindex Font size, reducing @cindex Reducing font size @cindex Smaller fonts Texinfo provides one command to change the size of the main body font in printed output for a document: @code{@@fonttextsize}. It has no effect in other output. It takes a single argument on the remainder of the line, which must be either @samp{10} or @samp{11}. For example: @example @@fonttextsize 10 @end example @cindex Printing cost, reducing The effect is to reduce the body font to a 10@dmn{pt} size (the default is 11@dmn{pt}). Fonts for other elements, such as sections and chapters, are reduced accordingly. This should only be used in conjunction with @code{@@smallbook} (@pxref{@code{@@smallbook}}) or similar, since 10@dmn{pt} fonts on standard paper (8.5x11 or A4) are too small. One reason to use this command is to save pages, and hence printing cost, for physical books. Texinfo does not at present have commands to switch the font family to use, or more general size-changing commands. Texinfo also provides a number of font commands that specify font changes in the printed manual and (where possible) in the HTML and DocBook output. They have no effect in Info. All the commands apply to a following argument surrounded by braces. @table @code @findex b @r{(bold font)} @ifset commandlookup @findex b @end ifset @cindex Bold font @item @@b selects @b{bold} face; @findex i @r{(italic font)} @ifset commandlookup @findex i @end ifset @cindex Italic font @item @@i selects an @i{italic} font; @findex r @r{(roman font)} @ifset commandlookup @findex r @end ifset @cindex Roman font @cindex Default font @item @@r selects a @r{roman} font, which is the usual font in which text is printed. It may or may not be seriffed. @findex sansserif @cindex Sans serif font @item @@sansserif selects a @sansserif{sans serif} font; @findex slanted @cindex Slanted font @cindex Oblique font @item @@slanted selects a @slanted{slanted} font; @findex t @r{(typewriter font)} @ifset commandlookup @findex t @end ifset @cindex Monospace font @cindex Fixed-width font @cindex Typewriter font @item @@t selects the @t{fixed-width}, typewriter-style font used by @code{@@code}; @end table @ignore (The commands with longer names were invented much later than the others, at which time it did not seem desirable to use very short names for such infrequently needed features.) @end ignore The @code{@@r} command can be useful in example-like environments, to write comments in the standard roman font instead of the fixed-width font. This looks better in printed output. For example, @example @group @@lisp (+ 2 2) ; @@r@{Add two plus two.@} @@end lisp @end group @end example @noindent produces @lisp (+ 2 2) ; @r{Add two plus two.} @end lisp The @code{@@t} command can occasionally be useful for producing output in a typewriter font where that is supported, but no distinction with quotation marks is needed in Info or plain text. (Compare @code{@@t@{foo@}} producing @t{foo} with @code{@@code@{foo@}} producing @code{foo}.) Here are some possible reasons for using @code{@@t} instead of @code{@@code}: @itemize @minus @item The argument is a single character @item There are already quotes of some kind enclosing the argument @item It's evident from context or the argument itself that the argument could be computer code (e.g.@: name of a Usenet newsgroup) @end itemize In general, the other font commands are unlikely to be useful; they exist primarily to make it possible to document the functionality of specific font effects, such as in @TeX{} and related packages. @node Quotations and Examples @nodedescription Block quotations, examples, etc. @chapter Quotations and Examples Quotations and examples are blocks of text consisting of one or more whole paragraphs that are set off from the bulk of the text and treated differently. They are usually indented in the output. In Texinfo, you always begin a quotation or example by writing an @@-command at the beginning of a line by itself, and end it by writing an @code{@@end} command that is also at the beginning of a line by itself. For instance, you begin an example by writing @code{@@example} by itself at the beginning of a line and end the example by writing @code{@@end example} on a line by itself, at the beginning of that line, and with only one space between the @code{@@end} and the @code{example}. @node Block Enclosing Commands @nodedescription Different constructs for different purposes. @section Block Enclosing Commands Here is a summary of commands that enclose blocks of text, also known as @dfn{environments}. They're explained further in the following sections. @table @code @item @@quotation Indicate text that is quoted. The text is filled, indented (from both margins), and printed in a roman font by default. @item @@indentedblock Like @code{@@quotation}, but the text is indented only on the left. @item @@example Illustrate code, commands, and the like. The text is printed in a fixed-width font, and indented but not filled. @item @@lisp Like @code{@@example}, but specifically for illustrating Lisp code. The text is printed in a fixed-width font, and indented but not filled. @item @@verbatim Mark a piece of text that is to be printed verbatim; no character substitutions are made and all commands are ignored, until the next @code{@@end verbatim}. The text is printed in a fixed-width font, and not indented or filled. Extra spaces and blank lines are significant, and tabs are expanded. @item @@display Display illustrative text. The text is indented but not filled, and no font is selected (so, by default, the font is roman). @item @@format Like @code{@@display} (the text is not filled and no font is selected), but the text is not indented. @item @@smallquotation @itemx @@smallindentedblock @itemx @@smallexample @itemx @@smalllisp @itemx @@smalldisplay @itemx @@smallformat These @code{@@small...} commands are just like their non-small counterparts, except that they output text in a smaller font size, where possible. @item @@flushleft @itemx @@flushright Text is not filled, but is set flush with the left or right margin, respectively. @item @@raggedright Text is filled, but only justified on the left, leaving the right margin ragged. @item @@cartouche Highlight text, often an example or quotation, by drawing a box with rounded corners around it. @end table The @code{@@exdent} command is used within the above constructs to undo the indentation of a line. The @code{@@noindent} command may be used after one of the above constructs (or at the beginning of any paragraph) to prevent the following text from being indented as a new paragraph. @node @code{@@quotation} @nodedescription Writing a quotation. @section @code{@@quotation}: Block Quotations @anchor{quotation}@c old name @cindex Quotations @findex quotation The text of a quotation is processed like normal text (regular font, text is filled) except that: @itemize @bullet @item the left margin is closer to the center of the page, so the whole of the quotation is indented; the right margin may also be closer to the center of the page @item the first lines of paragraphs are indented no more than other lines; and @item an @code{@@author} command may be given to specify the author of the quotation. @end itemize @quotation This is an example of text written between a @code{@@quotation} command and an @code{@@end quotation} command. A @code{@@quotation} command is most often used to indicate text that is excerpted from another (real or hypothetical) printed work. @end quotation Write a @code{@@quotation} command as text on a line by itself. This line will disappear from the output. Mark the end of the quotation with a line beginning with and containing only @code{@@end quotation}. The @code{@@end quotation} line will likewise disappear from the output. @code{@@quotation} takes one optional argument, given on the remainder of the line. This text, if present, is included at the beginning of the quotation in bold or otherwise emphasized, and followed with a @samp{:}. For example: @example @@quotation Note This is a foo. @@end quotation @end example @noindent produces @quotation Note This is a foo. @end quotation If the @code{@@quotation} argument is one of these English words (case-insensitive): @example Caution Important Note Tip Warning @end example @cindex @code{<caution>} DocBook tag @cindex @code{<important>} DocBook tag @cindex @code{<note>} DocBook tag @cindex @code{<tip>} DocBook tag @cindex @code{<warning>} DocBook tag @cindex @code{<blockquote>} DocBook tag @noindent then the DocBook output uses corresponding special tags (@code{<note>}, etc.)@: instead of the default @code{<blockquote>}. If the author of the quotation is specified in the @code{@@quotation} block with the @code{@@author} command, a line with the author name is displayed after the quotation: @example @@quotation People sometimes ask me if it is a sin in the Church of Emacs to use vi. Using a free version of vi is not a sin; it is a penance. So happy hacking. @@author Richard Stallman @@end quotation @end example @noindent produces @quotation People sometimes ask me if it is a sin in the Church of Emacs to use vi. Using a free version of vi is not a sin; it is a penance. So happy hacking. @author Richard Stallman @end quotation @node @code{@@indentedblock} @nodedescription Block of text indented on left. @section @code{@@indentedblock}: Indented text blocks @cindex Indented text block @findex indentedblock The @code{@@indentedblock} environment is similar to @code{@@quotation}, except that text is only indented on the left (and there is no optional argument for an author). Thus, the text font remains unchanged, and text is gathered and filled as usual, but the left margin is increased. For example: @indentedblock This is an example of text written between an @code{@@indentedblock} command and an @code{@@end indentedblock} command. The @code{@@indentedblock} environment can contain any text or other commands desired. @end indentedblock This is written in the Texinfo source as: @example @@indentedblock This is an example ... @@end indentedblock @end example @node @code{@@example} @nodedescription Writing an example in a fixed-width font. @section @code{@@example}: Example Text @anchor{example}@c old name @findex example @cindex Examples, formatting them @cindex Formatting examples The @code{@@example} environment is used to indicate computer input or output that is not part of the running text. If you want to embed code fragments within sentences, use the @code{@@code} command or its relatives instead (@pxref{@code{@@code}}). Write an @code{@@example} command at the beginning of a line by itself. Mark the end of the block with @code{@@end example}. For example, @example @@example cp foo @@var@{dest1@}; \ cp foo @@var@{dest2@} @@end example @end example @noindent produces @example cp foo @var{dest1}; \ cp foo @var{dest2} @end example The output uses a fixed-width font and is indented. Each line in the input file is a line in the output; that is, the source text is not filled. Extra spaces and blank lines are significant. Texinfo commands @emph{are} expanded; if you want the output to be the input verbatim, use the @code{@@verbatim} environment instead (@pxref{@code{@@verbatim}}). Examples are often, logically speaking, ``in the middle'' of a paragraph, and the text that continues afterwards should not be indented, as in the example above. The @code{@@noindent} command prevents a piece of text from being indented as if it were a new paragraph (@pxref{@code{@@noindent}}). If you wish to use the normal roman font for a code comment, you can use the @code{@@r} command (@pxref{Fonts}). You may optionally give arguments to the @code{@@example} command, separated by commas if there is more than one. In the HTML output, any such arguments are output as class names, prefixed by the string @samp{user-}. This may be useful for adding syntax highlighting to manuals for code samples. We recommend that when you give multiple arguments to @code{@@example}, you use the first argument to specify the language of the code (e.g.@: @samp{C}, @samp{lisp}, @samp{Cplusplus}). You may find uses for other arguments, such as providing a formatting hint or marking code samples for extraction and further processing, but for now nothing definitive is recommended. Perhaps this will change in future Texinfo releases. @quotation Caution Do not use tabs in the lines of an example! (Or anywhere else in Texinfo, except in verbatim environments.) @TeX{} treats tabs as single spaces, and that is not what they look like. @end quotation @node @code{@@verbatim} @nodedescription Writing a verbatim example. @section @code{@@verbatim}: Literal Text @anchor{verbatim}@c old name @findex verbatim @cindex Verbatim environment Use the @code{@@verbatim} environment for printing of text that may contain special characters or commands that should not be interpreted, such as computer input or output (@code{@@example} interprets its text as regular Texinfo commands). This is especially useful for including automatically generated files in a Texinfo manual. In general, the output will be just the same as the input. No character substitutions are made, e.g., all spaces and blank lines are significant, including tabs. The text is typeset in a fixed-width font, and not indented or filled. Write a @code{@@verbatim} command at the beginning of a line by itself. This line will disappear from the output. Mark the end of the verbatim block with an @code{@@end verbatim} command, also written at the beginning of a line by itself. The @code{@@end verbatim} will also disappear from the output. For example: @example @@verbatim @{ @var{<tab>}@@command with strange characters: @@'e expand@var{<tab>}me @} @@end verbatim @end example @noindent (where @var{<tab>} stands for a literal tab character). This produces: @verbatim { @command with strange characters: @'e expand me } @end verbatim Since the lines containing @code{@@verbatim} and @code{@@end verbatim} produce no output, typically you should put a blank line before the @code{@@verbatim} and another blank line after the @code{@@end verbatim}. Blank lines between the beginning @code{@@verbatim} and the ending @code{@@end verbatim} will appear in the output. @cindex Verbatim, small @cindex Small verbatim You can get a ``small'' verbatim by enclosing the @code{@@verbatim} in an @code{@@smallformat} environment, as shown here: @example @@smallformat @@verbatim ... still verbatim, but in a smaller font ... @@end verbatim @@end smallformat @end example Finally, a word of warning: it is not reliable to use @code{@@verbatim} inside other Texinfo constructs. See also @ref{@code{@@verbatiminclude}}. @node @code{@@lisp} @nodedescription Illustrating Lisp code. @section @code{@@lisp}: Marking a Lisp Example @anchor{lisp}@c old name @findex lisp @cindex Lisp example The @code{@@lisp} command was used for Lisp code: @example @@lisp Example lisp code @@end lisp @end example @noindent This is now synonymous with the following: @example @@example lisp Example lisp code @@end example @end example Use @code{@@lisp} to preserve information regarding the nature of the example. This is useful, for example, if you write a function that evaluates only and all the Lisp code in a Texinfo file. Then you can use the Texinfo file as a Lisp library. @node @code{@@display} @nodedescription Writing an example in the current font. @section @code{@@display}: Examples Using the Text Font @anchor{display}@c old name @findex display @cindex Display formatting The @code{@@display} command begins another kind of environment, where the font is left unchanged, not switched to typewriter as with @code{@@example}. Each line of input still produces a line of output, and the output is still indented. @display This is an example of text written between a @code{@@display} command and an @code{@@end display} command. The @code{@@display} command indents the text, but does not fill it. @end display @node @code{@@format} @nodedescription Writing an example without narrowed margins. @section @code{@@format}: Examples Using the Full Line Width @anchor{format}@c old name @findex format The @code{@@format} command is similar to @code{@@display}, except it leaves the text unindented. Like @code{@@display}, it does not select the fixed-width font. Thus, @example @group @@format This is an example of text written between a @@code@{@@@@format@} command and an @@code@{@@@@end format@} command. As you can see from this example, the @@code@{@@@@format@} command does not fill the text. @@end format @end group @end example @noindent produces @format @group This is an example of text written between a @code{@@format} command and an @code{@@end format} command. As you can see from this example, the @code{@@format} command does not fill the text. @end group @end format @node @code{@@exdent} @nodedescription Undo indentation on a line. @section @code{@@exdent}: Undoing a Line's Indentation @anchor{exdent}@c old name @findex exdent @cindex Indentation undoing The @code{@@exdent} command removes any indentation a line might have. The command is written at the beginning of a line and applies only to the text that follows the command that is on the same line. Do not use braces around the text. The text on an @code{@@exdent} line is also printed in the roman font where the output format allows this. @code{@@exdent} is usually used within examples. Thus, @example @group @@example This line follows an @@@@example command. @@exdent This line is exdented. This line follows the exdented line. The @@@@end example comes on the next line. @@end example @end group @end example @noindent produces @example @group This line follows an @@example command. @exdent This line is exdented. This line follows the exdented line. The @@end example comes on the next line. @end group @end example In practice, the @code{@@exdent} command is rarely used. Usually, you un-indent text by ending the example and returning the page to its normal width. @code{@@exdent} does not have an effect in all output formats. @node @code{@@flushleft @@flushright} @nodedescription Pushing text flush left or flush right. @section @code{@@flushleft} and @code{@@flushright} @anchor{flushleft & flushright}@c old name @findex flushleft @findex flushright @cindex Ragged right, without filling @cindex Ragged left, without filling The @code{@@flushleft} and @code{@@flushright} commands line up the ends of lines on the left and right margins of a page, but do not fill the text. The commands are written on lines of their own, without braces. The @code{@@flushleft} and @code{@@flushright} commands are ended by @code{@@end flushleft} and @code{@@end flushright} commands on lines of their own. @need 1500 For example, @example @group @@flushleft This text is written flushleft. @@end flushleft @end group @end example @noindent produces @quotation @flushleft This text is written flushleft. @end flushleft @end quotation @code{@@flushright} produces the type of indentation often used in the return address of letters. For example, @example @group @@flushright Here is an example of text written flushright. The @@code@{@@flushright@} command right justifies every line but leaves the left end ragged. @@end flushright @end group @end example @noindent produces @flushright Here is an example of text written flushright. The @code{@@flushright} command right justifies every line but leaves the left end ragged. @end flushright @node @code{@@raggedright} @nodedescription Avoiding justification on the right. @section @code{@@raggedright}: Ragged Right Text @anchor{raggedright}@c old name @findex raggedright @cindex Ragged right, with filling The @code{@@raggedright} fills text as usual, but the text is only justified on the left; the right margin is ragged. The command is written on a line of its own, without braces. The @code{@@raggedright} command is ended by @code{@@end raggedright} on a line of its own. This command only has an effect in output formats where text is justified on the left, but not in output formats where text is always set ragged right, such as Info or HTML. The @code{@@raggedright} command can be useful with paragraphs containing lists of commands with long names, when it is known in advance that justifying the text on both margins will make the paragraph look bad. An example (from elsewhere in this manual): @example @group @@raggedright Commands for double and single angle quotation marks: @@code@{@@@@guillemetleft@@@{@@@}@}, @@code@{@@@@guillemetright@@@{@@@}@}, @@code@{@@@@guillemotleft@@@{@@@}@}, @@code@{@@@@guillemotright@@@{@@@}@}, @@code@{@@@@guilsinglleft@@@{@@@}@}, @@code@{@@@@guilsinglright@@@{@@@}@}. @@end raggedright @end group @end example @noindent produces @raggedright Commands for double and single angle quotation marks: @code{@@guillemetleft@{@}}, @code{@@guillemetright@{@}}, @code{@@guillemotleft@{@}}, @code{@@guillemotright@{@}}, @code{@@guilsinglleft@{@}}, @code{@@guilsinglright@{@}}. @end raggedright @node @code{@@noindent} @nodedescription Preventing paragraph indentation. @section @code{@@noindent}: Omitting Indentation @anchor{noindent}@c old name @findex noindent @cindex Omitting indentation @cindex Suppressing indentation @cindex Indentation, omitting An example or other inclusion can break a paragraph into segments. Ordinarily, the formatters indent text that follows an example as a new paragraph. You can prevent this on a case-by-case basis by writing @code{@@noindent} at the beginning of a line, preceding the continuation text. You can also disable indentation for all paragraphs globally with @code{@@paragraphindent} (@pxref{@code{@@paragraphindent}}). Here is an example showing how to eliminate the normal indentation of the text after an @code{@@example}, a common situation: @example @group @@example This is an example @@end example @@noindent This line is not indented. As you can see, the beginning of the line is fully flush left with the line that follows after it. @end group @end example @noindent produces: @display @example This is an example @end example @noindent This line is not indented. As you can see, the beginning of the line is fully flush left with the line that follows after it. @end display The standard usage of @code{@@noindent} is just as above: at the beginning of what would otherwise be a paragraph, to eliminate the indentation that normally happens there. It can either be followed by text or be on a line by itself. There is no reason to use it in other contexts, such as in the middle of a paragraph or inside an environment (@pxref{Quotations and Examples}). You can control the number of blank lines in the Info file output by adjusting the input as desired: a line containing just @code{@@noindent} does not generate a blank line, and neither does an @code{@@end} line for an environment. Do not put braces after a @code{@@noindent} command; they are not used, since @code{@@noindent} is a command used outside of paragraphs (@pxref{Command Syntax}). @node @code{@@indent} @nodedescription Forcing paragraph indentation. @section @code{@@indent}: Forcing Indentation @anchor{indent}@c old name @findex indent @cindex Forcing indentation @cindex Inserting indentation @cindex Indentation, forcing @indent To complement the @code{@@noindent} command (see the previous section), Texinfo provides the @code{@@indent} command to force a paragraph to be indented. For instance, this paragraph (the first in this section) is indented using an @code{@@indent} command. And indeed, the first paragraph of a section is the most likely place to use @code{@@indent}, to override the normal behavior of no indentation there (@pxref{@code{@@paragraphindent}}). It can either be followed by text or be on a line by itself. As a special case, when @code{@@indent} is used in an environment where text is not filled, it produces a paragraph indentation space in the @TeX{} output. (These environments are where a line of input produces a line of output, such as @code{@@example} and @code{@@display}; for a summary of all environments, @pxref{Block Enclosing Commands}.) Do not put braces after an @code{@@indent} command; they are not used, since @code{@@indent} is a command used outside of paragraphs (@pxref{Command Syntax}). @node @code{@@cartouche} @nodedescription Drawing rounded rectangles around text. @section @code{@@cartouche}: Rounded Rectangles @anchor{cartouche}@c old name @findex cartouche @cindex Box with rounded corners @cindex Rounded rectangles, around text Where the output format allows, the @code{@@cartouche} command draws a box with rounded corners around its contents. In HTML, a normal rectangle is drawn. You can use this command to isolate a portion of the manual from the main flow. You can also further highlight an example or quotation with @code{@@cartouche}. For instance, you could write a manual in which one type of example is surrounded by a cartouche for emphasis. For example, @example @@cartouche @@example % pwd /usr/local/share/emacs @@end example @@end cartouche @end example @noindent surrounds the two-line example with a box with rounded corners, in the printed manual. The output from the example looks like this (if you're reading this in Info, you'll see the @code{@@cartouche} had no effect): @cartouche @example % pwd /usr/local/share/emacs @end example @end cartouche @code{@@cartouche} takes one optional argument, given on the remainder of the line. This text, if present, is the cartouche title. It is output in bold or otherwise emphasized at the beginning of the cartouche, and is centered in some output formats. The following example illustrates a cartouche with a title: @example @@cartouche Important Text explaining something important out of the main flow of the text. @@end cartouche @end example The cartouche with a title looks like this: @cartouche Important Text explaining something important out of the main flow of the text. @end cartouche A cartouche is output on a single page in printed output, similarly to @code{@@group} (@pxref{@code{@@group}}). @node small @nodedescription Examples in a smaller font. @section @code{@@small@dots{}} Block Commands @findex smallexample @findex smallformat @findex smalllisp @findex smallquotation @findex smalldisplay @findex smallindentedblock @cindex Small examples @cindex Examples in smaller fonts @cindex Quotations in smaller fonts @cindex Lisp examples in smaller fonts In addition to the regular @code{@@example} and similar commands, Texinfo has ``small'' example-style commands. These are @code{@@smallquotation}, @code{@@smallindentedblock}, @code{@@smalldisplay}, @code{@@smallexample}, @code{@@smallformat}, and @code{@@smalllisp}. In most output formats, the @code{@@small@dots{}} commands are equivalent to their non-small companion commands. In printed output, however, the @code{@@small@dots{}} commands typeset text in a smaller font than the non-small example commands. Thus, for instance, code examples can contain longer lines and still fit on a page without needing to be rewritten. Mark the end of a @code{@@small@dots{}} block with a corresponding @code{@@end small@dots{}}. For example, pair @code{@@smallexample} with @code{@@end smallexample}. Here is an example of the font used by the @code{@@smallexample} command (in most output formats, the output will be the same as usual): @smallexample @dots{} to make sure that you have the freedom to distribute copies of free software (and charge for this service if you wish), that you receive source code or can get it if you want it, that you can change the software or use pieces of it in new free programs; and that you know you can do these things. @end smallexample The @code{@@small@dots{}} commands use the same font style as their normal counterparts: @code{@@smallexample} and @code{@@smalllisp} use a fixed-width font, and everything else uses the regular font. They also have the same behavior in other respects---whether filling is done and whether margins are narrowed. As a general rule, it's better to just use the regular commands (such as @code{@@example} instead of @code{@@smallexample}), unless you have a good reason for it. @node Lists and Tables @nodedescription Itemized or numbered lists, and tables. @chapter Lists and Tables @cindex Making lists and tables @cindex Lists and tables, making @cindex Tables and lists, making Texinfo has several ways of making lists and tables. Lists can be bulleted or numbered; two-column tables can highlight the items in the first column; multi-column tables are also supported. @node Introducing Lists @nodedescription Texinfo formats lists for you. @section Introducing Lists Texinfo automatically indents the text in lists or tables, and numbers an enumerated list. This last feature is useful if you modify the list, since you do not need to renumber it yourself. Numbered lists and tables begin with the appropriate @@-command at the beginning of a line, and end with the corresponding @code{@@end} command on a line by itself. The table and itemized-list commands also require that you write formatting information on the same line as the beginning @@-command. Begin an enumerated list, for example, with an @code{@@enumerate} command and end the list with an @code{@@end enumerate} command. Begin an itemized list with an @code{@@itemize} command, followed on the same line by a formatting command such as @code{@@bullet}, and end the list with an @code{@@end itemize} command. Precede each element of a list with an @code{@@item} or @code{@@itemx} command. @sp 1 @noindent Here is an itemized list of the different kinds of table and lists: @itemize @bullet @item Itemized lists with and without bullets. @item Enumerated lists, using numbers or letters. @item Two-column tables with highlighting. @end itemize @sp 1 @noindent Here is an enumerated list with the same items: @enumerate @item Itemized lists with and without bullets. @item Enumerated lists, using numbers or letters. @item Two-column tables with highlighting. @end enumerate @sp 1 @noindent And here is a two-column table with the same items and their @w{@@-commands}: @table @code @item @@itemize Itemized lists with and without bullets. @item @@enumerate Enumerated lists, using numbers or letters. @item @@table @itemx @@ftable @itemx @@vtable Two-column tables, optionally with indexing. @end table @node @code{@@itemize} @nodedescription How to construct a simple list. @section @code{@@itemize}: Making an Itemized List @anchor{itemize}@c old name @findex itemize @cindex Itemization The @code{@@itemize} command produces a sequence of ``items'', each starting with a bullet or other mark inside the left margin, and generally indented. @cindex @code{@@w}, for blank items Begin an itemized list by writing @code{@@itemize} at the beginning of a line. Follow the command, on the same line, with a character or a Texinfo command that generates a mark. Usually, you will use @code{@@bullet} after @code{@@itemize}, but you can use @code{@@minus}, or any command or character that results in a single character in the Info file. (When you write the mark command such as @code{@@bullet} after an @code{@@itemize} command, you may omit the @samp{@{@}}.) If you don't specify a mark command, the default is @code{@@bullet}. If you don't want any mark at all, but still want logical items, use @code{@@w@{@}} (in this case the braces are required). @findex item @r{in @code{@@itemize}} After the @code{@@itemize}, write your items, each starting with @code{@@item}. Text can follow on the same line as the @code{@@item}. The text of an item can continue for more than one paragraph. There should be at least one @code{@@item} inside the @code{@@itemize} environment. If none are present, @code{texi2any} gives a warning. If you just want indented text and not a list of items, use @code{@@indentedblock}; @pxref{@code{@@indentedblock}}. Index entries and comments that are given before an @code{@@item} including the first, are automatically moved (internally) to after the @code{@@item}, so the output is as expected. Historically this has been a common practice. Usually, you should put a blank line between items. This puts a blank line in the Info file. (@TeX{} inserts the proper vertical space in any case.) Except when the entries are very brief, these blank lines make the list look better. Here is an example of the use of @code{@@itemize}, followed by the output it produces. @code{@@bullet} produces an @samp{*} in Info and a round dot in other output formats. @example @group @@itemize @@bullet @@item Some text for foo. @@item Some text for bar. @@end itemize @end group @end example @noindent This produces: @quotation @itemize @bullet @item Some text for foo. @item Some text for bar. @end itemize @end quotation Itemized lists may be embedded within other itemized lists. Here is a list marked with dashes embedded in a list marked with bullets: @example @group @@itemize @@bullet @@item First item. @@itemize @@minus @@item Inner item. @@item Second inner item. @@end itemize @@item Second outer item. @@end itemize @end group @end example @noindent This produces: @quotation @itemize @bullet @item First item. @itemize @minus @item Inner item. @item Second inner item. @end itemize @item Second outer item. @end itemize @end quotation @node @code{@@enumerate} @nodedescription How to construct a numbered list. @section @code{@@enumerate}: Making a Numbered or Lettered List @anchor{enumerate}@c old name @findex enumerate @cindex Enumeration @code{@@enumerate} is like @code{@@itemize} (@pxref{@code{@@itemize}}), except that the labels on the items are successive integers or letters instead of bullets. Write the @code{@@enumerate} command at the beginning of a line. The command does not require an argument, but accepts either a number or a letter as an option. Without an argument, @code{@@enumerate} starts the list with the number @samp{1}. With a numeric argument, such as @samp{3}, the command starts the list with that number. With an upper- or lowercase letter, such as @samp{a} or @samp{A}, the command starts the list with that letter. Write the text of the enumerated list in the same way as an itemized list: write a line starting with @code{@@item} at the beginning of each item in the enumeration. It is ok to have text following the @code{@@item}, and the text for an item can continue for several paragraphs. You should put a blank line between entries in the list. This generally makes it easier to read the Info file. @need 1500 Here is an example of @code{@@enumerate} without an argument: @example @group @@enumerate @@item Underlying causes. @@item Proximate causes. @@end enumerate @end group @end example @noindent This produces: @enumerate @item Underlying causes. @item Proximate causes. @end enumerate @sp 1 Here is an example with an argument of @kbd{3}: @sp 1 @example @group @@enumerate 3 @@item Predisposing causes. @@item Precipitating causes. @@item Perpetuating causes. @@end enumerate @end group @end example @noindent This produces: @enumerate 3 @item Predisposing causes. @item Precipitating causes. @item Perpetuating causes. @end enumerate @sp 1 Here is a summary: @sp 1 @enumerate a @item @code{@@enumerate} Without an argument, produce a numbered list, with the first item numbered@tie{}1. @item @code{@@enumerate @var{unsigned-integer}} With an (unsigned) numeric argument, start a numbered list with that number. You can use this to continue a list that you interrupted with other text. @item @code{@@enumerate @var{upper-case-letter}} With an uppercase letter as argument, start a list in which each item is marked by a letter, beginning with that uppercase letter. @item @code{@@enumerate @var{lower-case-letter}} With a lowercase letter as argument, start a list in which each item is marked by a letter, beginning with that lowercase letter. @end enumerate You can also nest enumerated lists, as in an outline. @node Two-column Tables @nodedescription How to construct a two-column table. @section Making a Two-column Table @cindex Tables, making two-column @findex table @code{@@table} is similar to @code{@@itemize} (@pxref{@code{@@itemize}}), but allows you to specify a name or heading line for each item. The @code{@@table} command is used to produce two-column tables, and is especially useful for glossaries, explanatory exhibits, and command-line option summaries. @node @code{@@table} @nodedescription How to construct a two-column table. @subsection Using the @code{@@table} Command @anchor{table}@c old name @cindex Definition lists, typesetting Use the @code{@@table} command to produce a two-column table. This command is typically used when you have a list of items and a brief text with each one, such as a list of definitions. Write the @code{@@table} command at the beginning of a line, after a blank line, and follow it on the same line with an argument that is an `indicating' command, such as @code{@@code}, @code{@@samp}, @code{@@var}, @code{@@option}, or @code{@@kbd} (@pxref{Indicating}). This command will be applied to the text in the first column. For example, @code{@@table @@code} will cause the text in the first column to be output as if it had been the argument to a @code{@@code} command. @anchor{@code{@@asis}}@c command name with @, for consistency @findex asis You may use the @code{@@asis} command as an argument to @code{@@table}. @code{@@asis} is a command that does nothing: if you use this command after @code{@@table}, the first column entries are output without added highlighting (``as is''). The @code{@@table} command works with other commands besides those explicitly mentioned here. However, you can only use predefined Texinfo commands that take an argument in braces. You cannot reliably use a new command defined with @code{@@macro}, although an @code{@@alias} (for a suitable predefined command) is acceptable. @xref{Defining New Texinfo Commands}. @findex item @r{in @code{@@table}} Begin each table entry with an @code{@@item} command at the beginning of a line. Write the text for the first column on the same line as the @code{@@item} command. Write the text for the second column on the line following the @code{@@item} line and on subsequent lines. You may write as many lines of supporting text as you wish, even several paragraphs. But only the text on the same line as the @code{@@item} will be placed in the first column (including any footnotes). You do not need to type anything for an empty second column. Normally, you should put a blank line between table entries. This puts a blank line in the Info file, which looks better unless the entries are very brief. End the table with a line consisting of @code{@@end table}. Follow the end of the table by a blank line for consistent formatting across output formats. @c TeX aloways starts a new paragraph after the table @need 1500 For example, the following table highlights the text in the first column with the @code{@@samp} command: @example @group @@table @@samp @@item foo This is the text for @@samp@{foo@}. @@item bar Text for @@samp@{bar@}. @@end table @end group @end example @noindent This produces: @table @samp @item foo This is the text for @samp{foo}. @item bar Text for @samp{bar}. @end table If you want to list two or more named items with a single block of text, use the @code{@@itemx} command. (@xref{@code{@@itemx}}.) The @code{@@table} command (@pxref{@code{@@table}}) is not supported inside @code{@@display}. Since @code{@@display} is line-oriented, it doesn't make sense to use them together. If you want to indent a table, try @code{@@quotation} (@pxref{@code{@@quotation}}) or @code{@@indentedblock} (@pxref{@code{@@indentedblock}}). @node @code{@@ftable @@vtable} @nodedescription Automatic indexing for two-column tables. @subsection @code{@@ftable} and @code{@@vtable} @anchor{ftable vtable}@c old name @findex ftable @findex vtable @cindex Tables with indexing @cindex Indexing table entries automatically The @code{@@ftable} and @code{@@vtable} commands are the same as the @code{@@table} command except that @code{@@ftable} automatically enters each of the items in the first column of the table into the index of functions and @code{@@vtable} automatically enters each of the items in the first column of the table into the index of variables. This simplifies the task of creating indices. Only the items on the same line as the @code{@@item} or @code{@@itemx} commands are indexed, and they are indexed in exactly the form that they appear on that line. @xref{Indices}, for more information about indices. Begin a two-column table using @code{@@ftable} or @code{@@vtable} by writing the @@-command at the beginning of a line, followed on the same line by an argument that is a Texinfo command such as @code{@@code}, exactly as you would for a @code{@@table} command; and end the table with an @code{@@end ftable} or @code{@@end vtable} command on a line by itself. See the example for @code{@@table} in the previous section. @node @code{@@itemx} @nodedescription How to put more entries in the first column. @subsection @code{@@itemx}: Second and Subsequent Items @anchor{itemx}@c old name @cindex Two named items for @code{@@table} @findex itemx Use the @code{@@itemx} command inside a table when you have two or more first column entries for the same item, each of which should appear on a line of its own. Use @code{@@item} for the first entry, and @code{@@itemx} for all subsequent entries; @code{@@itemx} must always follow an @code{@@item} command, with no blank line intervening. The @code{@@itemx} command works exactly like @code{@@item} except that it does not generate extra vertical space above the first column text in some output formats. If you have multiple consecutive @code{@@itemx} commands, do not insert any blank lines between them. For example, @example @group @@table @@code @@item upcase @@itemx downcase These two functions accept a character or a string as argument, and return the corresponding uppercase (lowercase) character or string. @@end table @end group @end example @noindent This produces: @table @code @item upcase @itemx downcase These two functions accept a character or a string as argument, and return the corresponding uppercase (lowercase) character or string. @end table @noindent (Note also that this example illustrates multi-line supporting text in a two-column table.) @node Multi-column Tables @nodedescription How to construct generalized tables. @section @code{@@multitable}: Multi-column Tables @findex multitable @cindex Tables, making multi-column @code{@@multitable} allows you to construct tables with any number of columns, with each column having any width you like. You define the column widths on the @code{@@multitable} line itself, and write each row of the actual table following an @code{@@item} command, with columns separated by a @code{@@tab} command. Finally, @code{@@end multitable} completes the table. Details in the sections below. @node Multitable Column Widths @nodedescription Defining multitable column widths. @subsection Multitable Column Widths @cindex Multitable column widths @cindex Column widths, defining for multitables @cindex Widths, defining multitable column You can define the column widths for a multitable in two ways: as fractions of the line length; or with a prototype row. Mixing the two methods is not supported. In either case, the widths are defined entirely on the same line as the @code{@@multitable} command. @enumerate @item @findex columnfractions @cindex Line length, column widths as fraction of To specify column widths as fractions of the line length, write @code{@@columnfractions} and the decimal numbers (presumably less than 1; a leading zero is allowed and ignored) after the @code{@@multitable} command, as in: @example @@multitable @@columnfractions .33 .33 .33 @end example The fractions need not add up exactly to 1.0, as these do not. This allows you to produce tables that do not need the full line length. When using @code{@@columnfractions}, the leftmost column may appear slightly wider than you might expect, relative to the other columns. This is due to spacing between columns being included in the width of the other columns. @item @cindex Prototype row, column widths defined by To specify a prototype row, write the longest entry for each column enclosed in braces after the @code{@@multitable} command. For example: @example @@multitable @{some text for column one@} @{for column two@} @end example @noindent The first column will then have the width of the typeset `some text for column one', and the second column the width of `for column two'. The prototype entries need not appear in the table itself. Although we used simple text in this example, the prototype entries can contain Texinfo commands; markup commands such as @code{@@code} are particularly likely to be useful. Prototype rows have no effect in HTML output. @end enumerate @node Multitable Rows @nodedescription Defining multitable rows, with examples. @subsection Multitable Rows @cindex Multitable rows @cindex Rows, of a multitable @findex item @r{in @code{@@multitable}} @findex tab After the @code{@@multitable} command defining the column widths (see the previous section), you begin each row in the body of a multitable with @code{@@item}, and separate the column entries with @code{@@tab}. Line breaks are not special within the table body, and you may break input lines in your source file as necessary. @findex headitem @cindex Heading row, in table @cindex @code{<thead>} HTML/DocBook tag You can also use @code{@@headitem} instead of @code{@@item} to produce a @dfn{heading row}. The @TeX{} output for such a row is in bold, and the HTML and DocBook output uses the @code{<thead>} tag. In Info, the heading row is followed by a separator line made of dashes (@samp{-} characters). @findex headitemfont @cindex Font for multitable heading rows The command @code{@@headitemfont} can be used in templates when the entries in a @code{@@headitem} row need to be used in a template. It is a synonym for @code{@@b}, but using @code{@@headitemfont} avoids any dependency on that particular font style, in case we provide a way to change it in the future. Here is a complete example of a multi-column table (the text is from @cite{The GNU Emacs Manual}, @pxref{Split Window,, Splitting Windows, emacs, The GNU Emacs Manual}): @example @@multitable @@columnfractions .15 .45 .4 @@headitem Key @@tab Command @@tab Description @@item C-x 2 @@tab @@code@{split-window-vertically@} @@tab Split the selected window into two windows, with one above the other. @@item C-x 3 @@tab @@code@{split-window-horizontally@} @@tab Split the selected window into two windows positioned side by side. @@item C-Mouse-2 @@tab @@tab In the mode line or scroll bar of a window, split that window. @@end multitable @end example @noindent produces: @multitable @columnfractions .15 .45 .4 @headitem Key @tab Command @tab Description @item C-x 2 @tab @code{split-window-vertically} @tab Split the selected window into two windows, with one above the other. @item C-x 3 @tab @code{split-window-horizontally} @tab Split the selected window into two windows positioned side by side. @item C-Mouse-2 @tab @tab In the mode line or scroll bar of a window, split that window. @end multitable @node Special Displays @nodedescription Floating figures and footnotes. @chapter Special Displays @cindex Special displays The commands in this chapter allow you to write text that is specially displayed (output format permitting), outside of the normal document flow. One set of such commands is for creating ``floats'', that is, figures, tables, and the like, set off from the main text, possibly numbered, captioned, and/or referred to from elsewhere in the document. Images are often included in these displays. Another group of commands is for creating footnotes in Texinfo. @node Floats @nodedescription Figures, tables, and the like. @section Floats @cindex Floats A @dfn{float} is a display which is set off from the main text. It is typically labeled as being a ``Figure'', ``Table'', ``Example'', or some similar type. @cindex Floating, not yet implemented A float is so-named because, in principle, it can be moved to the bottom or top of the current page, or to a following page, in the printed output. (Floating does not make sense in other output formats.) In every output format except for @LaTeX{}, however, this floating is unfortunately not yet implemented. Instead, the floating material is simply output at the current location, more or less as if it were an @code{@@group} (@pxref{@code{@@group}}). @node @code{@@float} @nodedescription Producing floating material. @subsection @code{@@float} [@var{type}][,@var{label}]: Floating Material @anchor{float}@c old name @findex float @cindex Float environment To produce floating material, enclose the material you want to be displayed separate between @code{@@float} and @code{@@end float} commands, on lines by themselves. Floating material often uses @code{@@image} to display an already-existing graphic (@pxref{Images}), or @code{@@multitable} to display a table (@pxref{Multi-column Tables}). However, the contents of the float can be anything. Here's an example with simple text: @example @@float Figure,fig:ex1 This is an example float. @@end float @end example @noindent And the output: @float Figure,fig:ex1 This is an example float. @end float As shown in the example, @code{@@float} takes two arguments (separated by a comma), @var{type} and @var{label}. Both are optional. @table @var @item type Specifies the sort of float this is; typically a word such as ``Figure'', ``Table'', etc. If this is not given, and @var{label} is, any cross-referencing will simply use a bare number. @item label Specifies a cross-reference label for this float. If given, this float is automatically given a number, and will appear in any @c TODO LaTeX: figure only appears in the @listoffloats if there is a caption @code{@@listoffloats} output (@pxref{@code{@@listoffloats}}). Cross references to @var{label} are allowed. For example, @samp{see @@ref@{fig:ex1@}} will produce see @ref{fig:ex1}. @cindex Floats @subentry making unnumbered @cindex Unnumbered float, creating On the other hand, if @var{label} is not given, then the float will not be numbered and consequently will not appear in the @code{@@listoffloats} output or be cross-referenceable. @end table @noindent Ordinarily, you specify both @var{type} and @var{label}, to get a labeled and numbered float. In the @LaTeX{} output, code loading the @code{float} package is output in the preamble if @code{@@float} are present. A @code{@@float} with type @samp{figure} or @samp{table} (case insensitive) is already defined by the package. Other float types lead to the definition of a new float environment, with names based on the @code{@@float} type with anything else than letters and @samp{-} removed. @cindex Floats @subentry numbering of @cindex Numbering of floats In Texinfo, all floats are numbered in the same way: with the chapter number (or appendix letter), a period, and the float number, which simply counts 1, 2, 3, @dots{}, and is reset at each chapter. Each float type is counted independently. Floats within an @code{@@unnumbered}, or outside of any chapter, are simply numbered consecutively from 1. These numbering conventions are not, at present, changeable. @node @code{@@caption @@shortcaption} @nodedescription Specifying descriptions for floats. @subsection @code{@@caption} & @code{@@shortcaption} @anchor{caption shortcaption}@c old name @findex caption @findex shortcaption @cindex Captions, for floats @cindex Short captions, for lists of floats You may write a @code{@@caption} anywhere within a @code{@@float} environment, to define a caption for the float. It is not allowed in any other context. @code{@@caption} takes a single argument, enclosed in braces. Here's an example: @example @@float An example float, with caption. @@caption@{Caption for example float.@} @@end float @end example @noindent The output is: @float An example float, with caption. @caption{Caption for example float.} @end float @code{@@caption} can appear anywhere within the float; it is not processed until the @code{@@end float}. The caption text is usually a sentence or two, but may consist of several paragraphs if necessary. In the output, the caption always appears below the float; this is not currently changeable. It is preceded by the float type and/or number, as specified to the @code{@@float} command (see the previous section). The @code{@@shortcaption} command likewise may be used only within @code{@@float}, and takes a single argument in braces. The short caption text is used instead of the caption text in a list of floats (see the next section). Thus, you can write a long caption for the main document, and a short title to appear in the list of floats. For example: @example @@float ... as above ... @@shortcaption@{Text for list of floats.@} @@end float @end example The text for @code{@@shortcaption} may not contain comments (@code{@@c}), verbatim text (@code{@@verb}), environments such as @code{@@example}, footnotes (@code{@@footnote}), multiple paragraphs, or other complex constructs. The same constraints apply to @code{@@caption} unless there is a @code{@@shortcaption}. In @LaTeX{} a multi-paragraph @code{@@caption} will lead to an error when formatted, unless there is a @code{@@shortcaption}. @node @code{@@listoffloats} @nodedescription A table of contents for floats. @subsection @code{@@listoffloats}: Tables of Contents for Floats @anchor{listoffloats}@c old name @findex listoffloats @cindex List of floats @cindex Floats @subentry list of @cindex Table of contents, for floats You can write a @code{@@listoffloats} command to generate a list of floats for a given float type (@pxref{@code{@@float}}), analogous to the document's overall table of contents. Typically, it is written in its own @code{@@unnumbered} node to provide a heading and structure, rather like @code{@@printindex} (@pxref{Printing Indices & Menus}). @code{@@listoffloats} takes one optional argument, the float type. Here's an example: @example @@node List of Figures @@unnumbered List of Figures @@listoffloats Figure @end example @noindent Without any argument, @code{@@listoffloats} generates a list of floats for which no float type was specified, i.e., no first argument to the @code{@@float} command (@pxref{@code{@@float}}). Here's what the output from @code{@@listoffloats} looks like, given the example figure earlier in this chapter: @ifinfo @display * Figure 12.1: fig:ex1. @end display @end ifinfo @ifnotinfo @listoffloats Figure @end ifnotinfo Usually, each line in the list of floats contains the float type (if any), the float number, and the caption, if any---the @code{@@shortcaption} argument, if it was specified, else the @code{@@caption} argument. The page number may also be included, depending on output format. Unnumbered floats (those without cross-reference labels) are omitted from the list of floats. The formatting of @code{@@listoffloats} depends on the output format. In Info, for example, a @code{@@listoffloats} is formatted as a menu. In @LaTeX{} output, @code{\listoffigures} is output for the @samp{figure} (case insensitive) float type, @code{\listoftables} is output for the @samp{table} (case insensitive) float type. For other float types, a specific @code{\listof} command is output. @node Images @nodedescription Including graphics and images. @section Inserting Images @cindex Images @cindex Pictures, inserting @findex image You can insert an image given in an external file with the @code{@@image} command. Although images can be used anywhere, including the middle of a paragraph, we describe them in this chapter since they are most often part of a displayed figure or example. @node Image Syntax @subsection Image Syntax Here is the synopsis of the @code{@@image} command: @example @@image@{@var{filename}@r{[,} @var{width}@r{[,} @var{height}@r{[,} @var{alttext}@r{[, }@var{extension}@r{]]]]}@} @end example @cindex Formats for images @cindex Image formats The @var{filename} argument is mandatory, and must not have an extension, because the different processors support different formats: @itemize @bullet @item @pindex eps image format @TeX{} (DVI output) reads the file @file{@var{filename}.eps} (Encapsulated PostScript format). @item @pindex pdftex@r{, and images} @pindex png image format @pindex jpeg image format @pindex pdf image inclusions @TeX{} (PDF output) reads @file{@var{filename}.pdf}, @file{@var{filename}.png}, @file{@var{filename}.jpg}, or @file{@var{filename}.jpeg} (in that order). It also tries uppercase versions of the extensions. The PDF format does not support EPS images, so such must be converted first. @item In Info, @file{@var{filename}.txt} is included verbatim (more or less as if it were in @code{@@verbatim}). The Info output may also include a reference to @file{@var{filename}.png} or @file{@var{filename}.jpg}. (See below.) @item In HTML, a reference to @file{@var{filename}.png}, @file{@var{filename}.jpg}, @file{@var{filename}.jpeg} or @file{@var{filename}.gif} (in that order) is output. If none of those exist, it gives an error, and outputs a reference to @file{@var{filename}.jpg} anyway. @item @cindex SVG images, used in DocBook In DocBook, references to @file{@var{filename}.eps}, @file{@var{filename}.gif}, @file{@var{filename}.jpeg}, @file{@var{filename}.jpg}, @file{@var{filename}.pdf}, @file{@var{filename}.png} and @file{@var{filename}.svg} are output, for every file found. Also, @file{@var{filename}.txt} is included verbatim, if present. (The subsequent DocBook processor is supposed to choose the appropriate one.) @item For @LaTeX{}, @file{@var{filename}} without any extension is used; the subsequent @LaTeX{} processor is supposed to choose the appropriate image type. @item For Info and HTML output, the optional fifth argument @var{extension} to @code{@@image} is used for the file extension, if it is specified and the file is found. Any leading period should be included in @var{extension}. For example: @pindex XPM image format @example @@image@{foo,,,,.xpm@} @end example @end itemize If you want to install image files for use by Info readers too, we recommend putting them in a subdirectory like @samp{@var{foo}-figures} for a package @var{foo}. Copying the files into @code{$(infodir)/@var{foo}-figures/} should be done in your @code{Makefile}. The @var{width} and @var{height} arguments are described in the next section. If an image is the first thing in a paragraph and followed by more text, then you should precede the @code{@@image} command with @code{@@indent} or @code{@@noindent} to indicate the beginning of paragraph formatting. This is especially important for @TeX{} output to get correct paragraph indentation. Use @code{@@center} to center an image (@pxref{@code{@@titlefont @@center @@sp}}). @cindex Alt attribute for images @cindex Images @subentry alternate text for @cindex @sortas{-} -@r{ (in image alt string)} For HTML output, the @dfn{alt attribute} for inline images is set to the optional @var{alttext} (fourth) argument to @code{@@image}, if supplied. If not supplied, the full file name of the image being displayed is used. The @var{alttext} is processed as Texinfo text, so special characters such as @samp{"} and @samp{<} and @samp{&} are escaped in the HTML output; also, you can get an empty @code{alt} string with @code{@@-} (a command that produces no output; @pxref{@code{@@- @@hyphenation}}). For Info output, the @var{alttext} string is also processed as Texinfo text and output. In this case, @samp{\} is escaped as @samp{\\} and @samp{"} as @samp{\"}; no other escapes are done. In Info output, a reference to the binary image file is written (trying @var{filename} suffixed with @file{@var{extension}}, @file{@var{.extension}}, @file{.png}, or @file{.jpg}, in that order) if one exists. The @file{.txt} file is also literally included, if one exists. This way, Info readers which can display images (such as the Emacs Info browser, running under X) can do so, whereas Info readers which can only use text (such as the standalone Info reader) can display the textual version. @c Texinfo version 4.6 was released in 2003 @ignore @cindex @samp{^@@^H} for images in Info The implementation of this is to put the following construct into the Info output: @example ^@@^H[image src="@var{binaryfile}" text="@var{txtfile}" alt="@var{alttext} ... ^@@^H] @end example @noindent where @samp{^@@} and @samp{^H} stand for the actual null and backspace control characters. If one of the files is not present, the corresponding argument is omitted. The reason for mentioning this here is that older Info browsers (this feature was introduced in Texinfo version 4.6) will display the above literally, which, although not pretty, should not be harmful. @end ignore @node Image Scaling @subsection Image Scaling @cindex Images @subentry scaling @cindex Scaling images @cindex Width of images @cindex Height of images @cindex Aspect ratio of images @cindex Distorting images The optional @var{width} and @var{height} arguments to the @code{@@image} command (see the previous section) specify the size to which to scale the image. They are only taken into account in printed output. In @TeX{}, if neither is specified, the image is presented in its natural size (given in the file); if only one is specified, the other is scaled proportionately; and if both are specified, both are respected, thus likely distorting the original image by changing its aspect ratio. @cindex Dimensions and image sizes The @var{width} and @var{height} may be specified using any valid @TeX{} dimension, namely: @table @asis @item pt @cindex Points (dimension) point (72.27pt = 1in) @item pc @cindex Picas pica (1pc = 12pt) @item bp @cindex Big points big point (72bp = 1in) @item in @cindex Inches inch @item cm @cindex Centimeters centimeter (2.54cm = 1in) @item mm @cindex Millimeters millimeter (10mm = 1cm) @item dd @cindex Did@^ot points did@^ot point (1157dd = 1238pt) @item cc @cindex Ciceros cicero (1cc = 12dd) @item sp @cindex Scaled points scaled point (65536sp = 1pt) @end table @pindex ridt.eps For example, the following will scale a file @file{ridt.eps} to one inch vertically, with the width scaled proportionately: @example @@image@{ridt,,1in@} @end example @pindex epsf.tex For @code{@@image} to work with @TeX{}, the file @file{epsf.tex} must be installed somewhere that @TeX{} can find it. (The standard location is @file{@var{texmf}/tex/generic/dvips/epsf.tex}, where @var{texmf} is a root of your @TeX{} directory tree.) This file is included in the Texinfo distribution and is also available from @uref{ftp://tug.org/tex/epsf.tex}, among other places. @code{@@image} can be used within a line as well as for displayed figures. Therefore, if you intend it to be displayed, be sure to leave a blank line before the command, or the output will run into the preceding text. Image scaling is presently implemented only in printed output, not in any other sort of output. @node Footnotes @nodedescription Writing footnotes. @section Footnotes @cindex Footnotes @findex footnote A @dfn{footnote} is for a reference that documents or elucidates the primary text.@footnote{A footnote should complement or expand upon the primary text, but a reader should not need to read a footnote to understand the primary text. For a thorough discussion of footnotes, see @cite{The Chicago Manual of Style}, which is published by the University of Chicago Press.} Footnotes are distracting; use them sparingly at most, and it is best to avoid them completely. Standard bibliographical references are usually better placed in a bibliography at the end of a document instead of in footnotes throughout. @node Footnote Commands @nodedescription How to write a footnote in Texinfo. @subsection Footnote Commands In Texinfo, footnotes are created with the @code{@@footnote} command. This command is followed immediately by a left brace, then by the text of the footnote, and then by a terminating right brace. Footnotes may be of any length (they will be broken across pages if necessary), but are usually short. The template is: @example ordinary text@@footnote@{@var{text of footnote}@} @end example As shown here, the @code{@@footnote} command should come right after the text being footnoted, with no intervening space; otherwise, the footnote marker might end up starting a line. For example, this clause is followed by a sample footnote@footnote{Here is the sample footnote.}; in the Texinfo source, it looks like this: @example @dots{}a sample footnote@@footnote@{Here is the sample footnote.@}; in the Texinfo source@dots{} @end example As you can see, this source includes two punctuation marks next to each other; in this case, @samp{.@};} is the sequence. This is normal (the first ends the footnote and the second belongs to the sentence being footnoted), so don't worry that it looks odd. (Another style, perfectly acceptable, is to put the footnote after punctuation belonging to the sentence, as in @samp{;@@footnote@{...}.) In printed output formats, the reference mark for a footnote is a small, superscripted number; the text of the footnote appears at the bottom of the page, below a horizontal line. In Info, the reference mark for a footnote is a pair of parentheses with the footnote number between them, like this: @samp{(1)}. The reference mark is followed by a cross-reference link to the footnote text if footnotes are put in separate nodes (@pxref{Footnote Styles}). In the HTML output, footnote references are generally marked with a small, superscripted number which is rendered as a hypertext link to the footnote text. @cindex Critical editions @cindex Nested footnotes Footnotes cannot be nested, and cannot appear in section headings of any kind or other ``unusual'' places. A final tip: footnotes in the argument of an @code{@@item} command for an @code{@@table} must be entirely on the same line as the @code{@@item} (as usual). @xref{Two-column Tables}. @node Footnote Styles @nodedescription Controlling how footnotes appear. @subsection Footnote Styles Online formats have two footnote styles, which determine where the text of the footnote is located, the @samp{end} and @samp{separate} footnote style. @table @samp @cindex @samp{end} node footnote style @cindex Footnote style @subentry @samp{end} @item end For Info, in the @samp{end} node style, all the footnotes for a single node are placed at the end of that node. The footnotes are separated from the rest of the node by a line of dashes with the word @samp{Footnotes} within it. Each footnote begins with an @samp{(@var{n})} reference mark. @need 700 @noindent Here is an example of the Info output for a single footnote in the end-of-node style: @example @group --------- Footnotes --------- (1) Here is a sample footnote. @end group @end example In HTML, when the footnote style is @samp{end}, or if the output is not split, footnotes are put at the end of each output file. @cindex @samp{separate} footnote style @cindex Footnote style @subentry @samp{separate} @item separate For Info, in the @samp{separate} node style, all the footnotes for a single node are placed in an automatically constructed node of their own. In this style, a ``footnote reference'' follows each @samp{(@var{n})} reference mark in the body of the node. The footnote reference is actually a cross-reference which you use to reach the footnote node. The name of the node with the footnotes is constructed by appending @w{@samp{-Footnotes}} to the name of the node that contains the footnotes. (Consequently, the footnotes' node for the @file{Footnotes} node is @w{@file{Footnotes-Footnotes}}!) The footnotes' node has an `Up' node pointer that leads back to its parent node. @noindent Here is how the first footnote in this manual looks after being formatted for Info in the separate node style: @example @group File: texinfo.info Node: Overview-Footnotes, Up: Overview (1) The first syllable of "Texinfo" is pronounced like "speck", not "hex". @dots{} @end group @end example In HTML, when the footnote style is @samp{separate}, and the output is split, footnotes are placed in a separate file. @end table Unless your document has long and important footnotes (as in, say, Gibbon's @cite{Decline and Fall @dots{}}), we recommend the @samp{end} style, as it is simpler for readers to follow. @findex footnotestyle Use the @code{@@footnotestyle} command to specify the footnote style. Write this command at the beginning of a line followed by an argument, either @samp{end} for the end node style or @samp{separate} for the separate node style. @need 700 For example, @example @@footnotestyle end @end example @noindent or @example @@footnotestyle separate @end example Write a @code{@@footnotestyle} command in the Texinfo file preamble. @node Indices @nodedescription Creating indices. @chapter Indices @cindex Indices Using Texinfo, you can generate indices without having to sort and collate entries manually. In an index, the entries are listed in alphabetical order, together with information on how to find the discussion of each entry. In a printed manual, this information consists of page numbers. In other formats, links to the index entries location or to the associated nodes are generated. Texinfo provides several predefined kinds of indices: an index for functions, an index for variables, an index for concepts, and so on. You can combine indices or use them for other than their canonical purpose. Lastly, you can define your own new indices. @node Predefined Indices @nodedescription Use different indices for different kinds of entries. @section Predefined Indices Texinfo provides six predefined indices. Here are their nominal meanings, abbreviations, and the corresponding index entry commands: @table @samp @item cp @cindex @code{cp} (concept) index @findex cindex @findex cpindex (@code{@@cindex}) Concept index, for general concepts. @item fn @cindex @code{fn} (function) index @findex findex @findex fnindex (@code{@@findex}) Function index, for function and function-like names (such as entry points of libraries). @item ky @cindex @code{ky} (keystroke) index @findex kindex @findex kyindex (@code{@@kindex}) Keystroke index, for keyboard commands. @item pg @cindex @code{pg} (program) index @findex pindex @findex pgindex (@code{@@pindex}) Program index, for names of programs. @item tp @cindex @code{tp} (data type) index @findex tindex @findex tpindex (@code{@@tindex}) Data type index, for type names (such as structures defined in header files). @item vr @cindex @code{vr} (variable) index @findex vindex @findex vrindex (@code{@@vindex}) Variable index, for variable names (such as library global variables). @end table @noindent Not every manual needs all of these, and most manuals use only two or three at most. The present manual, for example, has two indices: a concept index and an @@-command index. (The latter is actually the function index but is called a command index in the chapter heading.) You are not required to use the predefined indices strictly for their canonical purposes. For example, suppose you wish to index some C preprocessor macros. You could put them in the function index along with actual functions, just by writing @code{@@findex} commands for them; then, when you print the ``Function Index'' as an unnumbered chapter, you could give it the title `Function and Macro Index' and all will be consistent for the reader. On the other hand, it is best not to stray too far from the meaning of the predefined indices. Otherwise, in the event that your text is combined with other text from other manuals, the index entries will not match up. Instead, define your own new index (@pxref{New Indices}). We recommend having a single index in the final document whenever possible, however many source indices you use, since then readers have only one place to look. Two or more source indices can be combined into one output index by using the @code{@@synindex} or @code{@@syncodeindex} commands (@pxref{Combining Indices}). Index entry commands based on the the two letter index names are also valid, for example @code{@@cpindex} can be used instead of @code{@@cindex}. @node Indexing Commands @nodedescription How to make an index entry. @section Defining the Entries of an Index @cindex Defining indexing entries @cindex Index entries @cindex Entries for an index @cindex Specifying index entries @cindex Creating index entries The data to make an index come from many individual indexing commands scattered throughout the Texinfo source file. Each command says to add one entry to a particular index; after formatting, the index will give the current page number or node name as the reference. An index entry consists of an indexing command at the beginning of a line followed, on the rest of the line, by the entry. For example, this section begins with the following five entries for the concept index: @example @@cindex Defining indexing entries @@cindex Index entries, defining @@cindex Entries for an index @@cindex Specifying index entries @@cindex Creating index entries @end example Each predefined index has its own indexing command---@code{@@cindex} for the concept index, @code{@@findex} for the function index, and so on, as listed in the previous section. Index entries should precede the visible material that is being indexed. For instance: @example @@cindex hello Hello, there! @end example @noindent Among other reasons, that way following indexing links (in whatever context) ends up before the material, where readers want to be, instead of after. In Info, an index is usually formatted as a menu. Try to avoid using a colon in index entries, as this may confuse some Info readers. @xref{Menu Parts} for more information about the structure of a menu entry. @c At the time of writing, it always works in standalone info, and a @c single colon not followed by a space works in Emacs. @cindex Index font types By default, entries for a concept index are printed in a roman font and entries for the other indices are printed in a typewriter font. You may change the way part of an entry is printed with the usual Texinfo commands, such as @code{@@file} for file names (@pxref{Marking Text}), and @code{@@r} for the normal roman font (@pxref{Fonts}). @findex sortas @cindex sort keys for index entries @cindex index sorting You may specify an explicit sort key for an index entry using @code{@@sortas} following either the index command or the text of the entry. For example: @samp{@@findex @@sortas@{\@} \ @@r@{(literal \ in @@code@{@@@@math@})} sorts the index entry this produces under backslash. @vindex txiindexbackslashignore @vindex txiindexhyphenignore @vindex txiindexlessthanignore @vindex txiindexatsignignore You may choose to ignore certain characters in index entries for the purposes of sorting. The characters that you can currently choose to ignore are @samp{\}, @samp{-}, @samp{<} and @samp{@@}, which are ignored by giving as an argument to the @code{@@set} command, respectively, @code{txiindexbackslashignore}, @code{txiindexhyphenignore}, @code{txiindexlessthanignore} and @code{txiindexatsignignore}. For example, specifying @samp{@@set txiindexbackslashignore} causes the @samp{\mathopsup} entry in the index for this manual to be sorted as if it were @samp{mathopsup}, so that it appears among the other entries beginning with `M'. This avoids the need to provide explicit sort keys for index entries containing these characters. When using these options, it is possible to get an index entry with an empty sort key. To avoid this, specify a @code{@@sortas} directive in the index entry. For example: @example @@set txiindexbackslashignore @@findex @@sortas@{\@} \ @end example @node Advanced Indexing @nodedescription Advanced indexing commands. @section Advanced Indexing Commands @cindex Indexing, advanced @cindex Advanced indexing Texinfo provides several further commands for indexing. @findex subentry First, you can create @dfn{multilevel} index entries, allowing you to group many related subtopics under the same higher-level topic. You do this by separating the parts of such an entry with the @code{@@subentry} command. Such commands might look like this: @example @@cindex Superhumans @@subentry villains @@cindex Superhumans @@subentry heroes @end example You may have up to three levels in an entry: @example @@cindex coffee makers @@subentry electric @@subentry pink @@cindex coffee makers @@subentry electric @@subentry blue @end example You can use the @code{@@sortas} command mentioned earlier with any or all of the three parts of an entry to cause them to sort differently than they would by default. @findex seeentry Second, you may provide an index entry that points to another, using the @code{@@seeentry} (``see entry'') command. For example: @example @@cindex Indexes @@seeentry@{Indices@} @end example Such an entry should be unique in your document; the idea is to redirect the reader to the other entry where they will find all the information they are looking for. @findex seealso Finally, you may provide a ``see also'' entry using the @code{@@seealso} command. These entries go along with regular entries, and are grouped together with them in the final printed index. For example: @example @@cindex Coffee @@cindex Coffee @@subentry With milk and sugar @@cindex Coffee @@subentry With doughnuts @@cindex Coffee @@subentry Decaffeinated @@cindex Coffee @@seealso@{Tea@} @end example When using all three of these advanced commands, @emph{do not} place a comma between the different parts of the index text. The @command{texindex} program, which sorts the index entries and generates the indexing formatting commands, takes care of placing commas in the correct places for you. Do not interrupt an index or @code{@@subentry} entry by @code{@@sortas} or advanced commands with braces; place the commands with braces at the beginning or at the end of the entry. These features are the most useful with printed documents, and when translating Texinfo to DocBook. @node Index Entries @nodedescription Choose different words for index entries. @section Making Index Entries @cindex Index entries, making @cindex Entries, making index @cindex Writing index entries @cindex Index entries, advice on writing @cindex Advice on writing entries @cindex Capitalization of index entries Concept index entries consist of text. The best way to write an index is to devise entries which are terse yet clear. If you can do this, the index usually looks better if the entries are written just as they would appear in the middle of a sentence, that is, capitalizing only proper names and acronyms that always call for uppercase letters. This is the case convention we use in most GNU manuals' indices. If you don't see how to make an entry terse yet clear, make it longer and clear---not terse and confusing. If many of the entries are several words long, the index may look better if you use a different convention: capitalize the first word of each entry. Whichever case convention you use, use it consistently. In any event, do not ever capitalize a case-sensitive name such as a C or Lisp function name or a shell command; that would be a spelling error. Entries in indices other than the concept index are symbol names in programming languages, or program names; these names are usually case-sensitive, so likewise use upper- and lowercase as required. @cindex Unique index entries It is a good idea to make index entries unique wherever feasible. That way, people using the printed output or online completion of index entries don't see undifferentiated lists. Consider this an opportunity to make otherwise-identical index entries be more specific, so readers can more easily find the exact place they are looking for. The advanced indexing features described in @ref{Advanced Indexing} can help with this, as well. When you are making index entries, it is good practice to think of the different ways people may look for something. Different people @emph{do not} think of the same words when they look something up. A helpful index will have items indexed under all the different words that people may use. For example, one reader may think it obvious that the two-letter names for indices should be listed under ``Indices, two-letter names'', since ``Indices'' are the general concept. But another reader may remember the specific concept of two-letter names and search for the entry listed as ``Two letter names for indices''. A good index will have both entries and will help both readers. Like typesetting, the construction of an index is a skilled art, the subtleties of which may not be appreciated until you need to do it yourself. @node Printing Indices & Menus @nodedescription How to print an index in hardcopy and generate index menus in Info. @section Printing Indices and Menus @cindex Printing an index @cindex Indices, printing and menus @cindex Generating menus with indices @cindex Menus generated with indices @findex printindex @code{@@printindex} takes one argument, a two-letter index abbreviation. You must include the @code{@@printindex} command at the place in the document where you want the index to appear. This does not happen automatically just because you use @code{@@cindex} or other index-entry generating commands in the Texinfo file; those just cause the raw data for the index to be accumulated. You should precede the @code{@@printindex} command with a suitable section or chapter command (usually @code{@@appendix} or @code{@@unnumbered}) to supply the chapter heading and put the index into the table of contents. Precede the chapter heading with an @code{@@node} line as usual. For example: @example @group @@node Variable Index @@unnumbered Variable Index @@printindex vr @end group @group @@node Concept Index @@unnumbered Concept Index @@printindex cp @end group @end example The text @samp{Index} needs to appear in the name of the node containing the index for the index to be found by Info readers. If you have more than one index, we recommend placing the concept index last. Other details of index output in output formats: @itemize @item As part of the process of creating a printed manual with @TeX{}, you run a program called @command{texindex} (@pxref{Hardcopy with @TeX{}}) to sort the raw data to produce a sorted index file. The sorted index file is what is actually used to print the index. @code{@@printindex} reads the corresponding sorted index file and produces a traditional two-column index, with index terms and page numbers. @item In Info output, @code{@@printindex} produces a special menu containing the line number of the entry, relative to the start of the node. Info readers can use this to go to the exact line of an entry, not just the containing node. (Older Info readers will just go to the node.) Here's an example: @example * First index entry: Top. (line 7) @end example @item In plain text output, @code{@@printindex} formatting is usually similar to a menu in Info, showing the line number of each entry relative to the start of the file. @item In HTML output, @code{@@printindex} produces links to the index entries. @item In DocBook and @LaTeX{} output, it simply records the index to be printed. @end itemize @node Combining Indices @nodedescription How to combine indices. @section Combining Indices @cindex Combining indices @cindex Indices, combining them Sometimes you will want to combine two disparate indices such as functions and concepts, perhaps because you have few enough entries that a separate index would look silly. You could put functions into the concept index by writing @code{@@cindex} commands for them instead of @code{@@findex} commands, and produce a consistent manual by printing the concept index with the title `Function and Concept Index' and not printing the `Function Index' at all; but this is not a robust procedure. It works only if your document is never included as part of another document that is designed to have a separate function index; if your document were to be included with such a document, the functions from your document and those from the other would not end up together. Also, to make your function names appear in the right font in the concept index, you would need to enclose every one of them between the braces of @code{@@code}. @node @code{@@syncodeindex} @nodedescription How to merge two indices, using @code{@@code} font for the merged-from index. @subsection @code{@@syncodeindex}: Combining Indices Using @code{@@code} @anchor{syncodeindex}@c old name @findex syncodeindex When you want to combine functions and concepts into one index, you should index the functions with @code{@@findex} and index the concepts with @code{@@cindex}, and use the @code{@@syncodeindex} command to redirect the function index entries into the concept index. The @code{@@syncodeindex} command takes two arguments; they are the name of the index to redirect, and the name of the index to redirect it to. The template looks like this: @example @@syncodeindex @var{from} @var{to} @end example @cindex Predefined names for indices @cindex Two letter names for indices @cindex Indices, two letter names @cindex Names for indices For this purpose, the indices are given two-letter names: @table @samp @item cp Concept index @item fn Function index @item ky Key index @item pg Program index @item tp Data type index @item vr Variable index @end table Write a @code{@@syncodeindex} command before or shortly after the end-of-header line at the beginning of a Texinfo file. For example, to merge a function index with a concept index, write the following: @example @@syncodeindex fn cp @end example @noindent This causes all entries designated for the function index to merge in with the concept index instead. To merge both a variable index and a function index into a concept index, write the following: @example @group @@syncodeindex vr cp @@syncodeindex fn cp @end group @end example @cindex Fonts for indices The @code{@@syncodeindex} command puts all the entries from the `from' index (the redirected index) into the @code{@@code} font, overriding whatever default font is used by the index to which the entries are now directed. This way, if you direct function names from a function index into a concept index, all the function names are printed in the @code{@@code} font as you would expect. @node @code{@@synindex} @nodedescription How to merge two indices, using the roman font for the merged-from index. @subsection @code{@@synindex}: Combining Indices @anchor{synindex}@c old name @findex synindex The @code{@@synindex} command is nearly the same as the @code{@@syncodeindex} command, except that it does not put the `from' index entries into the @code{@@code} font; rather it puts them in the roman font. Thus, you use @code{@@synindex} when you merge a concept index into a function index. @xref{Printing Indices & Menus}, for information about printing an index at the end of a book or creating an index menu in an Info file. @node New Indices @nodedescription How to define your own indices. @section Defining New Indices @cindex Defining new indices @cindex Indices, defining new @cindex New index defining @findex defindex @findex defcodeindex In addition to the predefined indices (@pxref{Predefined Indices}), you may use the @code{@@defindex} and @code{@@defcodeindex} commands to define new indices. These commands create new indexing @@-commands with which you mark index entries. The @code{@@defindex} command is used like this: @example @@defindex @var{name} @end example New index names are usually two-letter words, such as @samp{au}. For example: @example @@defindex au @end example This defines a new index, called the @samp{au} index. At the same time, it creates a new indexing command, @code{@@auindex}, that you can use to make index entries. Use this new indexing command just as you would use a predefined indexing command. For example, here is a section heading followed by a concept index entry and two @samp{au} index entries. @example @@section Cognitive Semantics @@cindex kinesthetic image schemas @@auindex Johnson, Mark @@auindex Lakoff, George @end example @noindent (Evidently, @samp{au} serves here as an abbreviation for ``author''.) Texinfo constructs the new indexing command by concatenating the name of the index with @samp{index}; thus, defining an @samp{xy} index leads to the automatic creation of an @code{@@xyindex} command. Use the @code{@@printindex} command to print the index, as you do with the predefined indices. For example: @example @group @@node Author Index @@unnumbered Author Index @@printindex au @end group @end example The @code{@@defcodeindex} command is like the @code{@@defindex} command, except that, in the printed output, it prints entries in an @code{@@code} font by default instead of in a roman font. You should define new indices before the end-of-header line of a Texinfo file, and (of course) before any @code{@@synindex} or @code{@@syncodeindex} commands (@pxref{Texinfo File Header}). As mentioned earlier (@pxref{Predefined Indices}), we recommend having a single index in the final document whenever possible (no matter how many source indices you use), since then readers have only one place to look. When creating an index, @TeX{} creates a file whose extension is the name of the index (@pxref{Names of index files}). Therefore you should avoid using index names that collide with extensions used for other purposes, such as @samp{.aux} or @samp{.xml}. @command{texi2any} already reports an error if a new index conflicts well-known extension name. @node Insertions @nodedescription Inserting @@-signs, braces, etc. @chapter Special Insertions @cindex Inserting special characters and symbols @cindex Special insertions Texinfo provides several commands for inserting characters that have special meaning in Texinfo, such as braces, and for other graphic elements that do not correspond to simple characters you can type. @node Special Characters @nodedescription Inserting @@ @{@} , \ # & @section Special Characters: Inserting @@ @{@} , \ # & @anchor{Braces Atsign}@c previous names for this node @anchor{Atsign Braces Comma} @cindex Special characters, inserting @cindex Commands to insert special characters @samp{@@} and curly braces are the basic special characters in Texinfo. To insert these characters so they appear in text, you must put an @samp{@@} in front of these characters to prevent Texinfo from misinterpreting them. Alphabetic commands are also provided. The other characters (comma, backslash, hash, ampersand) are special only in restricted contexts, as explained in the respective sections. @node Inserting an Atsign @nodedescription @code{@@@@}, @code{@@atchar@{@}}. @subsection Inserting `@@' with @code{@@@@} and @code{@@atchar@{@}} @cindex At sign, inserting @cindex Inserting @@ @r{(literal @samp{@@})} @findex @sortas{@@} @@ @r{(literal @samp{@@})} @ifset commandlookup @findex @sortas{@@} @@ @end ifset @findex atchar @code{@@@@} produces a single @samp{@@} character in the output. Do not put braces after an @code{@@@@} command. @code{@@atchar@{@}} also produces a single @samp{@@} character in the output. It does need following braces, as usual for alphabetic commands. In inline conditionals (@pxref{Inline Conditionals}), it can be necessary to avoid using the literal @samp{@@} character in the source (and may be clearer in other contexts). @node Inserting Braces @nodedescription @code{@@@{ @@@}}, @code{@@l rbracechar@{@}}. @subsection Inserting `@{ `@}' with @code{@@@{ @@@}} and @code{@@l rbracechar@{@}} @findex @{ @r{(literal @samp{@{})} @findex @} @r{(literal @samp{@}})} @ifset commandlookup @findex @{ @findex @} @end ifset @findex lbracechar @findex rbracechar @cindex Braces, inserting @code{@@@{} produces a single @samp{@{} in the output, and @code{@@@}} produces a single @samp{@}}. Do not put braces after either an @code{@@@{} or an @code{@@@}} command. @code{@@lbracechar@{@}} and @code{@@rbracechar@{@}} also produce single @samp{@{} and @samp{@}} characters in the output. They do need following braces, as usual for alphabetic commands. In inline conditionals (@pxref{Inline Conditionals}), it can be necessary to avoid using literal brace characters in the source (and may be clearer in other contexts). @node Inserting a Comma @nodedescription , and @code{@@comma@{@}}. @subsection Inserting `,' with @code{@@comma@{@}} @findex comma @cindex Comma, inserting Ordinarily, a comma `,' is a normal character that can be simply typed in your input where you need it. However, Texinfo uses the comma as a special character only in one context: to separate arguments to those Texinfo commands, such as @code{@@node} (@pxref{Node Line Requirements}), @code{@@acronym} (@pxref{@code{@@acronym}}) and @code{@@xref} (@pxref{Cross References}), as well as user-defined macros (@pxref{Defining Macros}), which take more than one argument. Since a comma character would confuse Texinfo's parsing for these commands, you must use the command @samp{@@comma@{@}} instead if you want to pass an actual comma. Here are some examples: @example @@acronym@{ABC, A Bizarre @@comma@{@}@} @@xref@{Comma,, The @@comma@{@} symbol@} @@mymac@{One argument@@comma@{@} containing a comma@} @end example Although @samp{@@comma@{@}} can be used nearly anywhere, there is no need for it anywhere except in this unusual case. (Incidentally, the name @samp{@@comma} lacks the @samp{char} suffix used in its companion commands only for historical reasons. It didn't seem important enough to define a synonym.) @node Inserting a Backslash @nodedescription \ and @code{@@backslashchar@{@}}. @subsection Inserting `\' with @code{@@backslashchar@{@}} @findex backslashchar @cindex Backslash, inserting Ordinarily, a backslash `\' is a normal character in Texinfo that can be simply typed in your input where you need it. The result is to typeset the backslash from the typewriter font. However, Texinfo uses the backslash as a special character in one restricted context: to delimit formal arguments in the bodies of user-defined macros (@pxref{Defining Macros}). Due to the vagaries of macro argument parsing, it is more reliable to pass an alphabetic command that produces a backslash instead of using a literal \. Hence @code{@@backslashchar@{@}}. Here is an example macro call: @example @@mymac@{One argument@@backslashchar@{@} with a backslash@} @end example @findex \backslash @findex @sortas{\} \ @r{(literal @samp{\} in math)} @ifset commandlookup @findex @sortas{\} \ @end ifset Texinfo documents may also use \ as a command character inside @code{@@math} (@pxref{Inserting Math}). In this case, @code{@@\} or @code{\backslash} produce a ``math'' backslash (from the math symbol font), while @code{@@backslashchar@{@}} produces a typewriter backslash as usual. Although @samp{@@backslashchar@{@}} can be used nearly anywhere, there is no need for it except in these unusual cases. @node Inserting a Hashsign @nodedescription # and @code{@@hashchar@{@}}. @subsection Inserting `#' with @code{@@hashchar@{@}} @findex hashchar @cindex Inserting # @cindex Hash sign, inserting Ordinarily, a hash `#' is a normal character in Texinfo that can be simply typed in your input where you need it. The result is to typeset the hash character from the current font. @cindex Number sign, inserting @cindex Octotherp, inserting @cindex Sharp sign (not), inserting This character has many other names, varying by locale, such as ``number sign'', ``pound'', and ``octothorp''. It is also sometimes called ``sharp'' or ``sharp sign'' since it vaguely resembles the musical symbol by that name. In situations where Texinfo is used, ``hash'' is the most common in our experience. However, Texinfo uses the hash character as a special character in one restricted context: to introduce the so-called @code{#line} directive and variants (@pxref{External Macro Processors}). So, in order to typeset an actual hash character in such a place (for example, in a program that needs documentation about @code{#line}), it's necessary to use @code{@@hashchar@{@}} or some other construct. Here's an example: @example @@hashchar@{@} 10 "example.c" @end example Although @samp{@@hashchar@{@}} can be used nearly anywhere, there is no need for it anywhere except this unusual case. @node Inserting an Ampersand @nodedescription & and @code{@@ampchar@{@}}. @subsection Inserting `&' with @code{@@&} and @code{@@ampchar@{@}} @findex ampchar @findex & @r{(literal @samp{&})} @ifset commandlookup @findex & @end ifset @cindex Inserting & @cindex Ampersand, inserting Ordinarily, an ampersand `&' is a normal character in Texinfo that can be simply typed in your input where you need it. The result is to typeset the ampersand character. However, the ampersand character is treated specially in just one restricted context. In the argument to a definition command (@pxref{Definition Commands}), an ampersand followed by a series of letters may be typeset specially when processing with @TeX{} @footnote{This syntax is used for Emacs Lisp keywords. @xref{A Sample Function Description,,, elisp, GNU Emacs Lisp Reference Manual}.} (@pxref{Def Cmd Conventions}). For example: @example @@defun foo integer1 &optional integer2 &rest integers @@code@{foo@} described here. @@end defun @end example @noindent may have @samp{&optional} and @samp{&rest} formatted in bold, even without any @@-command involved. So, in order to typeset an ampersand in such a context, it's necessary to use @code{@@&} or some other construct. Here's an example of a C++ function taking a reference as a parameter: @example @@deftypefn Function int foo (const std::vector<int>@@& @@var@{bar@}) Documentation of @@code@{foo@}. @@end deftypefn @end example @noindent This gives the output @deftypefn Function int foo (const std::vector<int>@& @var{bar}) Documentation of @code{foo}. @end deftypefn Although @samp{@@&} and @samp{@@ampchar@{@}} can be used nearly anywhere, there is no need for them anywhere except this unusual case. @node Inserting Quote Characters @nodedescription Inserting left and right quotes, in code. @section Inserting Quote Characters @cindex Inserting quote characters @cindex Quote characters, inserting As explained in the early section on general Texinfo input conventions (@pxref{Conventions}), Texinfo source files use the ASCII character @code{`} (96 decimal) to produce a left quote (`), and ASCII @code{'} (39 decimal) to produce a right quote ('). Doubling these input characters (@code{``} and @code{''}) produces double quotes (`` and ''). These are the conventions used by @TeX{}. In examples of computer code, however, @code{`} and @code{'} produce typical renderings for these ASCII characters: the backtick character (standalone grave accent) and undirected single quote respectively. In the past, directed glyphs @iftex @clear txicodequoteundirected @clear txicodequotebacktick (@code{`} and @code{'}) @set txicodequoteundirected @set txicodequotebacktick @end iftex were used by default in @TeX{} output. Texinfo provides these commands to choose between these alternate renderings: @table @code @findex codequoteundirected @cindex undirected single quote @item @@codequoteundirected @var{on-off} Set to @samp{off} to output the @code{'} character in code environments as the right curly single quote. @findex codequotebacktick @cindex Backtick @cindex Grave accent @subentry standalone @item @@codequotebacktick @var{on-off} Set to @samp{off} to output the @code{`} character in code environments as the left curly single quote. @end table If you want these settings for only part of the document, @code{@@codequote... on} will restore the normal behavior, as in @code{@@codequoteundirected on}. These settings affect @code{@@code}, @code{@@example}, @code{@@kbd}, @code{@@samp}, @code{@@verb}, and @code{@@verbatim}. @xref{Useful Highlighting}. Unfortunately, some document viewers will mangle the directed quote characters when copying and pasting. (The free PDF reader @command{xpdf} works fine, but other PDF readers, both free and nonfree, have problems.) @vindex txicodequoteundirected @vindex txicodequotebacktick This feature can also be controlled by using @code{@@set} and @code{@@clear} on the corresponding variables @code{txicodequoteundirected} and @code{txicodequotebacktick}. @node Inserting Space @nodedescription Inserting the right amount of whitespace. @section Inserting Space @cindex Inserting space @cindex Spacing, inserting The following sections describe commands that control spacing of various kinds within and after sentences. @node Multiple Spaces @nodedescription Inserting multiple spaces. @subsection Multiple Spaces @cindex Multiple spaces @cindex Whitespace, inserting @cindex Space, inserting horizontal @findex <space> @findex <tab> @findex <newline> Ordinarily, multiple whitespace characters (space, tab, and newline) are collapsed into a single space. Occasionally, you may want to produce several consecutive spaces, either for purposes of example (e.g., what your program does with multiple spaces as input), or merely for purposes of appearance in headings or lists. Texinfo supports three commands: @code{@@@kbd{SPACE}}, @code{@@@kbd{TAB}}, and @code{@@@kbd{NL}}, all of which insert a single space into the output. (Here, @code{@@@kbd{SPACE}} represents an @samp{@@} character followed by a space, i.e., @samp{@@ }, @kbd{TAB} represents an actual tab character, and @code{@@@kbd{NL}} represents an @samp{@@} character and end-of-line, i.e., when @samp{@@} is the last character on a line.) For example, @example Spacey@@ @@ @@ @@ example. @end example @noindent produces @example Spacey@ @ @ @ example. @end example Do not follow any of these commands with braces. To produce a non-breakable space, see @ref{@code{@@tie}}. @node Not Ending a Sentence @nodedescription Sometimes a .@ doesn't end a sentence. @subsection Not Ending a Sentence @cindex Not ending a sentence @cindex Sentence non-ending punctuation @cindex Periods, inserting @cindex Spacing, in the middle of sentences When a period, exclamation point or question mark is at the end of a sentence, slightly more space is inserted after it in a typeset manual. @findex : @r{(suppress end-of-sentence space)} @ifset commandlookup @findex : @end ifset Usually, Texinfo can determine automatically when a period ends a sentence. However, special commands are needed in some circumstances. Use the @code{@@:} command after a period, question mark, exclamation mark or colon that should not be followed by extra space. This is necessary in the following situations: @enumerate @item After a period that ends a lowercase abbreviation which is not at the end of a sentence. @item When a parenthetical remark in the middle of a sentence (like this one!)@: ends with a period, exclamation point or question mark, @code{@@:} should be used after the right parenthesis. Similarly for right brackets and right quotes (both single and double). @end enumerate For example: @example @samp{foo vs.@@: bar (or?)@@: baz}, @end example @noindent The first line below shows the output, and for comparison, the second line shows the spacing when the @samp{@@:} commands were not used. @quotation foo vs.@: bar (or?)@: baz@* foo vs. bar (or?) baz @end quotation @iftex If you look carefully, you will see a bit of extraneous space after the @samp{vs.}@: and @samp{(or?)}@:. @end iftex It may help you to remember what @code{@@:} does by imagining that it stands for an invisible lower-case character that stops a word ending in a period. A few Texinfo commands force normal interword spacing, so that you don't have to insert @code{@@:} where you otherwise would. These are the code-like highlighting commands, @code{@@var}, @code{@@abbr}, and @code{@@acronym} (@pxref{Useful Highlighting}). For example, in @samp{@@code@{foo. bar@}} the period is not considered to be the end of a sentence, and no extra space is inserted. @code{@@:} has no effect on the HTML or DocBook output. @node Ending a Sentence @nodedescription Sometimes it does. @subsection Ending a Sentence @cindex Ending a Sentence @cindex Sentence ending punctuation @findex . @r{(end of sentence)} @findex ! @r{(end of sentence)} @findex ? @r{(end of sentence)} @ifset commandlookup @findex . @findex ! @findex ? @end ifset @cindex Spacing, at ends of sentences As mentioned above, Texinfo normally inserts additional space after the end of a sentence. It uses the same heuristic for this as @TeX{}: a sentence ends with a period, exclamation point, or question mark, either preceded or followed by optional closing punctuation, and then whitespace, and @emph{not} preceded by a capital letter. Use @code{@@.}@: instead of a period, @code{@@!}@: instead of an exclamation point, and @code{@@?}@: instead of a question mark at the end of a sentence that does end with a capital letter. Do not put braces after any of these commands. For example: @example Give it to M.I.B. and to M.E.W@@. Also, give it to R.J.C@@. Give it to M.I.B. and to M.E.W. Also, give it to R.J.C. @end example @noindent The output follows. In printed output and Info, you can see the desired extra whitespace after the @samp{W} in the first line. @quotation Give it to M.I.B. and to M.E.W@. Also, give it to R.J.C@.@* Give it to M.I.B. and to M.E.W. Also, give it to R.J.C. @end quotation In other output formats, @code{@@.}@: is equivalent to a simple @samp{.}; likewise for @code{@@!}@: and @code{@@?}@:. @cindex Closing punctuation, and sentence ending The ``closing punctuation'' mentioned above is defined as a right parenthesis (@samp{)}, right bracket (@samp{]}), or right quote, either single or double (@samp{'} and @samp{''}; the many possible additional Unicode right quotes are not included). These characters can be thought of as invisible with respect to whether a given period ends a sentence. (This is the same rule as @TeX{}.) For instance, the periods in @samp{foo.) Bar} and @samp{foo.'' Bar} do end sentences. The meanings of @code{@@:} and @code{@@.}, etc.@: in Texinfo are designed to work well with the Emacs sentence motion commands (@pxref{Sentences,,, emacs, The GNU Emacs Manual}). It may help to imagine that the @samp{@@} in @samp{@@.}, etc., is an invisible lower-case letter `a' which makes an upper-case letter before it immaterial for the purposes of deciding whether the period ends the sentence. A few Texinfo commands are not considered as being an abbreviation, even though they may end with a capital letter when expanded, so that you don't have to insert @code{@@.} and companions. Notably, this is the case for code-like highlighting commands, @code{@@var} arguments ending with a capital letter, @code{@@LaTeX}, and @code{@@TeX}. For example, that sentence ended with @samp{... @@code@{@@@@TeX@}.}; @code{@@.} was not needed. Similarly, in @code{... @@var@{VARNAME@}. Text} the period after @var{VARNAME} ends the sentence; there is no need to use @code{@@.}. @node @code{@@frenchspacing} @nodedescription Specifying end-of-sentence spacing. @subsection @code{@@frenchspacing} @var{val}: Control Sentence Spacing @anchor{frenchspacing}@c old name @findex frenchspacing @cindex French spacing @cindex Sentences, spacing after @cindex Space, after sentences In American typography, it is traditional and correct to put extra space at the end of a sentence. This is the default in Texinfo (implemented in Info and printed output, not in other output formats). In French typography (and others), this extra space is wrong; all spaces are uniform. Therefore Texinfo provides the @code{@@frenchspacing} command to control the spacing after punctuation. It reads the rest of the line as its argument, which must be the single word @samp{on} or @samp{off} (always these words, regardless of the language of the document). Here is an example: @example @@frenchspacing on This is text. Two sentences. Three sentences. French spacing. @@frenchspacing off This is text. Two sentences. Three sentences. Non-French spacing. @end example @noindent produces: @frenchspacing on This is text. Two sentences. Three sentences. French spacing. @frenchspacing off This is text. Two sentences. Three sentences. Non-French spacing. @code{@@frenchspacing} also affects the output after @code{@@.}, @code{@@!}, and @code{@@?} (@pxref{Ending a Sentence}). @code{@@frenchspacing} has no effect on the HTML or DocBook output. @node @code{@@dmn} @nodedescription Formatting a dimension. @subsection @code{@@dmn}@{@var{dimension}@}: Format a Dimension @anchor{dmn}@c old name @cindex Thin space between number, dimension @cindex Dimension formatting @cindex Format a dimension @findex dmn You can use the @code{@@dmn} command to format a dimension with just enough space for proper typesetting inserted in printed output. In other output formats, the formatting commands insert no space at all. To use the @code{@@dmn} command, write the number and then follow it immediately, with no intervening space, by @code{@@dmn}, and then by the dimension within braces. For example, @example A4 paper is 8.27@@dmn@{in@} wide. @end example @noindent produces @quotation A4 paper is 8.27@dmn{in} wide. @end quotation Not everyone uses this style. Some people prefer `8.27@tie{}in.'@: or `8.27@tie{}inches'. In these cases, however, you need to use @code{@@tie} (@pxref{@code{@@tie}}) or @code{@@w} (@pxref{@code{@@w}}) so that no line break can occur between the number and the dimension. Also, if you write a period after an abbreviation within a sentence (as with the `in.'@: above), you should write @samp{@@:} after the period to avoid inserting extra whitespace in printed output, as shown here. @xref{Not Ending a Sentence}. @node Inserting Accents @nodedescription Inserting accents and special characters. @section Inserting Accents @cindex Inserting accents @cindex Accents, inserting @cindex Floating accents, inserting Here is a table with the commands Texinfo provides for inserting floating accents. They all need an argument, the character to accent, which can either be given in braces as usual (@code{@@'@{e@}}), or, as a special case, the braces can be omitted, in which case the argument is the next character (@code{@@'e}). This is to make the source as convenient as possible to type and read, since accented characters are very common in some languages. If the command is alphabetic, such as @code{@@dotaccent}, then there must be a space between the command name and argument if braces are not used. If the command is non-alphabetic, such as @code{@@'}, then there must @emph{not} be a space; the argument is the very next character. Exception: the argument to @code{@@tieaccent} must be enclosed in braces (since it is two characters instead of one). In Info and plain text output, accent constructs are output as the true accented characters if the document encoding supports the required characters, unless the option @option{--disable-encoding} is given to @command{texi2any} (@pxref{@code{@@documentencoding}}). ASCII transliterations are used if the encoded characters are not output. @findex " @r{(umlaut accent)} @cindex Umlaut accent @findex ' @r{(acute accent)} @cindex Acute accent @findex = @r{(macron accent)} @cindex Macron accent @findex ^ @r{(circumflex accent)} @cindex Circumflex accent @findex ` @r{(grave accent)} @cindex Grave accent @findex ~ @r{(tilde accent)} @cindex Tilde accent @findex , @r{(cedilla accent)} @cindex Cedilla accent @findex dotaccent @cindex Dot accent @findex H @r{(Hungarian umlaut accent)} @cindex Hungarian umlaut accent @findex ogonek @cindex Ogonek diacritic @findex ringaccent @cindex Ring accent @findex tieaccent @cindex Tie-after accent @findex u @r{(breve accent)} @cindex Breve accent @findex ubaraccent @cindex Underbar accent @findex udotaccent @cindex Underdot accent @findex v @r{(caron)} @cindex Hacek accent @cindex Check accent @cindex Caron @ifset commandlookup @findex " @findex ' @findex = @findex ^ @findex ` @findex ~ @findex , @findex H @findex u @findex v @end ifset @multitable {@t{@@questiondown@{@}}} {Output} {caron/hacek/check accent} @headitem Command @tab Output @tab What @item @t{@@"o} @tab @"o @tab umlaut accent @item @t{@@'o} @tab @'o @tab acute accent @item @t{@@,@{c@}} @tab @,{c} @tab cedilla accent @item @t{@@=o} @tab @=o @tab macron/overbar accent @item @t{@@^o} @tab @^o @tab circumflex accent @item @t{@@`o} @tab @`o @tab grave accent @item @t{@@~o} @tab @~o @tab tilde accent @item @t{@@dotaccent@{o@}} @tab @dotaccent{o} @tab overdot accent @item @t{@@H@{o@}} @tab @H{o} @tab long Hungarian umlaut @item @t{@@ogonek@{a@}} @tab @ogonek{a} @tab ogonek @item @t{@@ringaccent@{o@}} @tab @ringaccent{o} @tab ring accent @item @t{@@tieaccent@{oo@}} @tab @tieaccent{oo} @tab tie-after accent @item @t{@@u@{o@}} @tab @u{o} @tab breve accent @item @t{@@ubaraccent@{o@}} @tab @ubaraccent{o} @tab underbar accent @item @t{@@udotaccent@{o@}} @tab @udotaccent{o} @tab underdot accent @item @t{@@v@{o@}} @tab @v{o} @tab caron/hacek/check accent @end multitable This table lists the Texinfo commands for inserting other characters commonly used in languages other than English. @findex questiondown @cindex @questiondown{} @findex exclamdown @cindex @exclamdown{} @findex aa @cindex @aa{} @findex AA @cindex @AA{} @findex ae @cindex @ae{} @findex AE @cindex @AE{} @cindex Icelandic @cindex Eth @findex dh @cindex @dh{} @findex DH @cindex @DH{} @findex dotless @cindex @dotless{i} (dotless i) @cindex @dotless{j} (dotless j) @cindex Dotless i, j @findex l @cindex @l{} @findex L @cindex @L{} @findex o @cindex @o{} @findex O @cindex @O{} @findex oe @cindex @oe{} @findex OE @cindex @OE{} @cindex Romance ordinals @cindex Ordinals, Romance @cindex Feminine ordinal @findex ordf @cindex @ordf{} @cindex Masculine ordinal @findex ordm @cindex @ordm{} @findex ss @cindex @ss{} @cindex Es-zet @cindex Sharp S @cindex German S @cindex Thorn @findex th @cindex @th{} @findex TH @cindex @TH{} @multitable {@t{@@questiondown@{@}}} {oe OE} {es-zet or sharp S} @item @t{@@exclamdown@{@}} @tab @exclamdown{} @tab upside-down ! @item @t{@@questiondown@{@}} @tab @questiondown{} @tab upside-down ? @item @t{@@aa@{@} @@AA@{@}} @tab @aa{} @AA{} @tab a,A with circle @item @t{@@ae@{@} @@AE@{@}} @tab @ae{} @AE{} @tab ae,AE ligatures @item @t{@@dh@{@} @@DH@{@}} @tab @dh{} @DH{} @tab Icelandic eth @item @t{@@dotless@{i@}} @tab @dotless{i} @tab dotless i @item @t{@@dotless@{j@}} @tab @dotless{j} @tab dotless j @item @t{@@l@{@} @@L@{@}} @tab @l{} @L{} @tab suppressed-L,l @item @t{@@o@{@} @@O@{@}} @tab @o{} @O{} @tab O,o with slash @item @t{@@oe@{@} @@OE@{@}} @tab @oe{} @OE{} @tab oe,OE ligatures @item @t{@@ordf@{@} @@ordm@{@}} @tab @ordf{} @ordm{} @tab Spanish ordinals @item @t{@@ss@{@}} @tab @ss{} @tab es-zet or sharp S @item @t{@@th@{@} @@TH@{@}} @tab @th{} @TH{} @tab Icelandic thorn @end multitable @node Inserting Quotation Marks @nodedescription Inserting quotation marks. @section Inserting Quotation Marks @cindex Inserting quotation marks @cindex Quotation marks, inserting @cindex Quotation characters (`'), in source Use doubled single-quote characters to begin and end quotations: @w{@t{`@w{}`@dots{}'@w{}'}}. Two single quotes are converted to left- and right-hand doubled quotation marks, ``like this''. You may occasionally need to produce two consecutive single quotes; for example, in documenting a computer language such as Maxima where @t{'@w{}'} is a valid command. You can do this with the input @t{'@@w@{@}'}; the empty @code{@@w} command stops the combination into the double-quote characters. @cindex Unicode quotation characters @cindex Grave accent @subentry vs. left quote The left quote character (@t{`}, ASCII code 96) used in Texinfo is a grave accent in ANSI and ISO character set standards. We use it as a quote character because that is how @TeX{} is set up, by default. Texinfo supports several other quotation marks used in languages other than English. Below is a table with the commands Texinfo provides for inserting quotation marks. @cindex Single quotation marks @cindex Double quotation marks @cindex Left quotation marks @cindex Right quotation marks @findex quotedblleft @cindex @code{`@w{}`} @findex quoteleft @cindex @code{`} @cindex " (undirected double quote character) @findex quotedblright @cindex '@w{}' @findex quoteright @cindex ' @cindex Double low-9 quotation mark @cindex Single low-9 quotation mark @findex quotedblbase @cindex @quotedblbase{} (double low-9 quotation mark) @findex quotesinglbase @cindex @quotesinglbase{} (single low-9 quotation mark) @cindex Angle quotation marks @cindex Guillemets @cindex Guillemots @cindex French quotation marks @cindex Quotation marks, French @cindex German quotation marks @cindex Quotation marks, German @cindex Double guillemets @cindex Single guillemets @cindex Double angle quotation marks @cindex Single angle quotation marks @cindex Left-pointing angle quotation marks @cindex Right-pointing angle quotation marks @cindex Double left-pointing angle quotation mark @cindex Double right-pointing angle quotation mark @cindex Single left-pointing angle quotation mark @cindex Single right-pointing angle quotation mark @findex guillemetleft @findex guillemotleft @cindex @sortas{<<} @guillemetleft{} @findex guillemetright @findex guillemotright @cindex @guillemetright{} @findex guilsinglleft @cindex @sortas{<} @guilsinglleft{} @findex guilsinglright @cindex @guilsinglright{} @c The third column doesn't have the full text in the prototype so that @c the Info output fits within 72 columns. @multitable {@t{@@quotedblright@{@} '@w{}'}} {Glyph} {Right-pointing double angle quotation} @headitem Command @tab Glyph @tab Unicode name (point) @item @verb{.@quotedblleft{} ``.} @tab @quotedblleft{} @tab Left double quotation mark (U+201C) @item @verb{.@quotedblright{} ''.} @tab @quotedblright{} @tab Right double quotation mark (U+201D) @item @verb{.@quoteleft{} `.} @tab @quoteleft{} @tab Left single quotation mark (U+2018) @item @verb{.@quoteright{} '.} @tab @quoteright{} @tab Right single quotation mark (U+2019) @item @t{@@quotedblbase@{@}} @tab @quotedblbase{} @tab Double low-9 quotation mark (U+201E) @item @t{@@quotesinglbase@{@}} @tab @quotesinglbase{} @tab Single low-9 quotation mark (U+201A) @item @t{@@guillemetleft@{@}} @tab @guillemetleft{} @tab Left-pointing double angle quotation mark (U+00AB) @item @t{@@guillemetright@{@}} @tab @guillemetright{} @tab Right-pointing double angle quotation mark (U+00BB) @item @t{@@guilsinglleft@{@}} @tab @guilsinglleft{} @tab Single left-pointing angle quotation mark (U+2039) @item @t{@@guilsinglright@{@}} @tab @guilsinglright{} @tab Single right-pointing angle quotation mark (U+203A) @end multitable @cindex Auk, bird species For the double angle quotation marks, Adobe and @LaTeX{} glyph names are also supported: @code{@@guillemotleft} and @code{@@guillemotright}. These names are incorrect; a ``guillemot'' is a bird species (a type of auk). @cindex European Computer Modern fonts @cindex EC fonts The standard @TeX{} fonts support the usual quotation marks used in English (the ones produced with single and doubled ASCII single quotes). For the other quotation marks, @TeX{} uses European Computer Modern (EC) fonts (@file{ecrm1000} and other variants). These fonts are freely available, of course; you can download them from @url{http://ctan.org/pkg/ec}, among other places. @cindex CM-Super fonts The free EC fonts are bitmap fonts created with Metafont. Especially for on-line viewing, Type@tie{}1 (vector) versions of the fonts are preferable; these are available in the CM-Super font package (@url{http://ctan.org/pkg/cm-super}). Both distributions include installation instructions. Traditions for quotation mark usage vary to a great extent between languages (@url{https://en.wikipedia.org/wiki/Quotation_mark}). Texinfo does not provide commands or configurations for typesetting quotation marks according to the numerous traditions. Therefore, you have to choose the commands appropriate for the language of your manual. Sometimes aliases (@pxref{@code{@@alias}}) can simplify the usage and make the source code more readable. For example, in German, @code{@@quotedblbase} is used for the left double quote, and the right double quote is the glyph produced by @code{@@quotedblleft}, which is counterintuitive. Thus, in this case the following aliases would be convenient: @example @@alias lgqq = quotedblbase @@alias rgqq = quotedblleft @end example @node Inserting Subscripts and Superscripts @nodedescription Inserting sub/superscripts. @section @code{@@sub} and @code{@@sup}: Inserting Subscripts and Superscripts @findex sub @findex sup @cindex Subscripts and superscripts, text You can insert subscripts and superscripts with the @code{@@sub} and @code{@@sup} commands. For example: @example here@@sub@{below@}@@sup@{above@} @end example @noindent produces: @display here@sub{below}@sup{above} @end display In Info and plain text, @code{@@sub@{@var{text}@}} is currently output as @samp{_@{@var{text}@}} and @code{@@sup@{@var{text}@}} as @samp{^@{@var{text}@}}, including the literal braces (to mark the beginning and end of the ``script'' text to the reader). When the output format (and display program) permit (printed output, HTML), the superscript is set above the subscript when both commands are given consecutively. For subscripts and superscripts in mathematical expressions, it is better to use @TeX{}'s @samp{_} and @samp{^} characters. See the next section. @node Inserting Math @nodedescription Formatting mathematical expressions. @section @code{@@math} and @code{@@displaymath}: Formatting Mathematics @anchor{math}@c old name @findex math @cindex Mathematical expressions, inserting @cindex Formulas, mathematical You can write a mathematical expression, equation or formula using the @code{@@math} command. Write the @TeX{} math notation between braces, like this: @example @@math@{\partial_\alpha \partial^\alpha A^\beta = \mu_0 J^\beta@} @end example @code{@@math} is formatted inline when used inside a paragraph, like @math{\partial_\alpha \partial^\alpha A^\beta = \mu_0 J^\beta} in this example. The @code{@@math} command has no special effect on the Info output, merely outputting the contents verbatim. For printed output, @code{@@math} switches into @TeX{} ``math mode''. In that context, @samp{\} must be used instead of @samp{@@} for plain @TeX{} math control sequences for symbols, functions, and so on. @cindex Math output for HTML By default, the HTML output is only emphasized. @command{texi2any} provides three options for displaying properly formatted mathematics for HTML. You can select these with the @code{HTML_MATH} variable (@pxref{HTML Customization Variables}). With @code{HTML_MATH} set to @samp{l2h}, @command{texi2any} attempts to use the @command{latex2html} program to produce image files for mathematical material. With the @samp{t4h} setting, @command{texi2any} attempts to use the @command{tex4ht} program. With the @samp{mathjax} setting, @command{texi2any} inserts references in the output files to MathJax scripts to format the material. The MathJax option requires JavaScript to be enabled in the browser to work. See also @ref{MathJax Customization Variables}, @ref{@command{latex2html} Customization Variables} and @ref{@command{tex4ht} Customization Variables}. @cindex Displayed equations @cindex Equations, displayed @findex displaymath For displayed equations, you can use the @code{@@displaymath} command. Example: @example @@displaymath f(x) = @{1\over\sigma\sqrt@{2\pi@}@} e^@{-@{1\over2@}\left(@{x-\mu\over\sigma@}\right)^2@} @@end displaymath @end example @noindent which produces: @displaymath f(x) = {1\over\sigma\sqrt{2\pi}} e^{-{1\over2}\left({x-\mu\over\sigma}\right)^2} @end displaymath In general, the contents of @code{@@math} or @code{@@displaymath} should be plain @TeX{} only, with no interspersed Texinfo commands. If you do use any Texinfo commands, then you should mark these with @samp{@@} as usual, rather than @samp{\} (e.g. @samp{@@var} rather than @samp{\var}), but we do not guarantee which Texinfo commands will work. Although @code{@@sub} and @code{@@sup} may work inside math mode in some contexts, it is better to use @TeX{}'s @samp{_} and @samp{^} characters to denote subscripts and superscripts within mathematical expressions. @LaTeX{}-specific code will only work when the output format is @LaTeX{}, and with the @code{HTML_MATH} options (although @command{tex4ht} needs @code{T4H_MATH_CONVERSION} to be set to @samp{latex}; @pxref{@command{tex4ht} Customization Variables}). @ignore @findex @sortas{\} \ @r{(literal \ in @code{@@math})} Since @samp{\} is an escape character inside @code{@@math}, you can use @code{@@\} to get a literal backslash (@code{\\} will work in @TeX{}, but you'd get the literal two characters @samp{\\} in Info). @code{@@\} is not defined outside of @code{@@math}, since a @samp{\} ordinarily produces a literal (typewriter) @samp{\}. You can also use @code{@@backslashchar@{@}} in any mode to get a typewriter backslash. @xref{Inserting a Backslash}. @end ignore @findex \mathopsup Due to the conflict with Texinfo's @code{@@sup} command, you can access the plain @TeX{} command @code{\sup} as @code{\mathopsup} instead, in the unlikely occurrence that you want to do this (but only when processing with @TeX{}, not when outputting @LaTeX{} nor with any of the @code{HTML_MATH} options). @node Glyphs for Text @nodedescription Inserting dots, bullets, currencies, etc. @section Glyphs for Text @anchor{Glyphs}@c old name @anchor{TeX and copyright}@c another old node, now split into two @cindex Glyphs for text @cindex Textual glyphs Texinfo has support for a few additional glyphs that are commonly used in printed text but not available in ASCII@. Of course, there are many thousands more. It is possible to use Unicode characters as-is as far as @code{texi2any} is concerned, but @TeX{} is not so lucky. @node @code{@@TeX @@LaTeX} @nodedescription The @TeX{} logos. @subsection @code{@@TeX}@{@} (@TeX{}) and @code{@@LaTeX}@{@} (@LaTeX{}) @anchor{tex}@c old name @findex TeX @findex LaTeX @cindex Logos, @TeX{} @cindex @TeX{} logo @cindex @LaTeX{} logo Use the @code{@@TeX@{@}} command to generate `@TeX{}'. In a printed manual, this is a special logo that is different from three ordinary letters. In other output formats, it just looks like @samp{TeX}. Similarly, use the @code{@@LaTeX@{@}} command to generate `@LaTeX{}', which is even more special in printed manuals (and different from the incorrect @code{La@@TeX@{@}}. In other output formats, the result is just @samp{LaTeX}. The spelling of these commands is unusual for Texinfo, in that they use both uppercase and lowercase letters. @node @code{@@copyright} @nodedescription The copyright symbol (c in a circle). @subsection @code{@@copyright@{@}} (@copyright{}) @anchor{copyright symbol}@c old name @findex copyright @cindex Copyright symbol Use the @code{@@copyright@{@}} command to generate the copyright symbol, `@copyright{}'. Where possible, this is a @samp{c} inside a circle; otherwise this is @samp{(C)}. Legally, it's not necessary to use the copyright symbol; the English word `Copyright' suffices, according to international treaty. @node @code{@@registeredsymbol} @nodedescription The registered symbol (R in a circle). @subsection @code{@@registeredsymbol@{@}} (@registeredsymbol{}) @anchor{registered symbol}@c old name @findex registeredsymbol @cindex Registered symbol Use the @code{@@registeredsymbol@{@}} command to generate the registered symbol, `@registeredsymbol{}'. Where possible, this is an @samp{R} inside a circle; otherwise this is @samp{(R)}. @node @code{@@dots} @nodedescription How to insert ellipses: @dots{} and @enddots{} @subsection @code{@@dots} (@dots{}) and @code{@@enddots} (@enddots{}) @anchor{dots}@c old name @findex dots @findex enddots @cindex Inserting dots @cindex Inserting ellipsis @cindex Dots, inserting @cindex Ellipsis, inserting @anchor{Dots Bullets}@c old name An @dfn{ellipsis} (a sequence of dots) would be spaced wrong when typeset as a string of periods, so a special command is used in Texinfo: use the @code{@@dots@{@}} command to generate a normal ellipsis, which is three dots in a row, appropriately spaced @dots{} like so. To emphasize: do not simply write three periods in the input file; that could work in some output formats, but would produce the wrong amount of space between the periods in printed manuals. The @code{@@enddots@{@}} command generates an end-of-sentence ellipsis, which also has three dots, but with different spacing afterwards, @enddots{} Look closely to see the difference. Here is an ellipsis: @dots{} Here are three periods in a row: ... In printed (and usually HTML) output, the three periods in a row are much closer together than the dots in the ellipsis. @node @code{@@bullet} @nodedescription How to insert a bullet: @bullet{} @subsection @code{@@bullet} (@bullet{}) @anchor{bullet}@c old name @findex bullet Use the @code{@@bullet@{@}} command to generate a large round dot, or the closest possible thing to one. An asterisk can also be used. Here is a bullet: @bullet{} When you use @code{@@bullet} in @code{@@itemize}, you do not need to type the braces, because @code{@@itemize} supplies them. (@pxref{@code{@@itemize}}). @node @code{@@euro} @nodedescription How to insert the euro currency symbol. @subsection @code{@@euro} (@euro{}): Euro Currency Symbol @anchor{euro}@c old name @findex euro @cindex Euro symbol, producing Use the @code{@@euro@{@}} command to generate `@euro{}'. Where possible, this is the symbol for the Euro currency. Otherwise, the word @samp{Euro} is used. @pindex feymr10 @cindex Euro font The Euro symbol does not exist in the standard @TeX{} fonts (which were designed before the Euro was legislated into existence). Therefore, @TeX{} uses an additional font, named @code{feymr10} (along with other variables). It is freely available, of course; you can download it from @url{http://ctan.org/pkg/eurosym}, among other places. The distribution includes installation instructions. @node @code{@@pounds} @nodedescription How to insert the pounds currency symbol. @subsection @code{@@pounds} (@pounds{}): Pounds Sterling @anchor{pounds}@c old name @findex pounds @cindex Pounds symbol Use the @code{@@pounds@{@}} command to generate `@pounds{}'. Where possible, this is the symbol for the pounds sterling British currency. Otherwise, it is @samp{#}. @node @code{@@textdegree} @nodedescription How to insert the degrees symbol. @subsection @code{@@textdegree} (@textdegree{}): Degrees Symbol @anchor{textdegree}@c old name @findex textdegree @cindex Degree symbol Use the @code{@@textdegree@{@}} command to generate `@textdegree{}'. Where possible, this is the normal symbol for degrees. Otherwise, it is an @samp{o}. @node @code{@@minus} @nodedescription How to insert a minus sign. @subsection @code{@@minus} (@minus{}): Inserting a Minus Sign @anchor{minus}@c old name @findex minus @cindex Minus sign @cindex Em dash, compared to minus sign @cindex Hyphen, compared to minus Use the @code{@@minus@{@}} command to generate a minus sign. Where the character encoding and font used in the output allow it, the symbol is the customary length for a minus sign---a little longer than a hyphen, shorter than an em-dash: @display @samp{@minus{}} is a minus sign generated with @samp{@@minus@{@}}, `-' is a hyphen generated with the character @samp{-}, `---' is an em-dash for text. @end display If you actually want to typeset some math that does a subtraction, it is better to use @code{@@math}, as in @code{@@math@{a-b@}} (@pxref{Inserting Math}). @node @code{@@geq @@leq} @nodedescription How to insert greater/less-than-or-equal signs. @subsection @code{@@geq} (@geq{}) and @code{@@leq} (@leq{}): Inserting Relations @anchor{geq leq}@c old name @findex geq @findex leq Use the @code{@@geq@{@}} and @code{@@leq@{@}} commands to generate greater-than-or-equal and less-than-equal-signs, `@geq{}' and `@leq{}'. When those symbols are not available, the ASCII sequences @samp{>=} and @samp{<=} are output. @node Glyphs for Programming @nodedescription Indicating results of evaluation, expansion of macros, errors, etc. @section Glyphs for Programming @cindex Glyphs for programming @cindex Examples, glyphs for @cindex Programming, glyphs for In Texinfo, code is often illustrated in examples that are delimited by @code{@@example} and @code{@@end example}. In such examples, you can indicate the results of evaluation or an expansion using @samp{@result{}} or @samp{@expansion{}}. Likewise, there are commands to insert glyphs to indicate printed output, error messages, equivalence of expressions, the location of point in an editor, and GUI operation sequences. The glyph-insertion commands do not need to be used within an example, but most often they are. All glyph-insertion commands are followed by empty braces. @node Glyphs Summary @nodedescription List of the glyph commands. @subsection Glyphs Summary Here is a summary of the glyph commands: @table @asis @item @result{} @code{@@result@{@}} indicates the result of an expression. @item @expansion{} @code{@@expansion@{@}} indicates the results of a macro expansion. @item @print{} @code{@@print@{@}} indicates printed output. @item @error{} @code{@@error@{@}} indicates the following text is an error message. @item @equiv{} @code{@@equiv@{@}} indicates the exact equivalence of two forms. @item @point{} @code{@@point@{@}} shows the location of point. @item @clicksequence{A @click{} B} @code{@@clicksequence@{A @@click@{@} B@}} indicates a GUI operation sequence: first A, then clicking B, or choosing B from a menu, or otherwise selecting it. @end table @node @code{@@result} @nodedescription How to show the result of expression. @subsection @code{@@result@{@}} (@result{}): Result of an Expression @anchor{result}@c old name @findex result @cindex Result of an expression @cindex Indicating evaluation @cindex Evaluation glyph @cindex Value of an expression, indicating Use the @code{@@result@{@}} command to indicate the result of evaluating an expression. The @code{@@result@{@}} command is displayed as @samp{@result{}}, either a double stemmed arrow or (when that is not available) the ASCII sequence @samp{=>}. Thus, the following, @example lisp (cdr '(1 2 3)) @result{} (2 3) @end example @noindent may be read as ``@code{(cdr '(1 2 3))} evaluates to @code{(2 3)}''. @node @code{@@expansion} @nodedescription How to indicate an expansion. @subsection @code{@@expansion@{@}} (@expansion{}): Indicating an Expansion @anchor{expansion}@c old name @cindex Expansion, indicating @cindex Macro expansion, indicating @findex expansion When an expression is a macro call, it expands into a new expression. You can indicate the result of the expansion with the @code{@@expansion@{@}} command. The @code{@@expansion@{@}} command is displayed as @samp{@expansion{}}, either a long arrow with a flat base or (when that is not available) the ASCII sequence @samp{==>}. @need 700 For example, the following @example @group @@example lisp (third '(a b c)) @@expansion@{@} (car (cdr (cdr '(a b c)))) @@result@{@} c @@end example @end group @end example @noindent produces @example lisp @group (third '(a b c)) @expansion{} (car (cdr (cdr '(a b c)))) @result{} c @end group @end example @noindent which may be read as: @quotation @code{(third '(a b c))} expands to @code{(car (cdr (cdr '(a b c))))}; the result of evaluating the expression is @code{c}. @end quotation @noindent Often, as in this case, an example looks better if the @code{@@expansion@{@}} and @code{@@result@{@}} commands are indented. @node @code{@@print} @nodedescription How to indicate generated output. @subsection @code{@@print@{@}} (@print{}): Indicating Generated Output @anchor{Print Glyph}@c old name @findex print @cindex Printed output, indicating Sometimes an expression will generate output during its execution. You can indicate such displayed output with the @code{@@print@{@}} command. The @code{@@print@{@}} command is displayed as @samp{@print{}}, either a horizontal dash butting against a vertical bar or (when that is not available) the ASCII sequence @samp{-|}. In the following example, the printed text is indicated with @samp{@print{}}, and the value of the expression follows on the last line. @example lisp @group (progn (print 'foo) (print 'bar)) @print{} foo @print{} bar @result{} bar @end group @end example @noindent In a Texinfo source file, this example is written as follows: @example @group @@example lisp (progn (print 'foo) (print 'bar)) @@print@{@} foo @@print@{@} bar @@result@{@} bar @@end example @end group @end example @node @code{@@error} @nodedescription How to indicate an error message. @subsection @code{@@error@{@}} (@error{}): Indicating an Error Message @anchor{Error Glyph}@c old name @cindex Error message, indicating @findex error A piece of code may cause an error when you evaluate it. You can designate the error message with the @code{@@error@{@}} command. The @code{@@error@{@}} command is displayed as @samp{@error{}}, either the word `error' in a box in the printed output, the word error followed by an arrow in other formats or (when no arrow is available) @samp{error-->}. @need 700 Thus, @example @@example lisp (+ 23 'x) @@error@{@} Wrong type argument: integer-or-marker-p, x @@end example @end example @noindent produces @example lisp (+ 23 'x) @error{} Wrong type argument: integer-or-marker-p, x @end example @noindent This indicates that the following error message is printed when you evaluate the expression: @example lisp Wrong type argument: integer-or-marker-p, x @end example The word @samp{@error{}} itself is not part of the error message. @node @code{@@equiv} @nodedescription How to indicate equivalence. @subsection @code{@@equiv@{@}} (@equiv{}): Indicating Equivalence @anchor{Equivalence}@c oldname @cindex Equivalence, indicating @findex equiv Sometimes two expressions produce identical results. You can indicate the exact equivalence of two forms with the @code{@@equiv@{@}} command. The @code{@@equiv@{@}} command is displayed as @samp{@equiv{}}, either a standard mathematical equivalence sign (three parallel horizontal lines) or (when that is not available) as the ASCII sequence @samp{==}. Thus, @example @@example lisp (make-sparse-keymap) @@equiv@{@} (list 'keymap) @@end example @end example @noindent produces @example lisp (make-sparse-keymap) @equiv{} (list 'keymap) @end example @noindent This indicates that evaluating @code{(make-sparse-keymap)} produces identical results to evaluating @code{(list 'keymap)}. @node @code{@@point} @nodedescription How to indicate the location of point. @subsection @code{@@point@{@}} (@point{}): Indicating Point in a Buffer @anchor{Point Glyph}@c old name @cindex Point, indicating in a buffer @findex point Sometimes you need to show an example of text in an Emacs buffer. In such examples, the convention is to include the entire contents of the buffer in question between two lines of dashes containing the buffer name. You can use the @samp{@@point@{@}} command to show the location of point in the text in the buffer. (The symbol for point, of course, is not part of the text in the buffer; it indicates the place @emph{between} two characters where point is located.) The @code{@@point@{@}} command is displayed as @samp{@point{}}, either a pointed star or (when that is not available) the ASCII sequence @samp{-!-}. The following example shows the contents of buffer @file{foo} before and after evaluating a Lisp command to insert the word @code{changed}. @example @group ---------- Buffer: foo ---------- This is the @point{}contents of foo. ---------- Buffer: foo ---------- @end group @end example @example @group (insert "changed ") @result{} nil ---------- Buffer: foo ---------- This is the changed @point{}contents of foo. ---------- Buffer: foo ---------- @end group @end example In a Texinfo source file, the example is written like this: @example @@example ---------- Buffer: foo ---------- This is the @@point@{@}contents of foo. ---------- Buffer: foo ---------- (insert "changed ") @@result@{@} nil ---------- Buffer: foo ---------- This is the changed @@point@{@}contents of foo. ---------- Buffer: foo ---------- @@end example @end example @node Click Sequences @nodedescription Inserting GUI usage sequences. @subsection Click Sequences @cindex Click sequences @cindex Sequence of clicks @cindex GUI click sequence @findex clicksequence When documenting graphical interfaces, it is necessary to describe sequences such as `Click on @samp{File}, then choose @samp{Open}, then @dots{}'. Texinfo offers commands @code{@@clicksequence} and @code{click} to represent this, typically used like this: @example @dots{} @@clicksequence@{File @@click@{@} Open@} @dots{} @end example @noindent which produces: @display @dots{} @clicksequence{File @click{} Open} @dots{} @end display @findex click @findex arrow The @code{@@click} command produces a right arrow by default; this glyph is also available independently via the command @code{@@arrow@{@}}. @findex clickstyle You can change the glyph produced by @code{@@click} with the command @code{@@clickstyle}, which takes a command name as its single argument on the rest of the line, much like @code{@@itemize} and friends (@pxref{@code{@@itemize}}). The command should produce a glyph, and the usual empty braces @samp{@{@}} are omitted. Here's an example: @example @@clickstyle @@result @dots{} @@clicksequence@{File @@click@{@} Open@} @dots{} @end example @noindent now produces: @display @clickstyle @result @dots{} @clicksequence{File @click{} Open} @dots{} @end display @node Inserting Unicode @nodedescription Inserting a Unicode character by code point. @section Inserting Unicode: @code{@@U} @cindex Unicode character, inserting @cindex Code point of Unicode character, inserting by @findex U The command @code{@@U@{@var{hex}@}} inserts a representation of the Unicode character U+@var{hex}. For example, @code{@@U@{0132@}} inserts the Dutch `IJ' ligature (`@U{0132}'). The @var{hex} value should be at least four hex digits; leading zeros are @emph{not} added. In general, @var{hex} must specify a valid normal Unicode character; e.g., U+10FFFF (the very last code point) is invalid by definition, and thus cannot be inserted this way. @cindex ASCII, source document portability using @code{@@U} is useful for inserting occasional glyphs for which Texinfo has no dedicated command, while allowing the Texinfo source to remain purely 7-bit ASCII for maximum portability. @cindex Unicode and @TeX{} This command has many limitations---the same limitations as inserting Unicode characters in UTF-8 or another binary form. First and most importantly, @TeX{} knows nothing about most of Unicode. Supporting specific additional glyphs upon request is possible, but it's not viable for @file{texinfo.tex} to support whole additional scripts (Japanese, Urdu, @dots{}). The @code{@@U} command does nothing to change this. If the specified character is not supported in @TeX{}, an error is given. @LaTeX{} output has more possibilities regarding UTF-8, but could require extra code to load fonts and declare how UTF-8 characters are output. (@xref{@code{@@documentencoding}}.) @cindex Entity reference in HTML et al. @cindex @samp{&#x@var{hex};}, output from @code{@@U} In HTML and DocBook, the output from @code{@@U} is always an entity reference of the form @samp{&#x@var{hex};}, as in @samp{IJ} for the example above. This should work even when an HTML document uses some other encoding (say, Latin@tie{}1) and the given character is not supported in that encoding. In Info and plain text, if the output encoding is not UTF-8, the output is the ASCII sequence @samp{U+@var{hex}}, as in the six ASCII characters @samp{U+0132} for the example above. @node Breaks @nodedescription Forcing or preventing line and page breaks. @chapter Forcing and Preventing Breaks @cindex Forcing line and page breaks @cindex Making line and page breaks @cindex Preventing line and page breaks @cindex Line breaks @subentry awkward @cindex Page breaks, awkward Line and page breaks can sometimes occur in the `wrong' place in one or another form of output. It's up to you to ensure that text looks right in all the output formats. For example, in a printed manual, page breaks may occur awkwardly in the middle of an example; to prevent this, you can hold text together using a grouping command that keeps the text from being split across two pages. Conversely, you may want to force a page break where none would normally occur. You can use the break, break prevention, or pagination commands to fix problematic line and page breaks. @node Break Commands @nodedescription Summary of break-related commands. @section Break Commands The break commands create or allow line and paragraph breaks: @table @code @item @@* Force a line break. @item @@sp @var{n} Skip @var{n} blank lines. @item @@- Insert a discretionary hyphen. @item @@hyphenation@{@var{hy-phen-a-ted words}@} Define hyphen points in @var{hy-phen-a-ted words}. @end table These commands hold text together on a single line: @table @code @item @@w@{@var{text}@} Prevent @var{text} from being split and hyphenated across two lines. @item @@tie@{@} Insert a normal interword space at which a line break may not occur. @end table The pagination commands apply only to printed output, since other output formats do not have pages. @table @code @item @@page Start a new page. @item @@group Hold text together that must appear on one page. @item @@need @var{mils} Start a new page if not enough space on this one. @end table @node Line Breaks @nodedescription Forcing line breaks. @section @code{@@*} and @code{@@/}: Generate and Allow Line Breaks @findex * @r{(force line break)} @findex / @r{(allow line break)} @ifset commandlookup @findex * @findex / @end ifset @cindex Line breaks @subentry controlling @cindex Controlling line breaks @cindex Breaks in a line @cindex Force line break @cindex Allow line break The @code{@@*} command forces a line break in all output formats. The @code{@@/} command allows a line break (printed manual only). Here is an example with @code{@@*}: @example This sentence is broken @@*into two lines. @end example @noindent produces @example @group This sentence is broken into two lines. @end group @end example The @code{@@/} command can be useful within long URLs or other identifiers where @TeX{} can't find a good place to break. @TeX{} will automatically break URLs at the natural places (@pxref{URL Line Breaking}), so only use @code{@@/} if you need it. @code{@@/} has no effect on the other output formats. @node @code{@@- @@hyphenation} @nodedescription Helping @TeX{} with hyphenation points. @section @code{@@-} and @code{@@hyphenation}: Hyphenation in Printed Output @anchor{- and hyphenation}@c old name @findex @sortas{-} - @r{(discretionary hyphen)} @ifset commandlookup @findex @sortas{-} - @end ifset @findex hyphenation @cindex Hyphenation, helping @TeX{} do @cindex Fine-tuning, and hyphenation Although @TeX{}'s hyphenation algorithm is generally pretty good, it does miss useful hyphenation points from time to time. (Or, far more rarely, insert an incorrect hyphenation.) So, for documents with an unusual vocabulary or when fine-tuning for a printed edition, you may wish to specify hyphenation points explicitly. Texinfo supports two commands for this: @table @code @item @@- Insert a discretionary hyphen, i.e., a place where a word can be broken across lines with a hyphen. This is especially useful when you notice that an overfull hbox is due to @TeX{} missing a hyphenation (@pxref{Overfull hboxes}). @TeX{} will not insert any hyphenation points itself into a word containing @code{@@-}. @item @@hyphenation@{@var{hy-phen-a-ted words}@} Give hyphenation points for certain words. For example: @example @@hyphenation@{man-u-script man-u-scripts@} @end example @noindent As shown, you put a @samp{-} at each hyphenation point. @TeX{} only uses the specified hyphenation points when the words match exactly, so give all necessary variants, such as plurals. @end table Non-printed output is not hyphenated, so none of these commands have any effect in other output formats. @node @code{@@allowcodebreaks} @nodedescription Controlling line breaks within @@code text. @section @code{@@allowcodebreaks}: Control Line Breaks in @code{@@code} @anchor{allowcodebreaks}@c old name @findex allowcodebreaks @cindex Breaks, within @code{@@code} @cindex @sortas{-} -, breakpoint within @code{@@code} @cindex Hyphen, breakpoint within @code{@@code} @cindex Dash, breakpoint within @code{@@code} @cindex _, breakpoint within @code{@@code} @cindex Underscore, breakpoint within @code{@@code} Ordinarily, @TeX{} considers breaking lines at @samp{-} and @samp{_} characters within @code{@@code} and related commands (@pxref{@code{@@code}}), more or less as if they were ``empty'' hyphenation points. This is necessary since many manuals, especially for Lisp-family languages, must document very long identifiers. On the other hand, some manuals don't have this problem, and you may not wish to allow a line break at the underscore in, for example, @code{SIZE_MAX}, or even worse, after any of the four underscores in @code{__typeof__}. So Texinfo provides this command: @example @@allowcodebreaks false @end example @noindent to prevent from breaking at @samp{-} or @samp{_} within @code{@@code}. You can go back to allowing such breaks with @code{@@allowcodebreaks true}. Write these commands on lines by themselves. These commands can be given anywhere in the document. For example, you may have just one problematic paragraph where you need to turn off the breaks, but want them in general, or vice versa. This command has no effect except in @TeX{} output. @node @code{@@w} @nodedescription Preventing unwanted line breaks in text. @section @code{@@w}@{@var{text}@}: Prevent Line Breaks @anchor{w}@c old name @findex w @cindex Line breaks, preventing @code{@@w@{@var{text}@}} outputs @var{text}, while prohibiting line breaks within @var{text}. @cindex Non-breakable space, fixed @cindex Unbreakable space, fixed Thus, you can use @code{@@w} to produce a non-breakable space, fixed at the width of a normal interword space: @example @@w@{ @} @@w@{ @} @@w@{ @} indentation. @end example @noindent produces: @display @w{ } @w{ } @w{ } indentation. @end display The space from @code{@@w@{@w{ }@}}, as well as being non-breakable, also will not stretch or shrink. Sometimes that is what you want, for instance if you're doing manual indenting. However, usually you want a normal interword space that does stretch and shrink (in the printed output); for that, see the @code{@@tie} command in the next section. @cindex Hyphenation, preventing In printed output, you can also use the @code{@@w} command to prevent a long name or phrase being automatically hyphenated, for example if it happens to fall near the end of a line. @cindex Keyword expansion, preventing @cindex Version control keywords, preventing expansion of @cindex $Id expansion, preventing You can also use @code{@@w} to avoid unwanted keyword expansion in source control systems. For example, to literally write @t{@w{$}Id$} in your document, use @code{@@w@{$@}Id$}. This trick isn't effective for output files in some output formats, though. @node @code{@@tie} @nodedescription Inserting an unbreakable but varying space. @section @code{@@tie@{@}}: Inserting an Unbreakable Space @anchor{tie}@c old name @findex tie @cindex Tied space @cindex Non-breakable space, variable @cindex Unbreakable space, variable The @code{@@tie@{@}} command produces a normal interword space at which a line break may not occur. Always write it with following (empty) braces, as usual for commands used within a paragraph. Here's an example: @example @@TeX@{@} was written by Donald E.@@tie@{@}Knuth. @end example @noindent produces: @display @TeX{} was written by Donald E.@tie{}Knuth. @end display There are two important differences between @code{@@tie@{@}} and @code{@@w@{@w{ }@}}: @itemize @item The space produced by @code{@@tie@{@}} will stretch and shrink slightly along with the normal interword spaces in the paragraph; the space produced by @code{@@w@{@w{ }@}} will not vary. @item @code{@@tie@{@}} allows hyphenation of the surrounding words, while @code{@@w@{@w{ }@}} inhibits hyphenation of those words (for @TeX{}nical reasons, namely that it produces an @samp{\hbox}). @end itemize @node @code{@@sp} @nodedescription Inserting blank lines. @section @code{@@sp} @var{n}: Insert Blank Lines @anchor{sp}@c old name @findex sp @cindex Space, inserting vertical @cindex Blank lines @cindex Line spacing A line beginning with and containing only @code{@@sp @var{n}} generates @var{n} blank lines of space. @code{@@sp} also forces a paragraph break. For example, @example @@sp 2 @end example @noindent generates two blank lines. The @code{@@sp} command is most often used in the title page. @node @code{@@page} @nodedescription Forcing the start of a new page. @section @code{@@page}: Start a New Page @anchor{page}@c old name @findex page @cindex Page breaks, forcing A line containing only @code{@@page} starts a new page in a printed manual. In other formats, without the concept of pages, it starts a new paragraph. A @code{@@page} command is often used in the @code{@@titlepage} section of a Texinfo file to start the copyright page. @node @code{@@group} @nodedescription Preventing unwanted page breaks. @section @code{@@group}: Prevent Page Breaks @anchor{group}@c old name @findex group @cindex Group (hold text together vertically) @cindex Holding text together vertically @cindex Vertically holding text together The @code{@@group} command is used to hold an example together on one page. Use it inside an @code{@@example} or similar construct to begin an unsplittable vertical group, which will appear entirely on one page in the printed output. Terminate the group by a line containing only @code{@@end group}. This command has an effect in @TeX{} output only. @need 750 The @code{@@group} and @code{@@end group} commands need to be inside the @code{@@example} and @code{@@end example} commands, thus: @example @group @@example @@group @dots{} @@end group @@end example @end group @end example Although @code{@@group} would make sense conceptually in a wide variety of contexts, its current implementation works only within @code{@@example} and variants, and within @code{@@display}, @code{@@format}, @code{@@flushleft} and @code{@@flushright}. @xref{Quotations and Examples}. (What all these commands have in common is that each line of input produces a line of output.) @c In other contexts, @code{@@group} can cause anomalous vertical @c spacing. @c commented out below because all TeX errors are strange and unfathomable, @c not just for @group @c If you forget to end a group, you may get strange and unfathomable @c error messages when you run @TeX{}. This is because @TeX{} keeps @c trying to put the rest of the Texinfo file onto the one page and does @c not start to generate error messages until it has processed @c considerable text. It is a good rule of thumb to look for a missing @c @code{@@end group} if you get incomprehensible error messages in @c @TeX{}. @node @code{@@need} @nodedescription Another way to prevent unwanted page breaks. @section @code{@@need @var{mils}}: Prevent Page Breaks @anchor{need}@c old name @findex need @cindex Need space at page bottom @cindex Mils, argument to @code{@@need} A line containing only @code{@@need @var{n}} starts a new page in a printed manual if fewer than @var{n} mils (thousandths of an inch) remain on the current page. Do not use braces around the argument @var{n}. The @code{@@need} command has no effect on other output formats since they are not paginated. @need 800 This paragraph is preceded by a @code{@@need} command that starts a new page in printed output if fewer than 800 mils (eight-tenths inch) remain on the page. It looks like this: @example @group @@need 800 This paragraph is preceded by @dots{} @end group @end example @cindex Orphans, preventing The @code{@@need} command is useful for preventing orphans: single lines at the bottoms of printed pages. @node Definition Commands @nodedescription Describing functions and the like uniformly. @chapter Definition Commands @cindex Definition commands The @code{@@deffn} command and the other @dfn{definition commands} enable you to describe functions, variables, macros, commands, user options, special forms and other entities in a uniform format. In the output, the name of the entity is shown with any arguments, along with the entity category ---`Function', `Variable', or whatever. Underneath, the body of the definition is indented. The name of the entity is also entered into the appropriate index. All the definition commands follow a similar format. This chapter starts by describing @code{@@deffn} before detailing all the other definition commands. @node Def Cmd Template @nodedescription Writing descriptions using definition commands. @section The Template for a Definition @cindex Definition template @cindex Template for a definition @example @group @@deffn @var{category} @var{name} @var{arguments}@dots{} @var{body-of-definition} @@end deffn @end group @end example @noindent The @code{@@deffn} command is used for definitions of entities that resemble functions---entities that may take arguments. Write the @code{@@deffn} command at the beginning of a line and follow it on the same line by the category of the entity, the name of the entity itself, and its arguments (if any). Then write the body of the definition on succeeding lines. Finally, end the definition with an @code{@@end deffn} command written on a line of its own. @need 700 @noindent For example, @example @group @@deffn Command forward-word count This command moves point forward @@var@{count@} words (or backward if @@var@{count@} is negative). @dots{} @@end deffn @end group @end example @noindent produces @quotation @deffn Command forward-word count This command moves point forward @var{count} words (or backward if @var{count} is negative). @dots{} @end deffn @end quotation Capitalize the category name like a title. If the name of the category contains spaces, as in the phrase `Interactive Command', enclose it in braces. For example: @example @group @@deffn @{Interactive Command@} isearch-forward @dots{} @@end deffn @end group @end example @noindent Otherwise, the second word will be mistaken for the name of the entity. As a general rule, when any of the arguments in the heading line @emph{except} the last one are more than one word, you need to enclose them in braces. This may also be necessary if the text contains commands, for example, @samp{@{declaraci@@'on@}} if you are writing in Spanish. The category is output in a different location for different output formats. For example, in the Info file, the category appears at the beginning of the first line of the definition. With @TeX{} output, the category is printed next to the right margin. @code{@@deffn} enters names into the index of functions. Three predefined, specialized variations of @code{@@deffn} (@code{@@defun}, @code{@@defmac}, and @code{@@defspec}) specify the category for you: ``Function'', ``Macro'', and ``Special Form'' respectively. (In Lisp, a special form is an entity much like a function.) Similarly, the general @code{@@defvr} command is accompanied by several specialized variations for describing particular kinds of variables. @node Def Cmd Continuation Lines @nodedescription Continuing the heading over source lines. @section Definition Command Continuation Lines @cindex Continuation lines in definition commands @cindex Definition command headings, continuing @cindex @sortas{@@} @samp{@@} as continuation in definition commands The heading line of a definition command can get very long. Therefore, Texinfo has a special syntax allowing them to be continued over multiple lines of the source file: a lone @samp{@@} at the end of each line to be continued. Here's an example: @example @@defun fn-name @@ arg1 arg2 arg3 This is the basic continued defun. @@end defun @end example @noindent produces: @defun fn-name arg1 arg2 arg3 This is the basic continued defun. @end defun @noindent As you can see, the continued lines are combined, as if they had been typed on one source line. Although this example only shows a one-line continuation, continuations may extend over any number of lines, in the same way; put an @code{@@} at the end of each line to be continued. @cindex Whitespace, collapsed around continuations @cindex Collapsing whitespace around continuations In general, any number of spaces or tabs before the @code{@@} continuation character are collapsed into a single space. There is one exception: the Texinfo processors will not fully collapse whitespace around a continuation inside braces. For example: @example @@deffn @{Category @@ Name@} @dots{} @end example @noindent The output (not shown) has excess space between `Category' and `Name'. To avoid this, elide the unwanted whitespace in your input, or put the continuation @code{@@} outside braces. @code{@@} does not function as a continuation character in @emph{any} other context. Ordinarily, @samp{@@} followed by a whitespace character (space, tab, newline) produces a normal interword space (@pxref{Multiple Spaces}). @node Optional Arguments @nodedescription Handling optional and repeated arguments. @section Optional and Repeated Arguments @cindex Optional and repeated arguments @cindex Repeated and optional arguments @cindex Arguments, repeated and optional @cindex Syntax, optional & repeated arguments @cindex Meta-syntactic chars for arguments @c This is consistent with the Emacs Lisp Reference Manual. Some entities take optional or repeated arguments. One convention for indicating these uses square brackets and ellipses: an argument enclosed within square brackets is optional, and an argument followed by an ellipsis is optional and may be repeated more than once. Thus, [@var{optional-arg}] means that @var{optional-arg} is optional and @var{repeated-args}@code{@dots{}} stands for zero or more arguments. Parentheses are used when several arguments are grouped into additional levels of list structure in Lisp. Here is the definition line of an example of an imaginary (complicated) special form: @quotation @defspec foobar (var [from to [inc]]) body@dots{} @end defspec @end quotation @noindent In this example, the arguments @var{from} and @var{to} are optional, but must both be present or both absent. If they are present, @var{inc} may optionally be specified as well. These arguments are grouped with the argument @var{var} into a list, to distinguish them from @var{body}, which includes all remaining elements of the form. In a Texinfo source file, this @code{@@defspec} line is written like this: @example @@defspec foobar (var [from to [inc]]) body@@dots@{@} @end example @node No Space After Definition Name @nodedescription How to omit space after name. @section Omitting the Space After a Definition Name @vindex txidefnamenospace As a matter of style or as demanded by the syntax of a programming language, you may wish to omit any space after a name in a definition, occurring before an opening bracket. To do this, set the @samp{txidefnamenospace} flag (@pxref{@code{@@set @@value}}). For example, this input @example @@set txidefnamenospace @@deffn Builtin index (string, substring) @@dots@{@} @@end deffn @end example @noindent produces the following: @set txidefnamenospace @deffn Builtin index (string, substring) @dots{} @end deffn @clear txidefnamenospace @node @code{@@deffnx} @nodedescription Group two or more `first' lines. @section @code{@@deffnx}, et al.: Two or More `First' Lines @anchor{deffnx}@c old node @findex deffnx @cindex Two `First' Lines for @code{@@deffn} @cindex Grouping two definitions together @cindex Definitions grouped together To create two or more `first' or header lines for a definition, follow the first @code{@@deffn} line by a line beginning with @code{@@deffnx}. @need 1000 For example, @example @group @@deffn @{Interactive Command@} isearch-forward @@deffnx @{Interactive Command@} isearch-backward These two search commands are similar except @dots{} @@end deffn @end group @end example @noindent produces @deffn {Interactive Command} isearch-forward @deffnx {Interactive Command} isearch-backward These two search commands are similar except @dots{} @end deffn @findex defcvx @findex defivarx @findex defmacx @findex defmethodx @findex defoptx @findex defopx @findex defspecx @findex deftpx @findex deftypecvx @findex deftypefnx @findex deftypefunx @findex deftypeivarx @findex deftypemethodx @findex deftypeopx @findex deftypevarx @findex deftypevrx @findex defunx @findex defvarx @findex defvrx Each definition command has an `x' form: @code{@@defunx}, @code{@@defvrx}, @code{@@deftypefunx}, etc. The `x' forms work similarly to @code{@@itemx} (@pxref{@code{@@itemx}}). @node Def Cmds in Detail @nodedescription Reference for all the definition commands. @section The Definition Commands This section describes all the definition commands of Texinfo. @node Functions Commands @nodedescription Commands for functions and similar entities. @subsection Functions and Similar Entities @cindex Function definitions @cindex Command definitions @cindex Macro definitions, programming-language This section describes the commands for describing functions and similar entities with simple arguments: @table @code @findex deffn @item @@deffn @var{category} @var{name} @var{arguments}@dots{} The @code{@@deffn} command is the general definition command for functions, interactive commands, and similar entities that may take simple arguments. You must choose a term to describe the category of entity being defined; for example, ``Function'' could be used if the entity is a function. The @code{@@deffn} command is written at the beginning of a line and is followed on the same line by the category of entity being described, the name of this particular entity, and its arguments, if any. Terminate the definition with @code{@@end deffn} on a line of its own. @need 750 For example, here is a definition: @example @group @@deffn Command forward-char nchars Move point forward @@var@{nchars@} characters. @@end deffn @end group @end example @noindent This shows a rather terse definition for a ``command'' named @code{forward-char} with one argument, @var{nchars}. Where the output format allows, @code{@@deffn} uses a typewriter font for @var{name}, and a slanted font for the rest of the @var{arguments}, as would be produced by @code{@@var}. Within the text of the description, write an argument name explicitly with @code{@@var} to refer to the value of the argument. In the example above, we used @samp{@@var@{nchars@}} in this way. In the extremely unusual case when an argument name contains @samp{--}, or another character sequence which is treated specially (@pxref{Conventions}), use @code{@@code} around the special characters. This avoids the conversion to typographic en-dashes and em-dashes. @c @var also works; that's what we used to recommend. @findex defun @item @@defun @var{name} @var{arguments}@dots{} The @code{@@defun} command is the definition command for functions with simple arguments. @code{@@defun} is equivalent to @samp{@@deffn Function @dots{}}. Terminate the definition with @code{@@end defun} on a line of its own. @findex defmac @item @@defmac @var{name} @var{arguments}@dots{} The @code{@@defmac} command is the definition command for macros. @code{@@defmac} is equivalent to @samp{@@deffn Macro @dots{}} and works like @code{@@defun}. @findex defspec @item @@defspec @var{name} @var{arguments}@dots{} The @code{@@defspec} command is the definition command for special forms. (In Lisp, a special form is an entity much like a function; @pxref{Special Forms,,, elisp, GNU Emacs Lisp Reference Manual}.) @code{@@defspec} is equivalent to @samp{@@deffn @{Special Form@} @dots{}} and works like @code{@@defun}. @end table All these commands create entries in the index of functions. @node Typed Functions @nodedescription Commands for functions in typed languages. @subsection Functions in Typed Languages @cindex Typed functions @cindex Functions, in typed languages The @code{@@deftypefn} command and its variants are generic commands for describing functions. They are particularly suitable for languages in which you must declare types of variables and functions, such as C and C++. @table @code @findex deftypefn @item @@deftypefn @var{category} @var{data-type} @var{name} @var{arguments}@dots{} The @code{@@deftypefn} command is the general definition command for functions and similar entities that may take arguments and that could be typed. The @code{@@deftypefn} command is written at the beginning of a line and is followed on the same line by the category of entity being described, information on the returned value, the name of this particular entity, and its arguments, if any. @need 800 @noindent For example, @example @group @@deftypefn @{Library Function@} int foobar @@ (int @@var@{foo@}, float @@var@{bar@}) @dots{} @@end deftypefn @end group @end example produces: @quotation @deftypefn {Library Function} int foobar (int @var{foo}, float @var{bar}) @dots{} @end deftypefn @end quotation This means that @code{foobar} is a ``library function'' that returns an @code{int}, and its arguments are @var{foo} (an @code{int}) and @var{bar} (a @code{float}). @samp{Library Function} has to be enclosed in braces to make it a single argument. When using @code{@@deftypefn} command and variations, you should mark parameter names with @code{@@var} to distinguish these from data type names, keywords, and other parts of the literal syntax of the programming language. Where the output format allows, all output on the definition line is in a typewriter font by default. @code{@@var} uses an appropriate font where it occurs. If you are describing a procedure in a language that has packages, such as Ada, you might consider using @code{@@deftypefn} in the following manner: @example @group @@deftypefn stacks private push @@ (@@var@{s@}:in out stack; @@ @@var@{n@}:in integer) @dots{} @@end deftypefn @end group @end example @noindent (In these examples the @code{@@deftypefn} arguments are shown using continuations (@pxref{Def Cmd Continuation Lines}), but could be on a single line.) In this instance, the procedure is classified as belonging to the package @code{stacks} rather than classified as a `procedure' and its data type is described as @code{private}. (The name of the procedure is @code{push}, and its arguments are @var{s} and @var{n}.) Output: @deftypefn stacks private push @ (@var{s}:in out stack; @ @var{n}:in integer) @dots{} @end deftypefn @code{@@deftypefn} and variants could be used when it is convenient to interpret the arguments list as literal computer code, marking argument names with @code{@@var}. It is not necessary for any type names to appear, and you can give an empty return type as @samp{@{@}}. @ignore @c This example is flawed because @var uppercases in Info output, @c which is inappropriate for named arguments For example, for documenting the R language, you could use input like @example @@deftypefn stats @{@} t.test (@@var@{x@}, @@var@{y@} = NULL,@@ @@w@{@@var@{alternative@} = c("two.sided", "less", "greater")@},@@ @@w@{@@var@{mu@} = 0@}, @@w@{@@var@{paired@} = FALSE@},@@ @@w@{@@var@{var.equal@} = FALSE@},@@ @@w@{@@var@{conf.level@} = 0.95@}, @@dots@{@}) @dots{} @@end deftypefn @end example @noindent to get output like @deftypefn stats {} t.test (@var{x}, @var{y} = NULL,@ @w{@var{alternative} = c("two.sided", "less", "greater")},@ @w{@var{mu} = 0}, @w{@var{paired} = FALSE},@ @w{@var{var.equal} = FALSE},@ @w{@var{conf.level} = 0.95}, @dots{}) @dots{} @end deftypefn @noindent Here the @code{@@w} command is used to prevent some line breaks. @end ignore The information on return values may be used to name the return variables. For example, in Perl, returned scalars may be given the @var{$result} and @var{$status} name in the following manner: @example @@deftypefn @{Sub@} @{(@@var@{$result@}, @@var@{$status@} =)@} @@ process (@@var@{$input@}) @dots{} Set @@var@{$status@} to 0 in case of failure @dots{} @@end deftypefn @end example to get output like @deftypefn {Sub} {(@var{$result}, @var{$status}) =} process (@var{$input}) @dots{} Set @var{$status} to 0 in case of failure @dots{} @end deftypefn @code{@@deftypefn} creates an entry in the index of functions for @var{name}. @findex deftypefun @item @@deftypefun @var{data-type} @var{name} @var{arguments}@dots{} The @code{@@deftypefun} command is the specialized definition command for functions. The command is equivalent to @samp{@@deftypefn Function @dots{}}. @code{@@deftypefun} creates an entry in the index of functions for @var{name}. @end table @cindex Return type, own line for @findex deftypefnnewline Ordinarily, the return type is printed on the same line as the function name and arguments, as shown above. In source code, GNU style for typed functions is to put the return type on a line by itself. So Texinfo provides an option to do that: @code{@@deftypefnnewline on}. This affects the generic functions only---not untyped functions with simple arguments such as @code{@@deffn}, not typed variables, etc. Specifically, it affects the commands in this section, and the analogous commands for object-oriented languages, namely @code{@@deftypeop} and @code{@@deftypemethod} (@pxref{Object-Oriented Methods}). Specifying @code{@@deftypefnnewline off} reverts to the default. @node Variables Commands @nodedescription Commands for variables and similar entities. @subsection Variables and Similar Entities Here are the commands for defining variables and similar entities: @table @code @findex defvr @item @@defvr @var{category} @var{name} The @code{@@defvr} command is a general definition command for something like a variable---an entity that records a value. You must choose a term to describe the category of entity being defined; for example, ``Variable'' could be used if the entity is a variable. Write the @code{@@defvr} command at the beginning of a line and follow it on the same line by the category of the entity and the name of the entity. We recommend capitalizing the category name like a title. If the name of the category contains spaces, as in the name ``User Option'', enclose it in braces. Otherwise, the second word will be mistaken for the name of the entity. For example, @example @group @@defvr @{User Option@} fill-column This buffer-local variable specifies the maximum width of filled lines. @dots{} @@end defvr @end group @end example Terminate the definition with @code{@@end defvr} on a line of its own. @code{@@defvr} creates an entry in the index of variables for @var{name}. @findex defvar @item @@defvar @var{name} The @code{@@defvar} command is the definition command for variables. @code{@@defvar} is equivalent to @samp{@@defvr Variable @dots{}}. @need 750 For example: @example @group @@defvar kill-ring @dots{} @@end defvar @end group @end example @code{@@defvar} creates an entry in the index of variables for @var{name}. @findex defopt @cindex User options, marking @item @@defopt @var{name} The @code{@@defopt} command is the definition command for @dfn{user options}, i.e., variables intended for users to change according to taste; Emacs has many such (@pxref{Variables,,, emacs, The GNU Emacs Manual}). @code{@@defopt} is equivalent to @samp{@@defvr @{User Option@} @dots{}}. @end table @node Typed Variables @nodedescription Commands for variables in typed languages. @subsection Variables in Typed Languages @cindex Typed variables @cindex Variables, in typed languages Variables in typed languages are handled in a manner similar to functions in typed languages. @xref{Typed Functions}. The general definition command @code{@@deftypevr} corresponds to @code{@@deftypefn} and the specialized definition command @code{@@deftypevar} corresponds to @code{@@deftypefun}. @table @code @findex deftypevr @item @@deftypevr @var{category} @var{data-type} @var{name} The @code{@@deftypevr} command is the general definition command for something like a variable in a typed language---an entity that records a value. You must choose a term to describe the category of the entity being defined; for example, ``Variable'' could be used if the entity is a variable. The @code{@@deftypevr} command is written at the beginning of a line and is followed on the same line by the category of the entity being described, the data type, and the name of this particular entity. @need 800 @noindent For example: @example @group @@deftypevr @{Global Flag@} int enable @dots{} @@end deftypevr @end group @end example @noindent produces the following: @quotation @deftypevr {Global Flag} int enable @dots{} @end deftypevr @end quotation @findex deftypevar @item @@deftypevar @var{data-type} @var{name} The @code{@@deftypevar} command is the specialized definition command for variables in typed languages. @code{@@deftypevar} is equivalent to @samp{@@deftypevr Variable @dots{}}. @end table These commands create entries in the index of variables. @node Data Types @nodedescription The definition command for data types. @subsection Data Types Here is the command for data types: @table @code @findex deftp @item @@deftp @var{category} @var{name} @var{attributes}@dots{} The @code{@@deftp} command is the generic definition command for data types. The command is written at the beginning of a line and is followed on the same line by the category, by the name of the type (which is a word like @code{int} or @code{float}), and then by names of attributes of objects of that type. Thus, you could use this command for describing @code{int} or @code{float}, in which case you could use @code{data type} as the category. (A data type is a category of certain objects for purposes of deciding which operations can be performed on them.) In Lisp, for example, @dfn{pair} names a particular data type, and an object of that type has two slots called the @sc{car} and the @sc{cdr}. Here is how you would write the first line of a definition of @code{pair}. @example @group @@deftp @{Data type@} pair car cdr @dots{} @@end deftp @end group @end example @code{@@deftp} creates an entry in the index of data types. @end table @node Abstract Objects @nodedescription Commands for object-oriented programming. @subsection Object-Oriented Programming @cindex Object-oriented programming Here are the commands for formatting descriptions about abstract objects, such as are used in object-oriented programming. A class is a defined type of abstract object. An instance of a class is a particular object that has the type of the class. An instance variable is a variable that belongs to the class but for which each instance has its own value. @menu * Variables: Object-Oriented Variables. * Methods: Object-Oriented Methods. @end menu @node Object-Oriented Variables @subsubsection Object-Oriented Variables @cindex Variables, object-oriented These commands allow you to define different sorts of variables in object-oriented programming languages. @table @code @findex defcv @item @@defcv @var{category} @var{class} @var{name} The @code{@@defcv} command is the general definition command for variables associated with classes in object-oriented programming. The @code{@@defcv} command is followed by three arguments: the category of thing being defined, the class to which it belongs, and its name. For instance: @example @group @@defcv @{Class Option@} Window border-pattern @dots{} @@end defcv @end group @end example @noindent produces: @defcv {Class Option} Window border-pattern @dots{} @end defcv @code{@@defcv} creates an entry in the index of variables. @findex deftypecv @item @@deftypecv @var{category} @var{class} @var{data-type} @var{name} The @code{@@deftypecv} command is the definition command for typed class variables in object-oriented programming. It is analogous to @code{@@defcv} with the addition of the @var{data-type} parameter to specify the type of the instance variable. @example @group @@deftypecv @{Class Option@} Window int border-pattern @dots{} @@end deftypecv @end group @end example @noindent produces: @deftypecv {Class Option} Window int border-pattern @dots{} @end deftypecv @code{@@deftypecv} creates an entry in the index of variables. @findex defivar @item @@defivar @var{class} @var{name} The @code{@@defivar} command is the definition command for instance variables in object-oriented programming. @code{@@defivar} is equivalent to @samp{@@defcv @{Instance Variable@} @dots{}}. For instance: @example @group @@defivar Window border-pattern @dots{} @@end defivar @end group @end example @noindent produces: @defivar Window border-pattern @dots{} @end defivar @code{@@defivar} creates an entry in the index of variables. @findex deftypeivar @item @@deftypeivar @var{class} @var{data-type} @var{name} The @code{@@deftypeivar} command is the definition command for typed instance variables in object-oriented programming. It is analogous to @code{@@defivar} with the addition of the @var{data-type} parameter to specify the type of the instance variable. @example @group @@deftypeivar Window int border-pattern @dots{} @@end deftypeivar @end group @end example @noindent produces: @deftypeivar Window @code{int} border-pattern @dots{} @end deftypeivar @code{@@deftypeivar} creates an entry in the index of variables. @end table @node Object-Oriented Methods @subsubsection Object-Oriented Methods @cindex Methods, object-oriented These commands allow you to define different sorts of function-like entities resembling methods in object-oriented programming languages. These entities take arguments, as functions do, but are associated with particular classes of objects. @table @code @findex defop @item @@defop @var{category} @var{class} @var{name} @var{arguments}@dots{} The @code{@@defop} command is the definition command for these method-like entities with simple arguments. For example, some systems have constructs called @dfn{wrappers} that are associated with classes as methods are, but that act more like macros than like functions. You could use @code{@@defop Wrapper} to describe one of these. Sometimes it is useful to distinguish methods and @dfn{operations}. You can think of an operation as the specification for a method. Thus, a window system might specify that all window classes have a method named @code{expose}; we would say that this window system defines an @code{expose} operation on windows in general. Typically, the operation has a name and also specifies the pattern of arguments; all methods that implement the operation must accept the same arguments, since applications that use the operation do so without knowing which method will implement it. Often it makes more sense to document operations than methods. For example, window application developers need to know about the @code{expose} operation, but need not be concerned with whether a given class of windows has its own method to implement this operation. To describe this operation, you would write: @example @@defop Operation windows expose @end example The @code{@@defop} command is written at the beginning of a line and is followed on the same line by the overall name of the category of operation, the name of the class of the operation, the name of the operation, and its arguments, if any. @code{@@defop} creates an entry, such as `@code{expose} on @code{windows}', in the index of functions. @findex deftypeop @item @@deftypeop @var{category} @var{class} @var{data-type} @var{name} @var{arguments}@dots{} The @code{@@deftypeop} command is the generic definition command for operations in object-oriented programming. It is particularly suitable for typed object-oriented languages. It is similar to @code{@@defop} with the addition of the @var{data-type} parameter to specify information on the return value of the method, for example the return type. @findex defmethod @item @@defmethod @var{class} @var{name} @var{arguments}@dots{} The @code{@@defmethod} command is the definition command for methods in object-oriented programming. A method is a kind of function that implements an operation for a particular class of objects and its subclasses. @ignore @c ADR: Who cares?!? @c KB: Oh, I don't know, I think this info is crucial! In the Lisp Machine, methods actually were functions, but they were usually defined with @code{defmethod}. @end ignore @code{@@defmethod} is equivalent to @samp{@@defop Method @dots{}}. The command is written at the beginning of a line and is followed by the name of the class of the method, the name of the method, and its arguments, if any. @noindent For example: @example @group @@defmethod @code{bar-class} bar-method argument @dots{} @@end defmethod @end group @end example @noindent illustrates the definition for a method called @code{bar-method} of the class @code{bar-class}. The method takes an argument. @code{@@defmethod} creates an entry in the index of functions. @findex deftypemethod @item @@deftypemethod @var{class} @var{data-type} @var{name} @var{arguments}@dots{} The @code{@@deftypemethod} command is the definition command for methods in object-oriented languages, in particular for typed languages such as C++ and Java. It is similar to the @code{@@defmethod} command with the addition of the @var{data-type} parameter to specify information on the return value of the method, for example the return type. @end table The commands with information on return values are affected by the @code{@@deftypefnnewline} option (@pxref{Typed Functions,, Functions in Typed Languages}). @node Generic Definition Commands @nodedescription Without automatic index entries. @section Generic Definition Commands Texinfo provides commands for definitions that do not produce automatic index entries. @findex defblock @findex defline @findex deftypeline You create a generic definition environment with @samp{@@defblock} paired with @samp{@@end defblock}. Within this environment, use a @code{@@defline} or @code{@@deftypeline} line for each symbol you document. For example: @example @@defblock @@defline Macro mac (arg1, arg2) Description of mac. @@deftypeline Builtin int foo (int @@var@{bar@}) Description of foo. @@end defblock @end example @noindent This produces the output: @defblock @defline Macro mac (arg1, arg2) Description of mac. @deftypeline Builtin int foo (int @var{bar}) Description of foo. @end defblock The syntax of @code{@@defline} is similar to that of @code{@@deffn}. The first argument gives a category for the definition. Follow this with the symbol name, followed by any parameters. You should surround any arguments containing spaces with braces. You use @code{@@deftypeline} in a similar way to @code{@@deftypefn}, following the category with a data type, and marking any parameters with @code{@@var}. (@xref{Typed Functions}).) To share the same description for multiple symbols, you can put several @code{@@defline} lines together. For example: @example @@defblock @@defline Function set-var (value) @@defline @{Settable Variable@} var Description of set-var and var. @@end defblock @end example @noindent This produces the output: @defblock @defline Function set-var (value) @defline {Settable Variable} var Description of set-var and var. @end defblock It may be useful to define line macros (@pxref{Line Macros}) in combination with these commands. @node Def Cmd Conventions @nodedescription Conventions for writing definitions. @section Conventions for Writing Definitions @cindex Definition conventions @cindex Conventions for writing definitions A manual need not and should not contain more than one definition for a given name. An appendix containing a summary should use @code{@@table} rather than the definition commands. When you write a definition using @code{@@deffn}, @code{@@defun}, or one of the other definition commands, please take care to use arguments that indicate the meaning, as with the @var{count} argument to the @code{forward-word} function. Also, if the name of an argument contains the name of a type, such as @var{integer}, take care that the argument actually is of that type. @emph{Fonts.} As Texinfo is a semantic language, you should nearly never need to specify font styles with explicit font commands in definitions (@pxref{Fonts}). However, you may be need to work around problems for particular output formats and/or constructs. Here are some possibilities: @itemize @bullet @item Explicitly marking a Lisp keyword like @samp{&@var{keyword}} with @code{@@r@{&keyword@}}, producing @r{&keyword}. Note such keywords in definition arguments are (at present) rendered in roman in @TeX{}, but this formatting is not done in any other output format. @item @samp{@@r@{@@slanted@{argument@}@}}, producing @r{@slanted{argument}}, similar to @code{@@var} but avoiding upper-casing its argument in Info output. In this and the previous point, @code{@@r} resets the font from that being used in the definition line context (slanted or typewriter) to a roman, upright style. @item You could use @code{@@t} (or even @samp{@@r@{@@t@{@dots{}}, using @code{@@r} to reset font styles) to mark literal syntax on a definition line where text would otherwise be output in the slanted roman style. @code{@@code} would be inappropriate here as it adds quotation marks in Info output. @end itemize Some degree of trial and error may be needed to get the result you want. As ever, how nested font commands combine depends on the output format, so should be avoided where possible. Hopefully, such usages are kept to a minimum. One possibility is to wrap these in @code{@@macro} (@pxref{Defining New Texinfo Commands}), allowing these usages to be easily changed in the future. @ignore For example, if a metasyntactical symbol is needed and is to be formatted as slanted code, and an strongly emphasized keyword is also important for the language, the following could be used: @example @group @@macro metasymbol @{argument@} @@r@{@@t@{@@slanted@{\argument\@}@}@} @@end macro @@macro strongkeyword @{argument@} @@r@{@@strong@{\argument\@}@} @@end macro @@defun fset arg @@metasymbol@{[ +@} @@strongkeyword@{*keyword@} @dots{} @@end defun @end group @end example @noindent produces: @macro metasymbol {argument} @r{@t{@slanted{\argument\}}} @end macro @macro strongkeyword {argument} @r{@strong{\argument\}} @end macro @defun fset arg @metasymbol{[ +} @strongkeyword{*keyword} @dots{} @end defun @end ignore @node Sample Function Definition @nodedescription An example. @section A Sample Function Definition @cindex Sample function definition Here is a definition from @ref{Calling Functions,,, elisp, The GNU Emacs Lisp Reference Manual}, using the @code{@@defun} command. The name of the function, @code{apply}, follows immediately after the @code{@@defun} command and it is followed, on the same line, by the parameter list. @quotation @defun apply function @r{&rest} arguments @code{apply} calls @var{function} with @var{arguments}, just like @code{funcall} but with one difference: the last of @var{arguments} is a list of arguments to give to @var{function}, rather than a single argument. We also say that this list is @dfn{appended} to the other arguments. @code{apply} returns the result of calling @var{function}. As with @code{funcall}, @var{function} must either be a Lisp function or a primitive function; special forms and macros do not make sense in @code{apply}. @example (setq f 'list) @result{} list (apply f 'x 'y 'z) @error{} Wrong type argument: listp, z (apply '+ 1 2 '(3 4)) @result{} 10 (apply '+ '(1 2 3 4)) @result{} 10 (apply 'append '((a b c) nil (x y z) nil)) @result{} (a b c x y z) @end example An interesting example of using @code{apply} is found in the description of @code{mapcar}. @end defun @end quotation In the Texinfo source file, this example should look like this: @example @group @@defun apply function @@r@{&rest@} arguments @@code@{apply@} calls @@var@{function@} with @@var@{arguments@}, just like @@code@{funcall@} but with one difference: the last of @@var@{arguments@} is a list of arguments to give to @@var@{function@}, rather than a single argument. We also say that this list is @@dfn@{appended@} to the other arguments. @end group @group @@code@{apply@} returns the result of calling @@var@{function@}. As with @@code@{funcall@}, @@var@{function@} must either be a Lisp function or a primitive function; special forms and macros do not make sense in @@code@{apply@}. @end group @group @@example (setq f 'list) @@result@{@} list (apply f 'x 'y 'z) @@error@{@} Wrong type argument: listp, z (apply '+ 1 2 '(3 4)) @@result@{@} 10 (apply '+ '(1 2 3 4)) @@result@{@} 10 (apply 'append '((a b c) nil (x y z) nil)) @@result@{@} (a b c x y z) @@end example @end group @group An interesting example of using @@code@{apply@} is found in the description of @@code@{mapcar@}. @@end defun @end group @end example @noindent In this manual, this function is listed in the Command and Variable Index under @code{apply}. @node Internationalization @nodedescription Supporting languages other than English. @chapter Internationalization @cindex Internationalization Texinfo has some support for writing in languages other than English, although this area still needs considerable work. (If you are the one helping to translate the fixed strings written to documents, @pxref{Internationalization of Document Strings}.) For a list of the various accented and special characters Texinfo supports, see @ref{Inserting Accents}. @node @code{@@documentlanguage} @nodedescription Declaring the current language. @section @code{@@documentlanguage @var{ll}[_@var{cc}]}: Set the Document Language @anchor{documentlanguage} @findex documentlanguage @cindex Language, declaring @cindex Locale, declaring @cindex Document language, declaring The @code{@@documentlanguage} command declares the current document locale. Write it on a line by itself, near the beginning of the file. @example @@documentlanguage @var{ll}[_@var{cc}] @end example Include a two-letter ISO@tie{}639-2 language code (@var{ll}) following the command name, optionally followed by an underscore and two-letter ISO@tie{}3166 two-letter country code (@var{cc}). If you have a multilingual document, the intent is to be able to use this command multiple times, to declare each language change. If the command is not used at all, the default is @code{en_US} for US English. As with GNU Gettext (@pxref{Top,,, gettext, Gettext}), if the country code is omitted, the main dialect is assumed where possible. For example, @code{de} is equivalent to @code{de_DE} (German as spoken in Germany). @cindex Document strings, translation of For Info and other online output, this command changes the translation of various @dfn{document strings} such as ``see'' in cross-references (@pxref{Cross References}), ``Function'' in defuns (@pxref{Definition Commands}), and so on. Some strings, such as ``Node:'', ``Next:'', ``Menu:'', etc., are keywords in Info output, so are not translated there; they are translated in other output formats. In DocBook output @code{@@documentlanguage} sets the language for following sections. For @LaTeX{}, this command causes code to load the @samp{babel} package to be output in the preamble, and @code{\selectlanguage} to be output. @cindex @file{txi-@var{cc}.tex} For @TeX{}, this command causes a file @file{txi-@var{locale}.tex} to be read (if it exists). If @code{@@documentlanguage} argument contains the optional @samp{_@var{cc}} suffix, this is tried first. For example, with @code{@@documentlanguage de_DE}, @TeX{} first looks for @file{txi-de_DE.tex}, then @file{txi-de.tex}. Such a @file{txi-*} file is intended to redefine the various English words used in @TeX{} output, such as `Chapter', `See', and so on. We are aware that individual words like these cannot always be translated in isolation, and that a very different strategy would be required for ideographic (among other) scripts. Help in improving Texinfo's language support is welcome. @cindex Hyphenation patterns, language-dependent @code{@@documentlanguage} also changes @TeX{}'s current hyphenation patterns, if the @TeX{} program being run has the necessary support included. This will generally not be the case for @command{tex} itself, but will usually be the case for up-to-date distributions of the extended @TeX{} programs @command{etex} (DVI output) and @command{pdftex} (PDF output). @command{texi2dvi} will use the extended @TeX{}s if they are available (@pxref{Format with @command{texi2dvi}}). @cindex ISO 639-2 language codes @cindex ISO 3166 country codes @cindex Language codes @cindex Country codes Since the lists of language codes and country codes are updated relatively frequently, we don't attempt to list them here. The valid language codes are on the official home page for ISO@tie{}639, @url{http://www.loc.gov/standards/iso639-2/}. The country codes and the official web site for ISO@tie{}3166 can be found via @url{https://en.wikipedia.org/wiki/ISO_3166}. @node @code{@@documentencoding} @nodedescription Declaring the input encoding. @section @code{@@documentencoding @var{enc}}: Set Input Encoding @anchor{documentencoding}@c old name @findex documentencoding @cindex Encoding, declaring @cindex Input encoding, declaring @cindex Character set, declaring @cindex Document input encoding In the default case, the input and output document encoding are assumed to be UTF-8, the vast global character encoding, expressed in 8-bit bytes. UTF-8 is compatible with 7-bit ASCII. It is recommended to use UTF-8 encoding for Texinfo manuals. The @code{@@documentencoding} command declares the input document encoding, and also affects the encoding of the output. Write it on a line by itself, with a valid encoding specification following, near the beginning of the file if your document encoding is not the default encoding. @example @@documentencoding @var{enc} @end example UTF-8 should always be the best choice for the encoding. Texinfo still supports additional encodings, mainly for compatibility with older manuals@footnote{@command{texi2any} supports more encodings for Texinfo manuals, potentially all the encodings supported by both Perl and iconv (@pxref{Generic Charset Conversion,,, libc, The GNU C Library}). The support in output formats may be lacking, however, especially for @LaTeX{} output.}: @table @code @item US-ASCII Character encoding based on the English alphabet. @cindex Euro symbol, and encodings @item ISO-8859-1 @itemx ISO-8859-15 @itemx ISO-8859-2 These specify the pre-UTF-8 standard encodings for Western European (the first two) and Eastern European languages (the third), respectively. ISO 8859-15 replaces some little-used characters from 8859-1 (e.g., precomposed fractions) with more commonly needed ones, such as the Euro symbol (@euro{}). A full description of the encodings is beyond our scope here; one useful reference is @uref{http://czyborra.com/charsets/iso8859.html}. @item koi8-r This was a commonly used encoding for the Russian language before UTF-8. @item koi8-u This was a commonly used encoding for the Ukrainian language before UTF-8. @end table @cindex Local Variables section, for encoding @cindex Info output, and encoding In Info output, a so-called `Local Variables' section (@pxref{File Variables,,, emacs, The GNU Emacs Manual}) is output including the output encoding. This allows Info readers to set the encoding appropriately. It looks like this: @example Local Variables: coding: UTF-8 End: @end example By default, for Info and plain text output, @command{texi2any} outputs accent constructs and special characters (such as @code{@@'e}) as the actual UTF-8 sequence or 8-bit character in the output encoding where possible. If this is not possible, or if the option @option{--disable-encoding} is given, an ASCII transliteration is used instead. @cindex HTML output, and encodings @cindex @code{http-equiv}, and charset specification @cindex @code{<meta>} HTML tag, and charset specification In HTML output, a @samp{<meta>} tag is output, in the @samp{<head>} section of the HTML, that specifies the output encoding. Web servers and browsers cooperate to use this information so the correct encoding is used to display the page, if supported by the system. That looks like this: @example <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> @end example In HTML and @LaTeX{} output, if @code{OUTPUT_CHARACTERS} is set (@pxref{Other Customization Variables}), accent constructs and special characters, such as @code{@@'e} or @code{``}, are output as the actual UTF-8 sequence or 8-bit character in the output encoding where possible. Otherwise, HTML entities are used for those characters in HTML, and @LaTeX{} macros are used in @LaTeX{}. In DocBook output, if the encoding is different from UTF-8, an @code{encoding} attribute is added to the XML declaration. If @code{OUTPUT_CHARACTERS} is set (@pxref{Other Customization Variables}), accent constructs such as @code{@@'e} are output as the actual 8-bit or UTF-8 character in the output encoding where possible. Otherwise XML entities are used for those constructs. @cindex Computer Modern fonts In @TeX{} output, the characters which are supported in the standard Computer Modern fonts are output accordingly. For example, this means using constructed accents rather than precomposed glyphs. Using a missing character generates a warning message, as does specifying an unimplemented encoding. Although modern @TeX{} systems support nearly every script in use in the world, this wide-ranging support is not available in @file{texinfo.tex}, and it's not feasible to duplicate or incorporate all that effort. In @LaTeX{} output, code loading the @samp{inputenc} package is output based on the encoding. This, by itself, does not ensures that all the characters from the input document can be subsequently output. The fonts used in the default case should cover the specific Texinfo glyphs, but not all the possible encoded characters. You may need to load different fonts in the preamble and use @code{\DeclareUnicodeCharacter} with a UTF-8 encoding. For example: @example @@latex \DeclareUnicodeCharacter@{017B@}@{\.Z@} @@end latex @end example Cross-references between Info files in different character encodings with non-ASCII characters in node names fail. We strongly recommend using UTF-8 only as the encoding for manuals with non-ASCII characters in the destinations of cross-references. @node Conditionals @nodedescription Specifying text for only some output cases. @chapter Conditionally Visible Text @cindex Conditionally visible text @cindex Text, conditionally visible @cindex Visibility of conditional text @cindex If text conditionally visible The @dfn{conditional commands} allow you to use different text for different output formats, or for general conditions that you define. For example, you can use them to specify different text for the printed manual and the Info output. The conditional commands comprise the following categories. @itemize @bullet @item Commands specific to an output format (Info, @TeX{}, HTML, @dots{}). @item Commands specific to any output format @emph{excluding} a given one (e.g., not Info, not @TeX{}, @dots{}). @item `Raw' formatter text for any output format, passed straight through with minimal (but not zero) interpretation of @@-commands. @item Format-independent variable substitutions, and testing if a variable is set or clear. @end itemize @node Conditional Commands @nodedescription Text for a given format. @section Conditional Commands Texinfo has an @code{@@if@var{format}} environment for each output format, to allow conditional inclusion of text for a particular output format. @findex ifinfo @code{@@ifinfo} begins segments of text that should be ignored when not producing Info output, in particular in printed output. The segment of text appears only in the Info file and, for historical compatibility, the plain text output. @findex ifdocbook @findex ifhtml @findex iflatex @findex ifplaintext @findex iftex @findex ifxml The environments for the other formats are analogous: @table @code @item @@ifdocbook @dots{} @@end ifdocbook Text to appear only in the DocBook output. @item @@ifhtml @dots{} @@end ifhtml Text to appear only in the HTML output. @item @@iflatex @dots{} @@end iflatex Text to appear only in the @LaTeX{} output. @item @@ifplaintext @dots{} @@end ifplaintext Text to appear only in the plain text output. @item @@iftex @dots{} @@end iftex Text to appear only in the printed manual. @item @@ifxml @dots{} @@end ifxml Text to appear only in the XML output. @end table The @code{@@if@dots{}} and @code{@@end if@dots{}} commands must appear on lines by themselves in your source file. The newlines following the commands are (more or less) treated as whitespace, so that the conditional text is flowed normally into a surrounding paragraph. The @code{@@if@dots{}} constructs are intended to conditionalize normal Texinfo source; @pxref{Raw Formatter Commands}, for using underlying format commands directly. Here is an example showing all these conditionals: @example @@iftex This text will appear only in the printed manual. @@end iftex @@ifinfo However, this text will appear only in Info and plain text. @@end ifinfo @@ifhtml And this text will only appear in HTML. @@end ifhtml @@iflatex Moreover, this text will only appear in @@LaTeX@{@}. @@end iflatex @@ifplaintext Whereas this text will only appear in plain text. @@end ifplaintext @@ifxml Notwithstanding that this will only appear in XML@. @@end ifxml @@ifdocbook Nevertheless, this will only appear in DocBook. @@end ifdocbook @end example @noindent The preceding example produces the following line: @iftex This text will appear only in the printed manual. @end iftex @ifinfo However, this text will appear only in Info and plain text. @end ifinfo @ifhtml And this text will only appear in HTML. @end ifhtml @iflatex Moreover, this text will only appear in @LaTeX{}. @end iflatex @ifplaintext Whereas this text will only appear in plain text. @end ifplaintext @ifxml Notwithstanding that this will only appear in XML@. @end ifxml @ifdocbook Nevertheless, this will only appear in DocBook. @end ifdocbook @noindent Notice that you only see one of the input lines, depending on which version of the manual you are reading. @findex errormsg In complex documents, you may want Texinfo to issue an error message in some conditionals that should not ever be processed. The @code{@@errormsg@{@var{text}@}} command will do this; it takes one argument, the text of the error message. We mention @code{@@errormsg@{@}} here even though it is not strictly related to conditionals, since in practice it is most likely to be useful in that context. Technically, it can be used anywhere. @xref{External Macro Processors}, for a caveat regarding the line numbers which @code{@@errormsg} emits in @TeX{}. @node Conditional Not Commands @nodedescription Text for any format other than a given one. @section Conditional Not Commands @findex ifnotdocbook @findex ifnothtml @findex ifnotinfo @findex ifnotlatex @findex ifnotplaintext @findex ifnottex @findex ifnotxml You can specify text to be included in any output format @emph{other} than a given one with the @code{@@ifnot@dots{}} environments: @example @@ifnotdocbook @dots{} @@end ifnotdocbook @@ifnothtml @dots{} @@end ifnothtml @@ifnotinfo @dots{} @@end ifnotinfo @@ifnotlatex @dots{} @@end ifnotlatex @@ifnotplaintext @dots{} @@end ifnotplaintext @@ifnottex @dots{} @@end ifnottex @@ifnotxml @dots{} @@end ifnotxml @end example @noindent The @code{@@ifnot@dots{}} command and the @code{@@end} command must appear on lines by themselves in your actual source file. If the output file is being made in the given format, the region is @emph{ignored}. Otherwise, it is included. There is one exception (for historical compatibility): @code{@@ifnotinfo} text is omitted for both Info and plain text output, not just Info. To specify text which appears only in Info and not in plain text, use @code{@@ifnotplaintext}, like this: @example @@ifinfo @@ifnotplaintext This will be in Info, but not plain text. @@end ifnotplaintext @@end ifinfo @end example The regions delimited by these commands are ordinary Texinfo source as with @code{@@iftex}, not raw formatter source as with @code{@@tex} (@pxref{Raw Formatter Commands}). @node Raw Formatter Commands @nodedescription Using raw formatter commands. @section Raw Formatter Commands @cindex Raw formatter commands @cindex @TeX{} commands, using ordinary @cindex Ordinary @TeX{} commands, using @cindex Commands using raw @TeX{} @cindex Plain @TeX{} The @code{@@if@dots{}} conditionals just described must be used only with normal Texinfo source. For instance, most features of plain @TeX{} will not work within @code{@@iftex}. The purpose of @code{@@if@dots{}} is to provide conditional processing for Texinfo source, not provide access to underlying formatting features. For that, Texinfo provides so-called @dfn{raw formatter commands}. They should only be used when truly required (most documents do not need them). @findex tex @cindex Category codes, of plain @TeX{} The first raw formatter command is @code{@@tex}. You can enter plain @TeX{} completely, and use @samp{\} in the @TeX{} commands, by delineating a region with the @code{@@tex} and @code{@@end tex} commands. All plain @TeX{} commands and category codes are restored within a @code{@@tex} region. The sole exception is that the @code{@@} character still introduces a command, so that @code{@@end tex} can be recognized. Texinfo processors will not output material in such a region unless @TeX{} output is being produced. @findex \gdef @r{within @code{@@tex}} @findex \globaldefs @r{within @code{@@tex}} In complex cases, you may wish to define new @TeX{} macros within @code{@@tex}. You must use @code{\gdef} to do this, not @code{\def}, because @code{@@tex} regions are processed in a @TeX{} group. If you need to make several definitions, you may wish to set @code{\globaldefs=1} (its value will be restored to zero as usual when the group ends at @code{@@end tex}, so it won't cause problems with the rest of the document). @cindex Equation, displayed, in plain @TeX{} @cindex Displayed equation, in plain @TeX{} As an example, here is a displayed equation written in plain @TeX{}: @example @@tex $$ \chi^2 = \sum_@{i=1@}^N \left (y_i - (a + b x_i) \over \sigma_i\right)^2 $$ @@end tex @end example @noindent The output of this example will appear only in a printed manual. If you are reading this in a format not generated by @TeX{}, you will not see the equation that appears in the printed manual. @tex $$ \chi^2 = \sum_{i=1}^N \left(y_i - (a + b x_i) \over \sigma_i\right)^2 $$ @end tex @cindex HTML, including raw @findex html @cindex DocBook, including raw @findex docbook @cindex @LaTeX{}, including raw @findex latex @cindex XML, including raw @findex xml Analogously, you can use @code{@@html @dots{} @@end html} for a region of raw HTML, @code{@@docbook @dots{} @@end docbook} for a region of raw DocBook, @code{@@latex @dots{} @@end latex} for a region of raw @LaTeX{}, and @code{@@xml @dots{} @@end xml} for a region of raw XML@. The behavior of newlines in raw regions is unspecified. In all cases, in raw processing, @code{@@} retains the same meaning as in the remainder of the document. Thus, the Texinfo processors must recognize and even execute, to some extent, the contents of the raw regions, regardless of the final output format. Therefore, specifying changes that globally affect the document inside a raw region leads to unpredictable and generally undesirable behavior. For example, using the @code{@@kbdinputstyle} command inside a raw region is undefined. The remedy is simple: don't do that. @node Inline Conditionals @nodedescription Brace-delimited conditional text. @section Inline Conditionals: @code{@@inline}, @code{@@inlineifelse}, @code{@@inlineraw} @findex inlinefmt @findex inlinefmtifelse @findex inlineraw @cindex Inline conditionals @cindex Conditional commands, inline @cindex Brace-delimited conditional text @cindex Newlines, avoiding in conditionals @cindex Whitespace, controlling in conditionals Texinfo provides a set of conditional commands with arguments given within braces: @table @code @item @@inlinefmt@{@var{format}, @var{text}@} Process the Texinfo @var{text} if @var{format} output is being generated. @item @@inlinefmtifelse@{@var{format}, @var{then-text}, @var{else-text}@} Process the Texinfo @var{then-text} if @var{format} output is being generated; otherwise, process @var{else-text}. @item @@inlineraw@{@var{format}, @var{text}@} Similar, but for raw @var{text} (@pxref{Raw Formatter Commands}). @end table The supported @var{format} names are: @example docbook html info latex plaintext tex xml @end example For example, @example @@inlinefmt@{html, @@emph@{HTML-only text@}@} @end example @noindent is nearly equivalent to @example @@ifhtml @@emph@{HTML-only text@} @@end ifhtml @end example @noindent except that no whitespace is added, as happens in the latter (environment) case. In these commands, whitespace is ignored after the comma separating the arguments, as usual, but is @emph{not} ignored at the end of @var{text}. To insert a literal at sign, left brace, or right brace in one of the arguments, you must use the alphabetic commands @code{@@atchar@{@}} (@pxref{Inserting an Atsign}), and @code{@@lbracechar@{@}} or @code{@@rbracechar@{@}} (@pxref{Inserting Braces}), or the parsing will become confused. With @code{@@inlinefmtifelse}, it is also necessary to use @code{@@comma@{@}} to avoid mistaking a @samp{,} in the text for the delimiter. With @code{@@inlinefmt} and @code{@@inlineraw}, @code{@@comma@{@}} is not required (though it's fine to use it), since these commands always have exactly two arguments. For @TeX{}, the processed @var{text} cannot contain newline-delimited commands. Text to be ignored (i.e., for non-@TeX{}) can, though. Two other @code{@@inline...} conditionals complement the @code{@@ifset} and @code{@@ifclear} commands; see the next section. @node @code{@@set @@clear @@value} @nodedescription Variable tests and substitutions. @section Flags: @code{@@set}, @code{@@clear}, conditionals, and @code{@@value} @anchor{set clear value}@c old name You can direct the Texinfo formatting commands to format or ignore parts of a Texinfo file with the @code{@@set}, @code{@@clear}, @code{@@ifset}, and @code{@@ifclear} commands. Here is a summary: @table @code @item @@set @var{flag} [@var{value}] Set the variable @var{flag}, to the optional @var{value} if specified. @item @@clear @var{flag} Undefine the variable @var{flag}, whether or not it was previously defined. @item @@ifset @var{flag} If @var{flag} is set, text through the next @code{@@end ifset} command is formatted. If @var{flag} is clear, text through the following @code{@@end ifset} command is ignored. @item @@inlineifset@{@var{flag}, @var{text}@} Brace-delimited version of @code{@@ifset}. @item @@ifclear @var{flag} If @var{flag} is set, text through the next @code{@@end ifclear} command is ignored. If @var{flag} is clear, text through the following @code{@@end ifclear} command is formatted. @item @@inlineifclear@{@var{flag}, @var{text}@} Brace-delimited version of @code{@@ifclear}. @end table @node @code{@@set @@value} @nodedescription Expand a flag variable to a string. @subsection @code{@@set} and @code{@@value} @anchor{set value}@c old name @findex set @findex value @findex clear You use the @code{@@set} command to specify a value for a flag, which is later expanded by the @code{@@value} command. A @dfn{flag} (aka @dfn{variable}) name is an identifier starting with an alphanumeric, @samp{-}, or @samp{_}. Subsequent characters, if any, may not be whitespace, @samp{@@}, braces, angle brackets, or any of @samp{~`^+|}; other characters, such as @samp{%}, may work. However, it is best to use only letters and numerals in a flag name, not @samp{-} or @samp{_} or others---they will work in some contexts, but not all, due to limitations in @TeX{}. The value is the remainder of the input line, and can contain anything. @ignore However, unlike most other commands which take the rest of the line as a value, @code{@@set} need not appear at the beginning of a line. @end ignore Write the @code{@@set} command like this: @example @@set foo This is a string. @end example @noindent This sets the value of the flag @code{foo} to ``This is a string.''. The Texinfo processors then replace a @code{@@value@{@var{flag}@}} command with the string to which @var{flag} is set. Thus, when @code{foo} is set as shown above, the Texinfo processors convert this: @example @group @@value@{foo@} @exdent @r{to this:} This is a string. @end group @end example You can write a @code{@@value} command within a paragraph; but you must write a @code{@@set} command on a line of its own. If you write the @code{@@set} command like this: @example @@set foo @end example @noindent without specifying a string, the value of @code{foo} is the empty string. If you clear a previously set flag with @code{@@clear @var{flag}}, a subsequent @code{@@value@{flag@}} command will report an error. For example, if you set @code{foo} as follows: @example @@set howmuch very, very, very @end example @noindent then the processors transform @example @group It is a @@value@{howmuch@} wet day. @exdent @r{into} It is a very, very, very wet day. @end group @end example If you write @example @@clear howmuch @end example @noindent then the processors transform @example @group It is a @@value@{howmuch@} wet day. @exdent @r{into} It is a @{No value for "howmuch"@} wet day. @end group @end example @code{@@value} cannot be reliably used as the argument to an accent command (@pxref{Inserting Accents}). For example, this fails: @c This does not seems to fail with texi2any, but fails with TeX. @example @@set myletter a @@'@@value@{myletter@} @c fails! @end example @node @code{@@ifset @@ifclear} @nodedescription Format a region if a flag is set. @subsection @code{@@ifset} and @code{@@ifclear} @anchor{ifset ifclear}@c old name @findex ifset When a @var{flag} is set, the Texinfo formatting commands format text between subsequent pairs of @code{@@ifset @var{flag}} and @code{@@end ifset} commands. When the @var{flag} is cleared, the Texinfo formatting commands do @emph{not} format the text. @code{@@ifclear} operates analogously. Write the conditionally formatted text between @code{@@ifset @var{flag}} and @code{@@end ifset} commands, like this: @example @group @@ifset @var{flag} @var{conditional-text} @@end ifset @end group @end example For example, you can create one document that has two variants, such as a manual for a `large' and `small' model: @cindex Shrubbery @example You can use this machine to dig up shrubs without hurting them. @@set large @@ifset large It can also dig up fully grown trees. @@end ifset Remember to replant promptly @dots{} @end example @noindent In the example, the formatting commands will format the text between @code{@@ifset large} and @code{@@end ifset} because the @code{large} flag is set. When @var{flag} is cleared, the Texinfo formatting commands do @emph{not} format the text between @code{@@ifset @var{flag}} and @code{@@end ifset}; that text is ignored and does not appear in the output. For example, if you clear the flag of the preceding example by writing an @code{@@clear large} command after the @code{@@set large} command (but before the conditional text), then the Texinfo formatting commands ignore the text between the @code{@@ifset large} and @code{@@end ifset} commands. In the formatted output, that text does not appear; you see only the lines that say, ``You can use this machine to dig up shrubs without hurting them. Remember to replant promptly @dots{}''. @findex ifclear If a flag is cleared with a @code{@@clear @var{flag}} command, then the formatting commands format text between subsequent pairs of @code{@@ifclear} and @code{@@end ifclear} commands. But if the flag is set with @code{@@set @var{flag}}, then the formatting commands do @emph{not} format text between an @code{@@ifclear} and an @code{@@end ifclear} command; rather, they ignore that text. An @code{@@ifclear} command looks like this: @example @@ifclear @var{flag} @end example @node @code{@@inlineifset @@inlineifclear} @nodedescription Brace-delimited flag conditionals. @subsection @code{@@inlineifset} and @code{@@inlineifclear} @findex inlineifset @findex inlineifclear @cindex Flag conditionals, brace-delimited @cindex Brace-delimited flag conditionals @code{@@inlineifset} and @code{@@inlineifclear} provide brace-delimited alternatives to the @code{@@ifset} and @code{@@ifclear} forms, similar to the other @code{@@inline...} Commands (@pxref{Inline Conditionals}). The same caveats about argument parsing given there apply here too. @table @code @item @@inlineifset@{@var{var}, @var{text}@} Process the Texinfo @var{text} if the flag @var{var} is defined. @item @@inlineifclear@{@var{var}, @var{text}@} Process the Texinfo @var{text} if the flag @var{var} is not defined. @end table Except for the syntax, their general behavior and purposes is the same as with @code{@@ifset} and @code{@@ifclear}, described in the previous section. @node @code{@@value} Example @nodedescription An easy way to update edition information. @subsection @code{@@value} Example @anchor{value Example}@c old name You can use the @code{@@value} command to minimize the number of places you need to change when you record an update to a manual. @xref{GNU Sample Texts}, for the full text of an example of using this to work with Automake distributions. This example is adapted from @ref{Top,,, make, The GNU Make Manual}. @enumerate @item Set the flags: @example @group @@set EDITION 0.35 Beta @@set VERSION 3.63 Beta @@set UPDATED 14 August 1992 @@set UPDATE-MONTH August 1992 @end group @end example @item Write text for the @code{@@copying} section (@pxref{@code{@@copying}}): @example @group @@copying This is Edition @@value@{EDITION@}, last updated @@value@{UPDATED@}, of @@cite@{The GNU Make Manual@}, for @@code@{make@}, version @@value@{VERSION@}. Copyright @dots{} Permission is granted @dots{} @@end copying @end group @end example @item Write text for the title page, for people reading the printed manual: @example @group @@titlepage @@title GNU Make @@subtitle A Program for Directing Recompilation @@subtitle Edition @@value@{EDITION@}, @dots{} @@subtitle @@value@{UPDATE-MONTH@} @@page @@insertcopying @dots{} @@end titlepage @end group @end example @noindent (On a printed cover, a date listing the month and the year looks less fussy than a date listing the day as well as the month and year.) @item Write text for the Top node, for people reading the Info file: @example @group @@ifnottex @@node Top @@top Make This is Edition @@value@{EDITION@}, last updated @@value@{UPDATED@}, of @@cite@{The GNU Make Manual@}, for @@code@{make@}, version @@value@{VERSION@}. @@end ifnottex @end group @end example After you format the manual, the @code{@@value} constructs have been expanded, so the output contains text like this: @example @group This is Edition 0.35 Beta, last updated 14 August 1992, of `The GNU Make Manual', for `make', Version 3.63 Beta. @end group @end example @end enumerate When you update the manual, you change only the values of the flags; you do not need to edit the three sections. @node Testing for Texinfo Commands @nodedescription Testing if a Texinfo command is available. @section Testing for Texinfo Commands: @code{@@ifcommanddefined}, @code{@@ifcommandnotdefined} @cindex Testing for Texinfo commands @cindex Checking for Texinfo commands @cindex Texinfo commands, testing for @cindex Commands, testing for Texinfo @cindex Versions of Texinfo, adapting to @cindex Features of Texinfo, adapting to @findex ifcommanddefined @findex ifcommandnotdefined Occasionally, you may want to arrange for your manual to test if a given Texinfo command is available and (presumably) do some sort of fallback formatting if not. There are conditionals @code{@@ifcommanddefined} and @code{@@ifcommandnotdefined} to do this. For example: @example @@ifcommanddefined node Good, @@samp@{@@@@node@} is defined. @@end ifcommanddefined @end example @noindent will output the expected `Good, @samp{@@node} is defined.'. This conditional will also consider any new commands defined by the document via @code{@@macro}, @code{@@alias}, @code{@@definfoenclose}, and @code{@@def@r{(}code@r{)}index} (@pxref{Defining New Texinfo Commands}) to be true. Caveat: the @TeX{} implementation reports internal @TeX{} commands, in addition to all the Texinfo commands, as being ``defined''; the @code{texi2any} implementation is reliable in this regard, however. @pindex @file{NEWS} file for Texinfo You can check the @file{NEWS} file in the Texinfo source distribution and linked from the Texinfo home page (@url{http://www.gnu.org/software/texinfo}) to see when a particular command was added. @vindex txicommandconditionals These command-checking conditionals themselves were added in Texinfo@tie{}5.0, released in 2013---decades after Texinfo's inception. In order to test if they themselves are available, the predefined flag @code{txicommandconditionals} can be tested, like this: @example @@ifset txicommandconditionals @@ifcommandnotdefined foobarnode (Good, @@samp@{@@@@foobarnode@} is not defined.) @@end ifcommandnotdefined @@end ifset @end example Since flags (see the previous section) were added early in the existence of Texinfo, there is no problem with assuming they are available. We recommend avoiding these tests whenever possible---which is usually the case. For many software packages, it is reasonable for all developers to have a given version of Texinfo (or newer) installed, and thus no reason to worry about older versions. (It is straightforward for anyone to download and install the Texinfo source; it does not have any problematic dependencies.) The issue of Texinfo versions does not generally arise for end users. With properly distributed packages, users need not process the Texinfo manual simply to build and install the package; they can use preformatted Info (or other) output files. This is desirable in general, to avoid unnecessary dependencies between packages (@pxref{Releases,,, standards, GNU Coding Standards}). @node Conditional Nesting @nodedescription Using conditionals inside conditionals. @section Conditional Nesting @cindex Conditionals, nested @cindex Nesting conditionals Texinfo requires that for a failing conditional, the ignored text must be properly nested with respect to that failing conditional. Here's an example: @example @@ifset somevar @@ifset anothervar Both somevar and anothervar are set. @@end ifset @@ifclear anothervar Somevar is set, anothervar is not. @@end ifclear @@end ifset @end example If @samp{somevar} is not set, the whole block is skipped. To allow the processors to reliably determine which commands to consider for nesting purposes, all conditional commands must be on lines by themselves, with no text (even spaces) before or after. @ignore @c not sure what this is about Unfortunately, it's not always feasible to check that @emph{all} conditionals are properly nested, because then the processors could have to fully interpret the ignored text, which defeats the purpose of the command. Here's an example illustrating these rules: @example @@ifset a @@ifset b @@ifclear ok - ok, ignored @@end junky - ok, ignored @@end ifset @@c WRONG - missing @@end ifset. @end example @end ignore @node Defining New Texinfo Commands @nodedescription User-defined macros and aliases. @chapter Defining New Texinfo Commands @cindex Macros @cindex Defining new Texinfo commands @cindex New Texinfo commands, defining @cindex Texinfo commands, defining new @cindex User-defined Texinfo commands Texinfo provides several ways to define new commands (in all cases, it's not recommended to try redefining existing commands): @itemize @bullet @item A Texinfo @dfn{macro} allows you to define a new Texinfo command as any sequence of text and/or existing commands (including other macros). The macro can have any number of @dfn{parameters}---text you supply each time you use the macro. Incidentally, these macros have nothing to do with the @code{@@defmac} command, which is for documenting macros in the subject area of the manual (@pxref{Def Cmd Template}). @item @samp{@@linemacro} allows you to define a macro whose arguments extend to the end of the line and are separated by spaces. @item @samp{@@alias} defines a new name for an existing command. @item @samp{@@definfoenclose} allows you to define new commands with customized output for some non-printed output formats. This command is deprecated. @end itemize Most generally of all (not just for defining new commands), it is possible to invoke any external macro processor and have Texinfo recognize so-called @code{#line} directives for error reporting. If you want to do simple text substitution, @code{@@set} and @code{@@value} is the simplest approach (@pxref{@code{@@set @@clear @@value}}). @node Defining Macros @nodedescription Defining and undefining new commands. @section Defining Macros @cindex Defining macros @cindex Macro definitions, Texinfo @findex macro You use the Texinfo @code{@@macro} command to define a macro, like this: @example @@macro @var{macroname}@{@var{param1}, @var{param2}, @dots{}@} @var{text} @dots{} \@var{param1}\ @dots{} @@end macro @end example The @dfn{parameters} @var{param1}, @var{param2}, @dots{} correspond to arguments supplied when the macro is subsequently used in the document (described in the next section). @cindex Macro names, valid characters in @cindex Names of macros, valid characters of In principle, @var{macroname} should consist of alphanumerics, and (except as the first character) @samp{-}. The @samp{_} character is excluded so that macros can be called inside @code{@@math} without a following space (@pxref{Inserting Math}). However, for a macro to work consistently with @TeX{}, @var{macroname} must consist entirely of letters: no digits, hyphens, or other special characters. So, we recommend using only letters. Texinfo commands should not be redefined as macros. If a macro needs no parameters, you can define it either with an empty list (@samp{@@macro foo @{@}}) or with no braces at all (@samp{@@macro foo}). @cindex Body of a macro The definition or @dfn{body} of the macro can contain most Texinfo commands, including macro invocations. However, a macro definition that defines another macro does not work in @TeX{} due to limitations in the design of @code{@@macro}. @cindex Parameters to macros In the macro body, instances of a parameter name surrounded by backslashes, as in @samp{\@var{param1}\} in the example above, are replaced by the corresponding argument from the macro invocation. You can use parameter names any number of times in the body, including zero. @cindex Backslash in macros To get a single @samp{\} in the macro expansion, use @samp{\\}. Any other use of @samp{\} in the body yields a warning. @cindex Spaces in macros @cindex Whitespace in macros The newline characters after the @code{@@macro} line and before the @code{@@end macro} line are ignored, that is, not included in the macro body. All other whitespace is treated according to the usual Texinfo rules. @cindex Recursive macro invocations @findex rmacro To allow a macro to be used recursively, that is, in an argument to a call to itself, you must define it with @samp{@@rmacro}, like this: @example @@rmacro rmac @{arg@} a\arg\b @@end rmacro @dots{} @@rmac@{1@@rmac@{text@}2@} @end example This produces the output `a1atextb2b'. With @samp{@@macro} instead of @samp{@@rmacro}, an error message is given. @findex unmacro @cindex Macros, undefining @cindex Undefining macros You can undefine a macro @var{foo} with @code{@@unmacro @var{foo}}. It is not an error to undefine a macro that is already undefined. For example: @example @@unmacro foo @end example @node Invoking Macros @nodedescription Using a macro, once you've defined it. @section Invoking Macros @cindex Invoking macros @cindex Expanding macros @cindex Running macros @cindex Macro invocation After a macro is defined (see the previous section), you can @dfn{invoke} (use) it in your document like this: @example @@@var{macroname} @{@var{arg1}, @var{arg2}, @dots{}@} @end example @noindent and the result will be more or less as if you typed the body of @var{macroname} at that spot. For example: @example @@macro foo @{p, q@} Together: \p\ & \q\. @@end macro @@foo@{a, b@} @end example @noindent produces: @display Together: a & b. @end display @cindex Backslash, and macros Thus, the arguments and parameters are separated by commas and delimited by braces; any whitespace after (but not before) a comma is ignored. The braces are required in the invocation even when the macro takes no arguments, consistent with other Texinfo commands. For example: @example @@macro argless @{@} No arguments here. @@end macro @@argless@{@} @end example @noindent produces: @display No arguments here. @end display @cindex Comma, in macro arguments Passing macro arguments containing commas requires care, since commas also separate the arguments. To include a comma character in an argument, the most reliable method is to use the @code{@@comma@{@}} command. Another method is to surround the argument with @samp{@@asis@{@dots{}@}}. For @code{texi2any}, you can also prepend a backslash character, as in @samp{\,}, but this does not work with @TeX{}. @cindex Automatic quoting of commas for some macros @cindex Quoting, automatic for some macros It's not always necessary to worry about commas. To facilitate use of macros, two rules for @dfn{automatic quoting} are implemented: @enumerate 1 @item If a macro takes only one argument, all commas in its invocation are quoted by default. For example: @example @group @@macro TRYME@{text@} @@strong@{TRYME: \text\@} @@end macro @@TRYME@{A nice feature, though it can be dangerous.@} @end group @end example @noindent will produce the following output @example @strong{TRYME: A nice feature, though it can be dangerous.} @end example And indeed, it can. Namely, there is no control on the number of arguments passed to one-argument macros, so be careful when you invoke them. @item If a macro invocation includes another command (including a recursive invocation of itself), any commas in the nested command invocation(s) are quoted by default. For example, in @example @@say@{@@strong@{Yes, I do@}, person one@} @end example the comma after @samp{Yes} is implicitly quoted. Here's another example, with a recursive macro: @example @group @@rmacro cat@{a,b@} \a\\b\ @@end rmacro @@cat@{@@cat@{foo, bar@}, baz@} @end group @end example @noindent will produce the string @samp{foobarbaz}. @item Otherwise, a comma should be explicitly quoted, as above, for it to be treated as a part of an argument. @end enumerate @cindex Backslash, in macro arguments @cindex Braces, in macro arguments The backslash itself can be quoted in macro arguments with another backslash. For example: @example @@@var{macname} @{\\bleh@} @end example @noindent will pass the argument @samp{\bleh} to @var{macname}. @command{texi2any} also recognizes @samp{\@{} and @samp{\@}} sequences for curly braces, but these are not recognized by the implementation in @TeX{}. There should, however, rarely be a need for these, as they are only needed when a macro argument contains unbalanced braces. If a macro is defined to take exactly one argument, it can be invoked without any braces, taking all of the line after the macro name as the argument. For example: @example @@macro bar @{p@} Twice: \p\ & \p\. @@end macro @@bar aah @end example @noindent produces: @display Twice: aah & aah. @end display @noindent In these arguments, there is no escaping of special characters, so each @samp{\} stands for itself. If a macro is defined to take more than one argument, but is called with only one (in braces), the remaining arguments are set to the empty string, and no error is given. For example: @example @@macro addtwo @{p, q@} Both: \p\\q\. @@end macro @@addtwo@{a@} @end example @noindent produces simply: @display Both: a. @end display @node Macro Details @nodedescription Limitations of Texinfo macros. @section Macro Details and Caveats @cindex Macro details @cindex Details of macro usage @cindex Caveats for macro usage @cindex Macro expansion, contexts for @cindex Expansion of macros, contexts for By design, macro expansion should not happen in the following contexts: @itemize @bullet @item @code{@@macro} and @code{@@unmacro} lines; @item @code{@@if...} lines, including @code{@@ifset} and similar; @item @code{@@set}, @code{@@clear}, @code{@@value}; @item @code{@@clickstyle} lines; @item @code{@@end} lines when there is no macro expansion in the block command. @end itemize @noindent Unfortunately, @TeX{} may do some expansion in these situations, possibly yielding errors. Also, quite a few macro-related constructs cause problems with @TeX{}; some of the caveats are listed below. Thus, if you get macro-related errors when producing the printed version of a manual, you might try expanding the macros with @command{texi2any} by invoking @command{texi2dvi} with the @samp{-E} option (@pxref{Format with @command{texi2dvi}}). Or, more reliably, eschew Texinfo macros altogether and use a language designed for macro processing, such as M4 (@pxref{External Macro Processors}). @itemize @bullet @item As mentioned earlier, macro names must consist entirely of letters. @item It is not advisable to redefine any @TeX{} primitive, plain, or Texinfo command name as a macro. Unfortunately, this is a large and open-ended set of names, and the possible resulting errors are unpredictable. @item Arguments to macros taking more than one argument cannot cross lines. @item Macros containing a command which must be on a line by itself, such as a conditional, cannot be invoked in the middle of a line. Similarly, macros containing line-oriented commands or text, such as @code{@@example} environments, may behave unpredictably in @TeX{}. @item Texinfo commands in the expansion of a macro in the text of an index entry may end up being typeset as literal text (including an ``@@'' sign), instead of being interpreted with their intended meaning. @item White space is ignored at the beginnings of lines. @item Macros can't be reliably used in the argument to accent commands (@pxref{Inserting Accents}). @item The backslash escape for commas in macro arguments does not work; @code{@@comma@{@}} must be used. @item Ending a macro body with @samp{@@c} may cause text following the macro invocation to be ignored as a comment in @command{texi2any}. This is not the case when processing with @TeX{}. This was often done to ``comment out'' an unwanted newline at the end of a macro body, but this is not necessary any more, as the final newline before @samp{@@end macro} is not included in the macro body anyway. @item In general, you can't arbitrarily substitute a macro (or @code{@@value}) call for Texinfo command arguments, even when the text is the same. Texinfo is not M4 (or even plain @TeX{}). It might work with some commands, it fails with others. Best not to do it at all. For instance, this fails: @example @@macro offmacro off @@end macro @@headings @@offmacro @end example @noindent This looks equivalent to @code{@@headings off}, but for @TeX{}nical reasons, it fails with a mysterious error message (namely, @samp{Paragraph ended before @@headings was complete}). @item Expanding macros in a math context may lead to poor spacing in @TeX{} output. For example: @example @@iftex @@macro atan \\mathop@{\\rm atan@} @@end macro @@end iftex @@math@{@@atan@{@}(x)@} @end example The braces following @samp{@@atan} are treated by @TeX{} as a subformula, leading to extra space before the opening parenthesis. You can work around this by defining a raw @TeX{} macro instead: @example @@tex \gdef\atan#1@{\mathop@{\rm atan@}@} @@end tex @end example The @samp{#1} in this definition absorbs the braces, so that the spacing is as expected for the @code{\mathop} object. @item If you have problems using conditionals within a macro, an alternative is to use separate macro definitions inside conditional blocks. For example, instead of @example @group @@macro Mac @@iftex text for TeX output @@end iftex @@ifnottex text for not TeX output @@end ifnottex @@end macro @end group @end example @noindent you can do the following instead: @example @group @@iftex @@macro Mac text for TeX output @@end macro @@end iftex @@ifnottex @@macro Mac text for not TeX output @@end macro @@end ifnottex @end group @end example @item Macros cannot define macros in the natural way. To do this, you must use conditionals and raw @TeX{}. For example: @example @@ifnottex @@macro ctor @{name, arg@} @@macro \name\ something involving \arg\ somehow @@end macro @@end macro @@end ifnottex @@tex \gdef\ctor#1@{\ctorx#1,@} \gdef\ctorx#1,#2,@{\def#1@{something involving #2 somehow@}@} @@end tex @end example @end itemize The following limitations are by design: @itemize @item If you want to pass an argument with the Texinfo command @code{@@,} (to produce a cedilla, see @ref{Inserting Accents}), you have to use @code{@@value} or another workaround. Otherwise, the comma may be taken as separating the arguments. With @command{texi2any}, the comma can be escaped by a backslash. With @TeX{} another workaround need to be used, therefore we recommend using such a workaround. For example, @example @@macro mactwo@{argfirst, argsecond@} \argfirst\+\argsecond\. @@end macro @@set fc Fran@@,cois @@mactwo@{@@value@{fc@},@} @end example @noindent produces: @display Fran@,cois+. @end display @c currently @mactwo{Fran@,cois} works in TeX, but @mactwo{Franc@\,cois} @c works in texi2any. better to avoid commas altogether using this trick. @c an alternative to @, could be invented if needed. @item @code{@@verbatim} and macros do not mix; for instance, you can't start a verbatim block inside a macro and end it outside (@pxref{@code{@@verbatim}}). Starting any environment inside a macro and ending it outside may or may not work, for that matter. @item Macros that completely define macros are ok, but it's not possible to have incompletely nested macro definitions. That is, @code{@@macro} and @code{@@end macro} (likewise for @code{@@rmacro}) must be correctly paired. For example, you cannot start a macro definition within a macro, and then end that nested definition outside the macro. @end itemize @c Texinfo 5.0 released in 2013 In the @command{makeinfo} implementation before Texinfo 5.0, ends of lines from expansion of a @code{@@macro} definition did not end an @@-command line-delimited argument (@code{@@chapter}, @code{@@center}, etc.). This is no longer the case. For example: @example @@macro twolines@{@} aaa bbb @@end macro @@center @@twolines@{@} @end example In the current @code{texi2any}, this is equivalent to: @example @@center aaa bbb @end example @noindent with just @samp{aaa} as the argument to @code{@@center}. In the earlier implementation, it would have been parsed as this: @example @@center aaa bbb @end example @node @code{@@alias} @nodedescription Command aliases. @section @samp{@@alias @var{new}=@var{existing}} @anchor{alias}@c old name @cindex Aliases, command @cindex Command aliases @findex alias The @samp{@@alias} command defines a new command to be just like an existing one. This is useful for defining additional markup names, thus preserving additional semantic information in the input even though the output result may be the same. Write the @samp{@@alias} command on a line by itself, followed by the new command name, an equals sign, and the existing command name. Whitespace around the equals sign is optional and ignored if present. Thus: @example @@alias @var{new} = @var{existing} @end example For example, if your document contains citations for both books and some other media (movies, for example), you might like to define a macro @code{@@moviecite@{@}} that does the same thing as an ordinary @code{@@cite@{@}} but conveys the extra semantic information as well. You'd do this as follows: @example @@alias moviecite = cite @end example Macros do not always have the same effect as aliases, due to vagaries of argument parsing. Also, aliases are much simpler to define than macros. So the command is not redundant. Unfortunately, it's not possible to alias Texinfo environments; for example, @code{@@alias lang=example} is an error. Aliases must not be recursive, directly or indirectly. It is not advisable to redefine any @TeX{} primitive, plain @TeX{}, or Texinfo command name as an alias. Unfortunately this is a very large set of names, and the possible resulting errors from @TeX{} are unpredictable. Alias identifiers should be the same as for macro names, that is alphanumerics and (except as the first character) @samp{-}. However, with @TeX{}, letters only should be used. So, we recommend using only letters. @node Line Macros @nodedescription Macros using whole line for arguments. @section Line Macros @findex linemacro @cindex Line macros @cindex Macros taking whole line as an argument You can also define a macro using the @samp{@@linemacro} command. The syntax for line macro definitions is similar to that for @code{@@macro}. However, the syntax for using a macro defined this way is different. The macro call uses the rest of the line, with arguments separated by spaces. The line macro facility is mainly intended to allow you to define commands that operate similarly to the builtin commands for providing definitions (@pxref{Definition Commands}). For example: @example @@linemacro defbuiltin @{name, args@} @@defline @{Builtin@} \name\ \args\ @@end linemacro @end example The above macro may be used as @example @@defblock @@defbuiltin foo (bar) Explanation @@end defblock @end example This produces the following result: @linemacro defbuiltin {name, args} @defline {Builtin} \name\ \args\ @end linemacro @defblock @defbuiltin foo (bar) Explanation @end defblock Here the first argument is @samp{foo}, and is substituted where @samp{\name\} appears in the macro body. Likewise, @samp{(bar)} is substituted for @samp{\args\}. You can include spaces in a macro argument by surrounding the argument by braces. Any pair of braces enclosing an argument is removed before substitution. Any empty arguments (including the last one) must be given as @samp{@{@}}. Additionally, non-initial spaces may appear in the final argument in the argument list without surrounding braces (as in the example below). If an argument line for a line macro ends in a @samp{@@} character, then this character together with the following newline are included in a macro argument, and the following line in the input file is also used to get the arguments for the macro. Note that any substitution of the @samp{@@@var{<newline>}} sequence must be in a valid context, such as a definition line (@pxref{Def Cmd Continuation Lines}). Another example: @example @@linemacro deffunc @{type, name, args@} @@findex \name\ @@deftypeline @{Func@} @{\type\@} \name\ \args\ @@end linemacro @@defblock @@deffunc @{long int@} F (int @@var@{one@}, int @@var@{two@}, @@ int @@var@{three@}, int @@var@{four@}, int @@var@{five@}) Explanation @@end defblock @end example @noindent Note how braces are needed around @samp{\type\} in the macro body in case the @code{type} argument contains a space. This example produces the output below and enters an index entry for @code{F}. @linemacro deffunc {type, name, args} @c @findex \name\ @deftypeline {Func} {\type\} \name\ \args\ @end linemacro @defblock @deffunc {long int} F (int @var{one}, int @var{two}, @ int @var{three}, int @var{four}, int @var{five}) Explanation @end defblock Line macros produce a whole number of lines of output in their expansion. There may be better compatibility between the Texinfo processors (@command{texi2any} and @TeX{} with @file{texinfo.tex}) for macros defined with @code{@@linemacro} than for those defined with @code{@@macro}. @node @code{@@definfoenclose} @nodedescription Customized highlighting. @section @code{@@definfoenclose}: Customized Highlighting @anchor{definfoenclose}@c old name @cindex Highlighting, customized @findex definfoenclose An @code{@@definfoenclose} command may be used to define a highlighting command for online output formats. A command defined using @code{@@definfoenclose} marks text by enclosing it in strings that precede and follow the text. In practice, there is little use for this command, and we do not recommend you use it. Support for @code{@@definfoenclose} may be removed in future releases of Texinfo. Write a @code{@@definfoenclose} command at the beginning of a line followed by three comma-separated arguments. The first argument to @code{@@definfoenclose} is the @@-command name (without the @code{@@}); the second argument is the start delimiter string; and the third argument is the end delimiter string. The latter two arguments enclose the highlighted text in the output. A delimiter string may contain spaces. Neither the start nor end delimiter is required. If you do not want a start delimiter but do want an end delimiter, you must follow the command name with two commas in a row; otherwise, the end delimiter string you intended will naturally be (mis)interpreted as the start delimiter string. An enclosure command defined this way takes one argument in braces, since it is intended for new markup commands (@pxref{Marking Text}). @findex phoo For example, you can write: @example @@definfoenclose phoo,//,\\ @end example @noindent near the beginning of a Texinfo file to define @code{@@phoo} as an Info and HTML formatting command that inserts `//' before and `\\' after the argument to @code{@@phoo}. You can then write @code{@@phoo@{bar@}} wherever you want `//bar\\' highlighted in Info and HTML. For @TeX{} formatting, you could write @example @@iftex @@alias phoo = i @@end iftex @end example @noindent to define @code{@@phoo} as a command that causes @TeX{} to typeset the argument to @code{@@phoo} in italics. Each definition applies to its own formatter: one for @TeX{}, the other for online formats. The @TeX{} definitions need to be in @samp{@@iftex}. @code{@@definfoenclose} command need not be within @samp{@@ifinfo} unless you want to use different definitions for different online output formats. @code{@@definfoenclose} defined commands have no effect in DocBook and @LaTeX{} output, their argument is output as-is. An @code{@@alias} could also be used for these formats. @code{@@definfoenclose} definitions must not be recursive, directly or indirectly. @node External Macro Processors @nodedescription @code{#line} directives. @section External Macro Processors: Line Directives @cindex External macro processors @cindex Macro processors, external Texinfo macros (and its other text substitution facilities) work fine in straightforward cases. If your document needs unusually complex processing, however, their fragility and limitations can be a problem. In this case, you may want to use a different macro processor altogether, such as M4 (@pxref{Top,,, m4, M4}) or CPP (@pxref{Top,,, cpp, The C Preprocessor}). With one exception, Texinfo does not need to know whether its input is ``original'' source or preprocessed from some other source file. Therefore, you can arrange your build system to invoke whatever programs you like to handle macro expansion or other preprocessing needs. Texinfo does not offer built-in support for any particular preprocessor, since no one program seemed likely to suffice for the requirements of all documents. @cindex Line numbers, in error messages @cindex Error messages, line numbers in The one exception is line numbers in error messages. In that case, the line number should refer to the original source file, whatever it may be. There's a well-known mechanism for this: the so-called @samp{#line} directive. Texinfo supports this. @node @samp{#line} Directive @subsection @samp{#line} Directive @cindex @samp{#line} directive An input line such as this: @example @hashchar{}line 100 "foo.ptexi" @end example @noindent indicates that the next line was line 100 of the file @file{foo.ptexi}, and so that's what an error message should refer to. Both M4 (@pxref{Preprocessor features,,, m4, GNU M4}) and CPP (@pxref{Line Control,,, cpp, The C Preprocessor}, and @ref{Preprocessor Output,,, cpp, The C Preprocessor}) can generate such lines. The @command{texi2any} program recognizes these lines by default, except within @code{@@verbatim} blocks (@pxref{@code{@@verbatim}}). Their recognition can be turned off completely with @code{CPP_LINE_DIRECTIVES} (@pxref{Other Customization Variables}), though there is normally no reason to do so. For those few programs (M4, CPP, Texinfo) which need to document @samp{#line} directives and therefore have examples which would otherwise match the pattern, the command @code{@@hashchar@{@}} can be used (@pxref{Inserting a Hashsign}). The example line above looks like this in the source for this manual: @example @@hashchar@{@}line 100 "foo.ptexi" @end example The @code{@@hashchar} command was added to Texinfo in 2013. If you don't want to rely on it, you can also use @code{@@set} and @code{@@value} to insert the literal @samp{#}: @example @@set hash # @@value@{hash@}line 1 "example.c" @end example Or, if suitable, a @code{@@verbatim} environment can be used instead of @code{@@example}. As mentioned above, @code{#line}-recognition is disabled inside verbatim blocks. @node @samp{#line} and @TeX{} @subsection @samp{#line} and @TeX{} @cindex @TeX{} and @samp{#line} directives @cindex @samp{#line} directive @subentry not processing with @TeX{} As mentioned, @command{texi2any} recognizes the @samp{#line} directives described in the previous section. However, @file{texinfo.tex} does not and cannot. Therefore, such a line will be incorrectly typeset verbatim if @TeX{} sees it. The solution is to use @command{texi2any}'s macro expansion options before running @TeX{}. There are three approaches: @itemize @bullet @item If you run @command{texi2dvi} or its variants (@pxref{Format with @command{texi2dvi}}), you can pass @option{-E} and @command{texi2dvi} will run @command{texi2any} first to expand macros and eliminate @samp{#line}. @item If you run @command{texi2any}, you can specify @option{--no-ifinfo --iftex -E somefile.out}, and then give @file{somefile.out} to @command{texi2dvi} in a separate command. @item Or you can run @option{texi2any --dvi --Xopt -E}. (Or @option{--pdf} instead of @option{--dvi}.) @command{texi2any} will then call @command{texi2dvi -E}. @end itemize @findex errormsg@r{, and line numbers in @TeX{}} One last caveat regarding use with @TeX{}: since the @code{#line} directives are not recognized, the line numbers emitted by the @code{@@errormsg@{@}} command (@pxref{Conditional Commands}), or by @TeX{} itself, are the (incorrect) line numbers from the derived file which @TeX{} is reading, rather than the preprocessor-specified line numbers. @node @samp{#line} Syntax Details @subsection @samp{#line} Syntax Details @cindex @samp{#line} directive @subentry syntax details @cindex Syntax details, @samp{#line} @cindex Regular expression, for @samp{#line} Syntax details for the @samp{#line} directive: the @samp{#} character can be preceded or followed by whitespace, the word @samp{line} is optional, and the file name can be followed by a whitespace-separated list of integers (these are so-called ``flags'' output by CPP in some cases). For those who like to know the gory details, the actual (Perl) regular expression which is matched is this: @example /^\s*#\s*(line)? (\d+)(( "([^"]+)")(\s+\d+)*)?\s*$/ @end example As far as we've been able to tell, the trailing integer flags only occur in conjunction with a file name, so that is reflected in the regular expression. As an example, the following is a syntactically valid @samp{#line} directive, meaning line 1 of @file{/usr/include/stdio.h}: @example @hashchar{} 1 "/usr/include/stdio.h" 2 3 4 @end example Unfortunately, the quoted file name (@samp{"..."}) has to be optional, because M4 (especially) can often generate @samp{#line} directives within a single file. Since the @samp{line} is also optional, the result is that lines might match which you wouldn't expect, e.g., @example @hashchar{} 1 @end example The possible solutions are described above (@pxref{@samp{#line} Directive}). @node Include Files @nodedescription How to incorporate other Texinfo files. @chapter Include Files @cindex Include files When a Texinfo processor sees an @code{@@include} command in a Texinfo file, it processes the contents of the file named by the @code{@@include} and incorporates them into the output files being created. Include files thus let you keep a single large document as a collection of conveniently small parts. @node Using Include Files @nodedescription How to use the @code{@@include} command. @section How to Use Include Files @findex include To include another file within a Texinfo file, write the @code{@@include} command at the beginning of a line and follow it on the same line by the name of a file to be included. For example: @example @@include buffers.texi @end example @code{@@value@{@var{var}@}} references are expanded on the @code{@@include} line. Other than that, the only @@-commands allowed are @code{@@@@}, @code{@@@{}, @code{@@@}} and associated @@-commands such as @code{@@atchar@{@}}. An included file should simply be a segment of text that you expect to be included as is into the overall or @dfn{outer} Texinfo file; it should not contain the standard beginning and end parts of a Texinfo file. In particular, you should not start an included file with a line saying @samp{\input texinfo}; if you do, that text is inserted into the output file literally. Likewise, you should not end an included file with a @code{@@bye} command; nothing after @code{@@bye} is formatted. In the long-ago past, you were required to write an @code{@@setfilename} line at the beginning of an included file, but no longer. Now, it does not matter whether you write such a line. If an @code{@@setfilename} line exists in an included file, it is ignored. GNU Emacs Texinfo mode provides @code{texinfo-multiple-files-update} to update node pointers and master menu with multiple include files. @xref{Update Multiple Files}. @node Sample Include File @nodedescription A sample outer file with included files within it; and a sample included file. @section Sample File with @code{@@include} @cindex Sample @code{@@include} file @cindex Include file sample @cindex @code{@@include} file sample Here is an example of an outer Texinfo file with @code{@@include} files within it: @example @group \input texinfo @@c -*-texinfo-*- @@settitle Include Example @end group @group @@node Top @@top Include Example @end group @group @@include foo.texi @@include bar.texi @@include concept-index.texi @@bye @end group @end example An included file, such as @file{foo.texi}, might look like this: @example @group @@node First @@chapter First Chapter Contents of first chapter @dots{} @end group @end example The full contents of @file{concept-index.texi} might be as simple as this: @example @group @@node Concept Index @@unnumbered Concept Index @@printindex cp @end group @end example @c FIXME not sure that this is of general interest for Texinfo The outer Texinfo source file for @cite{The GNU Emacs Lisp Reference Manual} is named @file{elisp.texi}. This outer file has already contained a master menu with 417 entries and a list of 41 @code{@@include} files. @node @code{@@verbatiminclude} @nodedescription Including a file verbatim. @section @code{@@verbatiminclude} @var{file}: Include a File Verbatim @anchor{verbatiminclude}@c old name @findex verbatiminclude @cindex Verbatim, include file @cindex Including a file verbatim You can include the exact contents of a file in the document with the @code{@@verbatiminclude} command: @example @@verbatiminclude @var{filename} @end example The contents of @var{filename} is printed in a verbatim environment (@pxref{@code{@@verbatim}}). Generally, the file is printed exactly as it is, with all special characters and white space retained. No indentation is added; if you want indentation, enclose the @code{@@verbatiminclude} within @code{@@example} (@pxref{@code{@@example}}). @code{@@value@{@var{var}@}} references are expanded on the @code{@@verbatiminclude} line. This makes it possible to include files in other directories within a distribution, for instance: @example @@verbatiminclude @@value@{top_srcdir@}/NEWS @end example @noindent (You still have to get @code{top_srcdir} defined in the first place.) Other than that, the only @@-commands allowed are @code{@@@@}, @code{@@@{}, @code{@@@}} and associated @@-commands such as @code{@@atchar@{@}}. For a method on printing the file contents in a smaller font size, see the end of the section on @code{@@verbatim}. @ignore @node Include Files Evolution @section Evolution of Include Files When Info was first created, it was customary to create many small Info files on one subject. Each Info file was formatted from its own Texinfo source file. This custom meant that Emacs did not need to make a large buffer to hold the whole of a large Info file when someone wanted information; instead, Emacs allocated just enough memory for the small Info file that contained the particular information sought. This way, Emacs could avoid wasting memory. References from one file to another were made by referring to the file name as well as the node name. (@xref{Other Info Files, , Referring to Other Info Files}. Also, see @ref{Four and Five Arguments, , @code{@@xref} with Four and Five Arguments}.) Include files were designed primarily as a way to create a single, large printed manual out of several smaller Info files. In a printed manual, all the references were within the same document, so @TeX{} could automatically determine the references' page numbers. The Info formatting commands used include files only for creating joint indices; each of the individual Texinfo files had to be formatted for Info individually. (Each, therefore, required its own @code{@@setfilename} line.) However, because large Info files are now split automatically, it is no longer necessary to keep them small. Nowadays, multiple Texinfo files are used mostly for large documents, such as @cite{The GNU Emacs Lisp Reference Manual}, and for projects in which several different people write different sections of a document simultaneously. In addition, the Info formatting commands have been extended to work with the @code{@@include} command so as to create a single large Info file that is split into smaller files if necessary. This means that you can write menus and cross-references without naming the different Texinfo files. @end ignore @node Hardcopy with @TeX{} @nodedescription Output for paper, with @TeX{}. @chapter Formatting and Printing with @TeX{} @anchor{Hardcopy} @c old name @anchor{Printing} @cindex Format and print hardcopy @cindex Printing hardcopy @cindex Hardcopy, printing it @cindex Making a printed manual @cindex Sorting indices @cindex Indices, sorting @cindex @TeX{} index sorting Running the @command{texi2dvi} or @command{texi2pdf} command is the simplest way to create printable output. These commands are installed as part of the Texinfo package. In more detail, typesetting and printing a Texinfo file is a multi-step process in which you use the @TeX{} program to create a file for printing (called a DVI or PDF file), and then print the file. Optionally, you may also create indices using the @command{texindex} command after first running @TeX{}; and then you must run @TeX{} again. @command{texi2dvi} takes care of all of this, running @TeX{} and @command{texindex} as needed (@pxref{Format with @command{texi2dvi}}). @anchor{Within Emacs} @c old node name @anchor{Emacs Shell Printing} @c old node name @cindex Print, format from Emacs shell @cindex Format, print from Emacs shell @cindex Shell, format, print from @cindex Emacs shell, format, print from @cindex GNU Emacs shell, format, print from When you use the shell commands, you can either work directly in the operating system shell or work within a shell inside GNU Emacs (or some other computing environment). You can give formatting and printing commands from a shell within GNU Emacs, just like any other shell command. To create a shell within Emacs, type @kbd{M-x shell} (@pxref{Shell,,, emacs, The GNU Emacs Manual}). If you are using GNU Emacs, you can also use commands provided by Texinfo mode instead of shell commands. @xref{Printing with Emacs}. For specifing details of the printed output such as paper size, see @ref{Global Document Commands}. @node Use @TeX{} @nodedescription Use @TeX{} to format for hardcopy. @section Use @TeX{} The typesetting program called @TeX{} is used to format a Texinfo document for printable output. @TeX{} is a very powerful typesetting program and, when used correctly, does an exceptionally good job. It is not included in the Texinfo package, being a vast suite of software in itself. @anchor{Obtaining @TeX{}} @cindex Obtaining @TeX{} @cindex @TeX{}, how to obtain @TeX{} is a document formatter that is used by the FSF for its documentation. It is the easiest way to get printed output (e.g., PDF and PostScript) for Texinfo manuals. TeX is freely redistributable, and you can get it over the Internet or on physical media. See @url{http://tug.org/texlive}. @c please keep that text in sync with www.gnu.org/prep/FTP @node Format with @command{texi2dvi} or @command{texi2pdf} @nodedescription The simplest way to format. @section Format with @command{texi2dvi} or @command{texi2pdf} @c previously in a separate node. To be used when referring @c only to PDF output, as is the case in @direntry @anchor{PDF Output} @c To be used when referring to DVI output or to texi2dvi only, @c as is the case in @direntry @anchor{Format with @command{texi2dvi}} @pindex texi2dvi @r{(shell script)} @pindex texi2pdf @r{(shell script)} @cindex DVI, output in @cindex PDF output @cindex Output, in PDF The @command{texi2dvi} program takes care of all the steps for producing a @TeX{} DVI file from a Texinfo document. Similarly, @command{texi2pdf} produces a PDF file@footnote{@dfn{PDF} stands for `Portable Document Format'. It was invented by Adobe Systems for document interchange, based on their PostScript language.}. To run @command{texi2dvi} or @command{texi2pdf} on an input file @file{foo.texi}, do this (where @samp{prompt$ } is your shell prompt): @example prompt$ @kbd{texi2dvi foo.texi} prompt$ @kbd{texi2pdf foo.texi} @end example As shown in this example, the file names given to @command{texi2dvi} and @command{texi2pdf} must include any extension, such as @samp{.texi}. For a list of all the options, run @samp{texi2dvi --help}. Some of the options are discussed below. @opindex --pdf@r{, for @command{texi2dvi}} @pindex pdftexi2dvi With the @option{--pdf} option, @command{texi2dvi} produces PDF output instead of DVI, by running @command{pdftex} instead of @command{tex}. Alternatively, the command @command{texi2pdf} is an abbreviation for running @samp{texi2dvi --pdf}. The command @command{pdftexi2dvi} is also provided as a convenience for AUC-@TeX{} (@pxref{Top,,, auctex, AUC-@TeX{}}), as it prefers to merely prepend @samp{pdf} to DVI producing tools to have PDF producing tools. @opindex --dvipdf@r{, for @command{texi2dvi}} @pindex dvipdfmx With the @option{--dvipdf} option, @command{texi2dvi} produces PDF output by running @TeX{} and then a DVI-to-PDF program: if the @env{DVIPDF} environment variable is set, that value is used, else the first program extant among @code{dvipdfmx}, @code{dvipdfm}, @code{dvipdf}, @code{dvi2pdf}, @code{dvitopdf}. This method generally supports CJK typesetting better than @command{pdftex}. @opindex --ps@r{, for @command{texi2dvi}} @pindex dvips With the @option{--ps} option, @command{texi2dvi} produces PostScript instead of DVI, by running @command{tex} and then @command{dvips} (@pxref{Top,,, dvips, Dvips}). (Or the value of the @env{DVIPS} environment variable, if set.) @opindex --language@r{, for @command{texi2dvi}} @cindex @LaTeX{}, processing with @command{texi2dvi} @command{texi2dvi} can also be used to process @LaTeX{} files. Normally @command{texi2dvi} is able to guess the input file language by its contents and file name extension; however, if it guesses wrong you can explicitly specify the input language using @option{--language=@var{lang}} command line option, where @var{lang} is either @samp{latex} or @samp{texinfo}. @opindex --command@r{, for @command{texi2dvi}} One useful option to @command{texi2dvi} is @samp{--command=@var{cmd}}. This inserts @var{cmd} on a line by itself at the start of the file in a temporary copy of the input file, before running @TeX{}. With this, you can specify different printing formats, such as @code{@@smallbook} (@pxref{@code{@@smallbook}}), @code{@@afourpaper} (@pxref{A4 Paper}), or @code{@@pagesizes} (@pxref{@code{@@pagesizes}}), without actually changing the document source. (You can also do this on a site-wide basis with @file{texinfo.cnf}; @pxref{Preparing for @TeX{}}). The option @option{-E} (equivalently, @option{-e} and @option{--expand}) does Texinfo macro expansion using @command{texi2any} instead of the @TeX{} implementation (@pxref{Macro Details}). Each implementation has its own limitations and advantages. @command{texi2dvi} takes the @option{--build=@var{mode}} option to specify where the @TeX{} compilation takes place, and, as a consequence, how auxiliary files are treated. The build mode can also be set using the environment variable @env{TEXI2DVI_BUILD_MODE}. The valid values for @var{mode} are: @table @samp @item local Compile in the current directory, leaving all the auxiliary files around. This is the traditional TeX use. @item tidy Compile in a local @code{*.t2d} directory, where the auxiliary files are left. Output files are copied back to the original file. Using the @samp{tidy} mode brings several advantages: @itemize - @item the current directory is not cluttered with plethora of temporary files. @item clutter can be even further reduced using @option{--build-dir=dir}: all the @code{*.t2d} directories are stored there. @item clutter can be reduced to zero using, e.g., @option{--build-dir=/tmp/\$USER.t2d} or @option{--build-dir=\$HOME/.t2d}. @item the output file is updated after every successful @TeX{} run, for sake of concurrent visualization of the output. In a @samp{local} build the viewer stops during the whole @TeX{} run. @item if the compilation fails, the previous state of the output file is preserved. @item @acronym{PDF} and @acronym{DVI} compilation are kept in separate subdirectories preventing any possibility of auxiliary file incompatibility. @end itemize On the other hand, because @samp{tidy} compilation takes place in another directory, occasionally @TeX{} won't be able to find some files (e.g., when using @code{\graphicspath}): in that case, use @option{-I} to specify the additional directories to consider. @item clean Same as @samp{tidy}, but remove the auxiliary directory afterwards. Every compilation therefore requires the full cycle. @end table @pindex etex @command{texi2dvi} will use @command{etex} if it is available, because it runs faster in some cases, and provides additional tracing information when debugging @file{texinfo.tex}. Nevertheless, this extended version of @TeX{} is not required, and the DVI output is identical. @cindex file recorder for @TeX{} @cindex @samp{\openout} line in log file @command{texi2dvi} attempts to detect auxiliary files output by @TeX{}, either by using the @option{-recorder} option, or by scanning for @samp{\openout} in the log file that a run of @TeX{} produces. You may control how @command{texi2dvi} does this with the @env{TEXI2DVI_USE_RECORDER} environment variable. Valid values are: @table @samp @item yes use the @option{-recorder} option, no checks. @item no scan for @samp{\openout} in the log file, no checks. @item yesmaybe check whether @option{-recorder} option is supported, and if yes use it, otherwise check for tracing @samp{\openout} in the log file is supported, and if yes use it, else it is an error. @item nomaybe same as @samp{yesmaybe}, except that the @samp{\openout} trace in log file is checked first. @end table The default is @samp{nomaybe}. This environment variable is provided for troubleshooting purposes, and may change or disappear in the future. @node Format with @command{tex}/@command{texindex} @nodedescription Formatting with explicit shell commands. @section Format with @command{tex}/@command{texindex} @cindex Shell formatting with @command{tex} and @command{texindex} @cindex Formatting with @command{tex} and @command{texindex} @cindex DVI file You can do the basic formatting of a Texinfo file with the shell command @command{tex} followed by the name of the Texinfo file. For example: @example tex foo.texi @end example @noindent @TeX{} will produce a @dfn{DVI file} as well as several auxiliary files containing information for indices, cross-references, etc. The DVI file (for @dfn{DeVice Independent} file) can be printed on virtually any device, perhaps after a further conversion (see the previous section). @pindex texindex The @command{tex} formatting command itself does not sort the indices; it writes an output file of unsorted index data. To generate a printed index after running the @command{tex} command, you first need a sorted index to work from. The @command{texindex} command sorts indices. (@command{texi2dvi}, described in the previous section, runs @command{tex} and @command{texindex} as necessary.) @anchor{Names of index files} @cindex Names of index files @cindex Index file names @command{tex} outputs unsorted index files under names following a standard convention: the name of your main input file with any @samp{.texi} or similar extension replaced by the two letter index name. For example, the raw index output files for the input file @file{foo.texi} would be, by default, @file{foo.cp}, @file{foo.vr}, @file{foo.fn}, @file{foo.tp}, @file{foo.pg} and @file{foo.ky}. Those are exactly the arguments to give to @command{texindex}. @need 1000 @cindex Wildcards @cindex Globbing Instead of specifying all the unsorted index file names explicitly, it's typical to use @samp{??} as shell wildcards and give the command in this form: @example texindex foo.?? @end example @noindent This command will run @command{texindex} on all the unsorted index files, including any two letter indices that you have defined yourself using @code{@@defindex} or @code{@@defcodeindex}. You can safely run @samp{texindex foo.??} even if there are files with two letter extensions that are not index files, such as @samp{foo.el}. The @command{texindex} command reports but otherwise ignores such files. For each file specified, @command{texindex} generates a sorted index file whose name is made by appending @samp{s} to the input file name; for example, @file{foo.cps} is made from @file{foo.cp}. The @code{@@printindex} command looks for a file with that name (@pxref{Printing Indices & Menus}). @TeX{} does not read the raw index output file, and @command{texindex} does not alter it. After you have sorted the indices, you need to rerun @command{tex} on the Texinfo file. This regenerates the output file, this time with up-to-date index entries. Finally, you may need to run @command{tex} one more time, to get the page numbers in the cross-references correct. To summarize, this is a five-step process. (Alternatively, it's a one-step process: run @command{texi2dvi}; see the previous section.) @enumerate @item Run @command{tex} on your Texinfo file. This generates a DVI file (with undefined cross-references and no indices), and the raw index files (with two letter extensions). @item Run @command{texindex} on the raw index files. This creates the corresponding sorted index files (with three letter extensions). @item Run @command{tex} again on your Texinfo file. This regenerates the DVI file, this time with indices and defined cross-references, but with page numbers for the cross-references from the previous run, generally incorrect. @item Sort the indices again, with @command{texindex}. @item Run @command{tex} one last time. This time the correct page numbers are written for the cross-references. @end enumerate @pindex pdftex To generate PDF, you can run the @command{pdftex} program instead of plain @command{tex}. That is, run @command{pdftex foo.texi} instead of @samp{tex foo.texi} in the examples above. @node Formatting Partial Documents @subsection Formatting Partial Documents @cindex Formatting partial documents @cindex Partial documents, formatting @cindex Chapters, formatting one at a time @cindex Auxiliary files, omitting @cindex Pointer validation @subentry suppressing @findex novalidate Sometimes you may wish to print a document while you know it is incomplete, or to print just one chapter of a document. In such a case, the usual auxiliary files that @TeX{} creates and warnings @TeX{} gives about undefined cross-references are just nuisances. You can avoid them with the @code{@@novalidate} command, which you must give @emph{before} any sectioning or cross-reference commands. Thus, the beginning of your file would look approximately like this: @example \input texinfo @@novalidate @dots{} @end example @noindent @code{@@novalidate} also turns off validation in @command{texi2any}, just like its @code{--no-validate} option (@pxref{Invoking @command{texi2any}}). Furthermore, you need not run @command{texindex} each time after you run @command{tex}. The @command{tex} formatting command simply uses whatever sorted index files happen to exist from a previous use of @command{texindex}. If those are out of date, that is usually ok while you are creating or debugging a document. @node Details of @command{texindex} @subsection Details of @command{texindex} @cindex Braces, in index entries In Texinfo version 6, released in 2015, the @command{texindex} program was completely reimplemented. The principal functional difference is that index entries beginning with a left brace or right brace (@samp{@{} resp.@: @samp{@}}) can work properly. For example, these simple index entries are processed correctly, including the ``index initial'' shown in the index: @example @@cindex @@@{ @@cindex @@@} ... @@printindex cp @end example @cindex Literate programming, with Texinfo and @command{awk} @cindex Texinfo, and literate programming @cindex Robbins, Arnold @pindex texiwebjr @pindex ti.twjr Although not a matter of functionality, readers may be interested to know that the new @command{texindex} is a literate program (@url{https://en.wikipedia.org/wiki/Literate_programming}) using Texinfo for documentation and (portable) @command{awk} for code. A single source file, @file{texindex/ti.twjr} in this case, produces the runnable program, a printable document, and an online document. The system is called TexiWeb Jr.@: and was created by Arnold Robbins, who also wrote the new @command{texindex}. Not coincidentally, he is also the long-time maintainer of @command{gawk} (GNU Awk, @pxref{Top,,, gawk, The GNU Awk User's Guide}). The file @file{texindex/Makefile.am} shows example usage of the system. @node Print with @command{lpr} @nodedescription How to print. @section Print with @command{lpr} from Shell @pindex lpr @r{(DVI print command)} The way to print a DVI file depends on your system installation. Two common ones are @samp{dvips foo.dvi -o} to make a PostScript file first and then print that, and @samp{lpr -d foo.dvi} to print a DVI file directly. For example, the following commands will (probably) suffice to sort the indices, format, and print this manual using the @command{texi2dvi} shell script (@pxref{Format with @command{texi2dvi}}). @example @group texi2dvi texinfo.texi dvips texinfo.dvi -o lpr texinfo.ps @end group @end example Depending on the @command{lpr} setup on your machine, you might be able to combine the last two steps into @code{lpr -d texinfo.dvi}. @cindex PCL file, for printing You can also generate a PDF file by running @command{texi2dvi} instead of @command{texi2dvi}; a PDF is often directly printable. Or you can generate a PCL file by using @command{dvilj} instead of @command{dvips}, if you have a printer that prefers that format. @cindex Shell printing, on MS-DOS/MS-Windows @cindex Printing DVI files, on MS-DOS/MS-Windows @pindex lpr@r{-d, replacements on MS-DOS/MS-Windows} @command{lpr} is a standard program on Unix systems, but it is usually absent on MS-DOS/MS-Windows. If so, just create a PostScript or PDF or PCL file, whatever is most convenient, and print that in the usual way for your machine (e.g., by sending to the appropriate port, usually @samp{PRN}). @node Preparing for @TeX{} @nodedescription What to do before you use @TeX{}. @section Preparing for @TeX{} @cindex Preparing for @TeX{} @cindex @TeX{} input initialization @cindex @sortas{profile init} @file{.profile} initialization file @cindex @sortas{cshrc init} @file{.cshrc} initialization file @cindex Initialization file for @TeX{} input @TeX{} needs to find the @file{texinfo.tex} file that the @samp{\input texinfo} command on the first line reads. The @file{texinfo.tex} file tells @TeX{} how to handle @@-commands; it is included in all standard GNU distributions. The latest version released for general use is available from the usual GNU servers and mirrors: @display @uref{http://ftp.gnu.org/gnu/texinfo/texinfo.tex} @uref{http://ftpmirror.gnu.org/texinfo/texinfo.tex} @end display The latest development version is available from the Texinfo source repository: @display @uref{http://git.savannah.gnu.org/cgit/texinfo.git/plain/doc/texinfo.tex} @end display @pindex texinfo.tex@r{, installing} @file{texinfo.tex} is essentially a standalone file, so, if you need or want to try a newer version than came with your system, it nearly always suffices to download it and put it anywhere that @TeX{} will find it. You can replace any existing @file{texinfo.tex} with a newer version (of course saving the original in case of disaster). @pindex epsf.tex@r{, installing} Also, you should install @file{epsf.tex}, if it is not already installed from another distribution. More details are at the end of the description of the @code{@@image} command (@pxref{Images}). @cindex European Computer Modern fonts @subentry installing @cindex EC fonts, installing @cindex CM-Super fonts @subentry installing To use quotation marks other than those used in English, you'll need to have the European Computer Modern fonts (e.g., @file{ecrm1000}) and (for PDF output) CM-Super fonts (@pxref{Inserting Quotation Marks}). @cindex @code{feymr10} @subentry installing @cindex Euro font, installing To use the @code{@@euro} command, you'll need the @samp{feym*} fonts (e.g., @file{feymr10}). @xref{@code{@@euro}}. All of the above files should be installed by default in a reasonable @TeX{} installation. @pindex texinfo.cnf @r{installation} @cindex Customizing of @TeX{} for Texinfo @cindex Site-wide Texinfo configuration file Optionally, you may create a file @file{texinfo.cnf} for site configuration. When processing a Texinfo file, @TeX{} looks for this file in its search path, which includes the current directory and standard installation directories. You can use this file for local conventions. For example, if @file{texinfo.cnf} contains the line @samp{@@afourpaper} (@pxref{A4 Paper}), then all Texinfo documents will be processed with that page size in effect. If you have nothing to put in @file{texinfo.cnf}, you do not need to create it. @cindex Environment variable @code{TEXINPUTS} @vindex TEXINPUTS You can set the @code{TEXINPUTS} environment variable to allow @TeX{} to find @file{texinfo.cnf}. (This also works for @file{texinfo.tex} and any other file @TeX{} might read). For example, if you are using a Bourne shell-compatible shell (@code{sh}, @code{bash}, @code{ksh}, @dots{}), your @file{.profile} file could contain the lines: @example TEXINPUTS=.:/home/me/mylib: export TEXINPUTS @end example @noindent These settings would cause @TeX{} first to look for an @file{\input} file in the current directory, indicated by the @samp{.}, then in a hypothetical user @samp{me}'s @file{mylib} directory, and finally in the system directories. (A leading, trailing, or doubled @samp{:} indicates searching the system directories at that point.) @node Overfull hboxes @nodedescription What are and what to do with overfull hboxes. @section Overfull ``hboxes'' @cindex Overfull @samp{hboxes} @cindex @samp{hbox}, overfull @cindex Final output @TeX{} is sometimes unable to typeset a line within the normal margins. This most often occurs when @TeX{} comes upon what it interprets as a long word that it cannot hyphenate, such as an electronic mail network address or a very long identifier. When this happens, @TeX{} prints an error message like this: @example Overfull @@hbox (20.76302pt too wide) @end example @findex hbox @noindent (In @TeX{}, lines are in ``horizontal boxes'', hence the term, ``hbox''. @samp{@@hbox} is a @TeX{} primitive not used in the Texinfo language.) @TeX{} also provides the line number in the Texinfo source file and the text of the offending line, which is marked at all the places that @TeX{} considered hyphenation. @xref{Debugging with @TeX{}}, for more information about typesetting errors. If the Texinfo file has an overfull hbox, you can rewrite the sentence so the overfull hbox does not occur, or you can decide to leave it. A small excursion into the right margin often does not matter and may not even be noticeable. If you have many overfull boxes and/or an antipathy to rewriting, you can coerce @TeX{} into greatly increasing the allowable interword spacing, thus (if you're lucky) avoiding many of the bad line breaks, like this: @findex \emergencystretch @example @@tex \global\emergencystretch = .9\hsize @@end tex @end example @noindent (You should adjust the fraction as needed.) This huge value for @code{\emergencystretch} cannot be the default, since then the typeset output would generally be of noticeably lower quality; its default value is @samp{.15\hsize}. @code{\hsize} is the @TeX{} dimension containing the current line width. @cindex Black rectangle in hardcopy @cindex Rectangle, black in hardcopy @cindex Box, ugly black in hardcopy @cindex Ugly black rectangles in hardcopy For any overfull boxes you do have, @TeX{} will print a large, ugly, black rectangle beside the line that contains the overfull hbox unless told otherwise. This is so you will notice the location of the problem if you are correcting a draft. @findex finalout To prevent such a monstrosity from marring your final printout, write the following in the beginning of the Texinfo file on a line of its own, before the @code{@@titlepage} command: @example @@finalout @end example @node Generic Translator @command{texi2any} @nodedescription @command{texi2any}, an all-purpose converter. @chapter @command{texi2any}: The Translator for Texinfo @command{texi2any} is the generic translator for Texinfo that can produce different output formats and is highly customizable. It supports these formats: @display Info (by default, or with @option{--info}), HTML (with @option{--html}), EPUB 3 (with @option{--epub3}), plain text (with @option{--plaintext}), @LaTeX{} (with @option{--latex}), DocBook (with @option{--docbook}), Texinfo XML (with @option{--xml}). @end display @command{makeinfo} is an alias for @command{texi2any}. By default, both @command{texi2any} and @command{makeinfo} generate Info output; indeed, there are no differences in behavior based on the name. Beside these default formats, command line options to @command{texi2any} can change many aspects of the output. Beyond that, initialization files provide even more control over the final output---nearly anything not specified in the Texinfo input file. Initialization files are written in Perl, like the main program, and anything which can be specified on the command line can also be specified within a initialization file. @node Invoking @command{texi2any} @nodedescription Running the translator from a shell. @section Invoking @command{texi2any} from a Shell @anchor{Invoking makeinfo} @pindex makeinfo @pindex texi2any To process a Texinfo file, invoke @command{texi2any} followed by the name of the Texinfo file. Also select the format you want to output with the appropriate command line option (default is Info). Thus, to create the Info file for Bison, type the following to the shell: @example texi2any --info bison.texi @end example You can specify more than one input file name; each is processed in turn. If an input file name is @samp{-}, standard input is read. @anchor{@command{makeinfo} Options} @c anchor{makeinfo options}@c prev name, but case-insensitive clash @cindex @command{makeinfo} options @cindex Options for @command{makeinfo} @anchor{@command{texi2any} Options} @cindex @command{texi2any} options @cindex Options for @command{texi2any} The @command{texi2any} program accepts many options. Perhaps the most basic are those that change the output format. By default, @command{texi2any} outputs Info. Each command line option is either a long name preceded by @samp{--} or a single letter preceded by @samp{-}. You can use abbreviations for the long option names as long as they are unique. For example, you could use the following shell command to create an Info file for @file{bison.texi} in which lines are filled to only 68 columns: @example texi2any --fill-column=68 bison.texi @end example You can write two or more options in sequence, like this: @example texi2any --no-split --fill-column=70 @dots{} @end example @noindent (This would keep the Info file together as one possibly very long file and would also set the fill column to 70.) The options are (approximately in alphabetical order): @table @code @item --commands-in-node-names @opindex --commands-in-node-names This option now does nothing, but remains for compatibility. (It used to ensure that @@-commands in node names were expanded throughout the document, especially @code{@@value}. This is now done by default.) @item --conf-dir=@var{dir} @opindex --conf-dir=@var{dir} Prepend @var{dir} to the directory search list for finding customization files that may be loaded with @option{--init-file} (see below). The @var{dir} value can be a single directory, or a list of several directories separated by the usual path separator character (@samp{:} on Unix-like systems, @samp{;} on Windows). @c @xref{Loading @c Init Files}. @item --css-include=@var{file} @opindex --css-include When producing HTML, literally include the contents of @var{file}, which should contain Cascading Style Sheets specifications, in the @samp{<style>} block of the HTML output. If @var{file} is @samp{-}, read standard input. @xref{HTML CSS}. @item --css-ref=@var{url} @opindex --css-ref When producing HTML, add a @samp{<link>} tag to the output which references a cascading style sheet at @var{url}. This allows using standalone style sheets. @item -D @var{var} @itemx -D '@var{var} @var{value}' @opindex -D @var{var} Cause the Texinfo variable @var{var} to be defined. This is equivalent to @code{@@set @var{var}} in the Texinfo file (@pxref{@code{@@set @@clear @@value}}). The argument to the option is always one word to the shell; if it contains internal whitespace, the first word is taken as the variable name and the remainder as the value. For example, @code{-D 'myvar someval'} is equivalent to @code{@@set myvar someval}. @item --docbook @opindex --docbook Generate DocBook output (rather than Info). @item --document-language=@var{lang} @opindex --document-language Use @var{lang} to translate Texinfo keywords which end up in the output document. The default is the locale specified by the @code{@@documentlanguage} command if there is one, otherwise English (@pxref{@code{@@documentlanguage}}). @item --dvi @opindex --dvi Generate a TeX DVI file using @command{texi2dvi}, rather than Info (@pxref{@command{texi2any} Printed Output}). @item --dvipdf @opindex --dvipdf Generate a PDF file using @command{texi2dvi --dvipdf}, rather than Info (@pxref{@command{texi2any} Printed Output}). @item --enable-encoding @itemx --disable-encoding @opindex --enable-encoding @opindex --disable-encoding @vindex ENABLE_ENCODING By default, or with @option{--enable-encoding}, output accented and special characters in Info and plain text output based on the document encoding. With @option{--disable-encoding}, 7-bit ASCII transliterations are output. Also obeyed in other output formats for index keys sorting and for some plain text output. @item --epub3 @opindex --epub3 Generate EPUB 3 output. @item --error-limit=@var{limit} @itemx -e @var{limit} @opindex --error-limit=@var{limit} @opindex -e @var{limit} @vindex ERROR_LIMIT Report @var{limit} errors before aborting (on the assumption that continuing would be useless); default 100. @item --fill-column=@var{width} @itemx -f @var{width} @opindex --fill-column=@var{width} @opindex -f @var{width} @vindex FILLCOLUMN Specify the maximum number of columns in a line; this is the right-hand edge of a line. Paragraphs that are filled will be filled to this width. (Filling is the process of breaking up and connecting lines so that lines are the same length as or shorter than the number specified as the fill column. Lines are broken between words.) The default value is 72. @item --footnote-style=@var{style} @itemx -s @var{style} @opindex --footnote-style=@var{style} @opindex -s @var{style} @vindex footnotestyle Set the footnote style to @var{style}: either @samp{end} for the end node style (the default) or @samp{separate} for the separate node style. The value set by this option overrides the value set in a Texinfo file by a @code{@@footnotestyle} command (@pxref{Footnote Styles}). In Info, when the footnote style is @samp{separate}, @command{texi2any} makes a new node containing the footnotes found in the current node. When the footnote style is @samp{end}, @command{texi2any} places the footnote references at the end of the current node. In HTML, when the footnote style is @samp{end}, or if the output is not split, footnotes are put at the end of the output. If set to @samp{separate}, and the output is split, they are placed in a separate file. @item --force @itemx -F @opindex --force @opindex -F @vindex FORCE Ordinarily, if the input file has errors, the output files are not created. With this option, they are preserved. @item --help @itemx -h @opindex --help@r{, for @command{texi2any}} @opindex -h Print a message with available options and basic usage, then exit successfully. @item --html @opindex --html Generate HTML output (rather than Info). By default, the HTML output is split into one output file per node, and the split output is written into a subdirectory based on the name of the input file. @xref{Generating HTML}. @item -I @var{dir} @opindex -I @var{dir} Append @var{dir} to the directory search list for finding files that are included using the @code{@@include} command. By default, @command{texi2any} searches only the current directory. If @var{dir} is not given, the current directory is appended. The @var{dir} value can be a single directory or a list of several directories separated by the usual path separator character (@samp{:} on Unix-like systems, @samp{;} on Windows). @item --ifdocbook @opindex --ifdocbook @itemx --ifhtml @opindex --ifhtml @itemx --ifinfo @opindex --ifinfo @itemx --iflatex @opindex --iflatex @itemx --ifplaintext @opindex --ifplaintext @itemx --iftex @opindex --iftex @itemx --ifxml @opindex --ifxml For the given format, process @samp{@@if@var{format}} and @samp{@@@var{format}} commands, and do not process @samp{@@ifnot@var{format}}, regardless of the format being output. For instance, if @option{--iftex} is given, then @samp{@@iftex} and @samp{@@tex} blocks will be read, and @samp{@@ifnottex} blocks will be ignored. @item --no-ifdocbook @opindex --no-ifdocbook @itemx --no-ifhtml @opindex --no-ifhtml @itemx --no-ifinfo @opindex --no-ifinfo @itemx --no-iflatex @opindex --no-iflatex @itemx --no-ifplaintext @opindex --no-ifplaintext @itemx --no-iftex @opindex --no-iftex @itemx --no-ifxml @opindex --no-ifxml For the given format, do not process @samp{@@if@var{format}} and @samp{@@@var{format}} commands, and do process @samp{@@ifnot@var{format}}, regardless of the format being output. For instance, if @option{--no-ifhtml} is given, then @samp{@@ifhtml} and @samp{@@html} blocks will not be read, and @samp{@@ifnothtml} blocks will be. @item --info @opindex --info Generate Info output. By default, if the output file contains more than about 300,000 bytes, it is split into shorter subfiles of about that size. The name of the output file and any subfiles is determined by the input file name, or by @code{@@setfilename}, if present (@pxref{Setting the Output File Name}). @xref{Tag and Split Files}. @item --init-file=@var{file} @opindex --init-file=@var{file} Load @var{file} as code to modify the behavior and output of the generated manual. It is customary to use the @code{.pm} or the @code{.init} extensions for these customization files, but that is not enforced; the @var{file} name can be anything. The @option{--conf-dir} option (see above) can be used to add to the list of directories in which these customization files are searched for. @c @xref{Loading Init Files}. @item --internal-links=@var{file} @opindex --internal-links=@var{file} @cindex Internal links, of HTML @vindex INTERNAL_LINKS In HTML mode, output a tab-separated file containing three columns: the internal link to an indexed item or item in the table of contents, the name of the index (or table of contents) in which it occurs, and the term which was indexed or entered. The items are in the natural sorting order for the given element. This dump can be useful for post-processors. @item --latex @opindex --latex Generate @LaTeX{} output. @item --macro-expand=@var{file} @itemx -E @var{file} @opindex --macro-expand=@var{file} @opindex -E @var{file} @vindex MACRO_EXPAND Output the Texinfo source, with all Texinfo macros expanded, to @var{file}. Normally, the result of macro expansion is used internally by @command{texi2any} and then discarded. @item --no-headers @opindex --no-headers @cindex Node separators, omitting with @option{--no-headers} @cindex Generating plain text files with @option{--no-headers} @cindex Menus, omitting with @option{--no-headers} @vindex HEADERS Do not include menus or node separator lines in the output. When generating Info, this is the same as using @option{--plaintext}, resulting in a simple plain text file. Furthermore, output is to standard output unless overridden with @option{-o}. (This behavior is for backward compatibility.) @cindex Navigation links, omitting When generating HTML, and output is split, also output navigation links only at the beginning of each file. If output is not split, do not include navigation links at the top of each node at all. @xref{Generating HTML}. @item --node-files @itemx --no-node-files @opindex --node-files @opindex --no-node-files @vindex NODE_FILES With @option{--node-files}, when generating HTML, create redirection files for anchors and any nodes not already output with the file name corresponding to the node name (@pxref{HTML Xref Node Name Expansion}). This makes it possible for section- and chapter-level cross-manual references to succeed (@pxref{HTML Xref Configuration}). If the output is split, this is enabled by default. If the output is not split, @option{--node-files} enables the creation of the redirection files, in addition to the monolithic main output file. @option{--no-node-files} suppresses the creation of redirection files in any case. This option has no effect with any output format other than HTML@. @xref{Generating HTML}. @item --no-validate @itemx --no-pointer-validate @opindex --no-validate @opindex --no-pointer-validate @cindex Pointer validation @anchor{Pointer Validation}@c Suppress the pointer-validation phase of @command{texi2any}---a dangerous thing to do. This can also be done with the @code{@@novalidate} command (@pxref{Formatting Partial Documents}). If you do not suppress pointer validation, @command{texi2any} will check the validity of cross-references and menu entries in the Texinfo file, as well as node pointers if they are given explicitly. @ignore @c TODO this may not be accurate If node pointers are implicitly determined, @command{texi2any} checks that the tree constructed from the document's menus matches the tree constructed from the sectioning commands. For example, if a chapter-level menu mentions nodes @var{n1} and @var{n2}, in that order, nodes @var{n1} and @var{n2} must be associated with @code{@@section} commands in the chapter. If node pointers are explicitly determined, here is the list of what is checked: @enumerate @item If a `Next', `Previous', or `Up' node reference is a reference to a node in the current file and is not an external reference such as to @file{(dir)}, then the referenced node must exist. @item Every node except the `Top' node must have an `Up' pointer. @item The node referenced by an `Up' pointer must itself reference the current node through a menu item, unless the node referenced by `Up' has the form @samp{(@var{file})}. @end enumerate @end ignore @item --no-warn @opindex --no-warn @vindex NO_WARN Suppress warning messages (but not error messages). @item --number-footnotes @itemx --no-number-footnotes @opindex --no-number-footnotes @vindex NUMBER_FOOTNOTES With @option{--no-number-footnotes}, suppress automatic footnote numbering. By default, footnotes are numbered sequentially within a node, i.e., the current footnote number is reset to 1 at the start of each node. @item --number-sections @itemx --no-number-sections @opindex --number-sections @opindex --no-number-sections @vindex NUMBER_SECTIONS With @option{--number-sections} (the default), output chapter, section, and appendix numbers as in printed manuals. This works only with hierarchically structured manuals. You should specify @code{--no-number-sections} if your manual is not normally structured. @item --output=@var{file} @itemx -o @var{file} @opindex --output=@var{file} @opindex -o @var{file} @vindex OUTFILE @vindex SUBDIR Specify that the output should be directed to @var{file}. This overrides any file name specified in a @code{@@setfilename} command found in the Texinfo source. If neither @code{@@setfilename} nor this option are specified, the input file name is used to determine the output name. @xref{Setting the Output File Name}. If @var{file} is @samp{-}, output goes to standard output and @samp{--no-split} is implied. If @var{file} is a directory or ends with a @samp{/} the usual rules are used to determine the output file name (namely, use @code{@@setfilename} or the input file name) but the files are written to the @var{file} directory. For example, @samp{texi2any -o bar/ foo.texi}, with or without @option{--no-split}, will write @file{bar/foo.info}, and possibly other files, under @file{bar/}. When generating HTML and output is split, @var{file} is used as the name for the directory into which all files are written. For example, @samp{texi2any -o bar --html foo.texi} will write @file{bar/index.html}, among other files. When generating EPUB a container directory for the files and directories needed for the EPUB format is created, as well as the EPUB output file. If @var{file} corresponds to a directory, the container directory is placed within @var{file}. The EPUB output file is never put in this directory. If @var{file} corresponds to a file, it is used for the EPUB output file name. @item --output-indent=@var{val} @opindex --outputindent This option now does nothing, but remains for compatibility. (It used to alter indentation in XML/DocBook output.) @item -P @var{path} @opindex -P @var{path} Prepend @var{path} to the directory search list for @code{@@include}. If @var{path} is not given, the current directory is prepended. See @samp{-I} above. @item --paragraph-indent=@var{indent} @itemx -p @var{indent} @opindex --paragraph-indent=@var{indent} @opindex -p @var{indent} Set the paragraph indentation style to @var{indent}. The value set by this option overrides the value set in a Texinfo file by an @code{@@paragraphindent} command (@pxref{@code{@@paragraphindent}}). The value of @var{indent} is interpreted as follows: @table @asis @item @samp{asis} Preserve any existing indentation (or lack thereof) at the beginnings of paragraphs. @item @samp{0} or @samp{none} Delete any existing indentation. @item @var{num} Indent each paragraph by @var{num} spaces. @end table The default is to indent by two spaces, except for paragraphs following a section heading, which are not indented. @item --pdf @opindex --pdf Generate a PDF file using @command{texi2dvi --pdf}, rather than Info (@pxref{@command{texi2any} Printed Output}). @item --plaintext @opindex --plaintext @cindex Plain text output with @option{--plaintext} @cindex ASCII text output with @option{--plaintext} @cindex Generating plain text files with @option{--plaintext} @cindex Node separators, omitting with @option{--plaintext} @cindex Menus, omitting with @option{--plaintext} @cindex @file{INSTALL} file, generating Output a plain text file (rather than Info): do not include menus or node separator lines in the output. This results in a straightforward plain text file that you can (for example) send in email without complications, or include in a distribution (for example, an @file{INSTALL} file). With this option the output goes to standard output by default, instead of to a file with a name based on the input file name or @code{@@setfilename}; this can be overridden with @option{-o}. @item --ps @opindex --ps Generate a PostScript file using @command{texi2dvi --ps}, rather than Info (@pxref{@command{texi2any} Printed Output}). @item --set-customization-variable @var{var}=@var{value} @itemx -c @var{var}=@var{value} @opindex --set-customization-variable @var{var}=@var{value} @opindex -c @var{var}=@var{value} Set the customization variable @var{var} to @var{value}. The @code{=} is optional, but both @var{var} and @var{value} must be quoted to the shell as necessary so the result is a single word. Many aspects of @command{texi2any} behavior and output may be controlled by customization variables, beyond what can be set in the document by @@-commands and with other command line switches. @xref{Customization Variables}. @item --split=@var{how} @itemx --no-split @opindex --split=@var{how} @opindex --no-split @cindex Splitting of output files @cindex Output file splitting @anchor{Splitting Output} @c When generating Info, by default large output files are split into smaller subfiles, of approximately 300k bytes. When generating HTML, by default each output file contains one node (@pxref{Generating HTML}). @option{--no-split} suppresses this splitting of the output. @vindex SPLIT Alternatively, @option{--split=@var{how}} may be used to specify at which level the HTML output should be split. The possible values for @var{how} are: @table @samp @item chapter The output is split at @code{@@chapter} and other sectioning @@-commands at this level (@code{@@appendix}, etc.). @item section The output is split at @code{@@section} and similar. @item node The output is split at every node. This is the default. @end table Plain text output can be split similarly to HTML@. This may be useful for extracting sections from a Texinfo document and making them available as separate files. @item --split-size=@var{num} @opindex --split-size=@var{num} @vindex SPLIT_SIZE Keep Info files to at most @var{num} characters if possible; default is 300,000. (However, a single node will never be split across Info files.) @item --transliterate-file-names @opindex --transliterate-file-names @vindex TRANSLITERATE_FILE_NAMES Enable transliteration of non-ASCII characters in node names for the purpose of file name creation. @xref{HTML Xref 8-bit Character Expansion}. @item -U @var{var} Cause @var{var} to be undefined. This is equivalent to @code{@@clear @var{var}} in the Texinfo file (@pxref{@code{@@set @@clear @@value}}). @item --verbose @opindex --verbose @vindex VERBOSE Cause @command{texi2any} to display messages saying what it is doing. Normally, @command{texi2any} only outputs messages if there are errors or warnings. @item --version @itemx -V @opindex --version@r{, for @command{texi2any}} @opindex -V Print the version number, then exit successfully. @item --Xopt @var{str} @opindex --Xopt @var{str} Pass @var{str} (a single shell word) to @command{texi2dvi}; may be repeated (@pxref{@command{texi2any} Printed Output}). @item --xml @opindex --xml Generate Texinfo XML output (rather than Info). @end table @node @command{texi2any} Environment Variables @nodedescription Control over output format and XS use. @section Environment Variables Recognized by @command{texi2any} @cindex Environment variable @code{TEXINFO_OUTPUT_FORMAT} @command{texi2any} also reads the environment variable @env{TEXINFO_OUTPUT_FORMAT} to determine the output format, if not overridden by a command line option. The value should be one of: @example docbook dvi dvipdf epub3 html info latex pdf plaintext ps xml @end example If not set or otherwise specified, Info output is the default. @code{TEXINFO_OUTPUT_FORMAT} may take some other special values, which do not correspond to any command-line settable output format (@pxref{Customization Variables and Options}). The customization variable of the same name is also read; if set, that overrides an environment variable setting, but not a command-line option. @xref{Customization Variables and Options}. @vindex TEXINFO_XS @cindex Perl extension modules (XS) You can control @command{texi2any}'s use of Perl extension modules by setting the @env{TEXINFO_XS} environment variable. These modules are compiled native code that the interpreted Perl code can use. Ideally, these extension modules should just work, and the only noticeable difference they should make is that @command{texi2any} finishes running sooner. However, you can use this environment variable for the purposes of troubleshooting: for example, if you have problems with the output of @command{texi2any} varying depending on whether the extension modules are in use. The following values of @env{TEXINFO_XS} are recognized by @command{texi2any}: @table @samp @item default The default behavior. Try to load extension modules, and silently fall back to the interpreted Perl implementations if this fails. @item warn Try to load extension modules, and if this fails, give a warning message before falling back to the interpreted Perl implementations. @item debug Try to load extension modules, printing many messages while doing so. @item omit Do not use extension modules. @end table @vindex TEXINFO_XS_PARSER Set @env{TEXINFO_XS_PARSER} to @samp{0} to disable the use of the native code implementation of the parser module. This is the part of @command{texi2any} that converts Texinfo input into an internal tree format used for further processing into output formats. This may be useful for working around bugs or incompatibilities between the native code implementation and the implementation in pure Perl code. @node @command{texi2any} Printed Output @nodedescription Calling @command{texi2dvi}. @section @command{texi2any} Printed Output @cindex Printed output, through @command{texi2any} @cindex Output, printed through @command{texi2any} To justify the name Texinfo-to-@emph{any}, @command{texi2any} has basic support for creating printed output in the various formats: @TeX{} DVI, PDF, and PostScript. This is done via the simple method of executing the @command{texi2dvi} program when those output formats are requested, after checking the validity of the input to give users the benefit of @command{texi2any}'s error checking. If you don't want such error checking, perhaps because your manual plays advanced @TeX{} tricks together with @file{texinfo.tex}, just invoke @command{texi2dvi} directly. The output format options for this are @option{--dvi}, @option{--dvipdf}, @option{--pdf}, and @option{--ps}. @xref{Format with @command{texi2dvi}}, for more details on these options and general @command{texi2dvi} operation. In addition, the @option{--verbose}, @option{--silent}, and @option{--quiet} options are passed on if specified; the @option{-I} and @option{-o} options are likewise passed on with their arguments, and @option{--debug} without its argument. The only option remaining that is related to the @command{texi2dvi} invocation is @option{--Xopt}. Here, just the argument is passed on and multiple @option{--Xopt} options accumulate. This provides a way to construct an arbitrary command line for @command{texi2dvi}. For example, running @example texi2any --Xopt -t --Xopt @@a4paper --pdf foo.texi @end example @noindent is equivalent to running @example texi2dvi -t @@a4paper --pdf foo.texi @end example @noindent except for the validity check. Although one might wish that other options to @command{texi2any} would take effect, they don't. For example, running @samp{texi2any --no-number-sections --dvi foo.texi} still results in a DVI file with numbered sections. (Perhaps this could be improved in the future, if requests are received.) The actual name of the command that is invoked is specified by the @code{TEXI2DVI} customization variable (@pxref{Other Customization Variables}). As you might guess, the default is @samp{texi2dvi}. @command{texi2any} itself does not generate any normal output when it invokes @command{texi2dvi}, only diagnostic messages. @node Customization Variables @nodedescription Configuring @command{texi2any}. @section Customization Variables @quotation Warning These customization variable names and meanings may change in any Texinfo release. We always try to avoid incompatible changes, but we cannot absolutely promise, since needs change over time. @end quotation Many aspects of the behavior and output of @command{texi2any} may be modified by modifying so-called @dfn{customization variables}. These fall into a few general categories: @itemize @bullet @item Those associated with @@-commands; for example, @code{@@documentlanguage}. @item Those associated with command-line options; for example, the customization variable @code{SPLIT} is associated with the @option{--split} command-line option, and @code{TEXINFO_OUTPUT_FORMAT} allows specifying the output format. @item Those associated with customizing the HTML output. @item Other ad hoc variables. @end itemize Customization variables may set on the command line using @code{--set-customization-variable '@var{var} @var{value}'} (quoting the variable/value pair to the shell) or @code{--set-customization-variable @var{var}=@var{value}} (using @code{=}). A special @var{value} is @samp{undef}, which sets the variable to this special ``undefined'' Perl value. The sections below give the details for each of these. @menu * Commands: Customization Variables for @@-Commands. * Options: Customization Variables and Options. * HTML: HTML Customization Variables. * MathJax: MathJax Customization Variables. * latex2html: @command{latex2html} Customization Variables. * tex4ht: @command{tex4ht} Customization Variables. * LaTeX: @LaTeX{} Customization Variables. * Other: Other Customization Variables. @end menu @node Customization Variables for @@-Commands @subsection Customization Variables for @@-Commands @cindex Customization variables for @@-commands @cindex @sortas{at} @@-commands @subentry customization variables for Each of the following @@-commands has an associated customization variable with the same name (minus the leading @code{@@}): @example @@afivepaper @@afourpaper @@afourlatex @@afourwide @@allowcodebreaks @@bsixpaper @@contents @@clickstyle @@codequotebacktick @@codequoteundirected @@deftypefnnewline @@documentdescription @@documentencoding @@documentlanguage @@evenfooting @@evenfootingmarks @@evenheading @@evenheadingmarks @@everyfooting @@everyfootingmarks @@everyheading @@everyheadingmarks @@exampleindent @@firstparagraphindent @@fonttextsize @@footnotestyle @@frenchspacing @@headings @@kbdinputstyle @@microtype @@novalidate @@oddfooting @@oddfootingmarks @@oddheading @@oddheadingmarks @@pagesizes @@paragraphindent @@setfilename @@setchapternewpage @@shortcontents @@smallbook @@summarycontents @@urefbreakstyle @@xrefautomaticsectiontitle @end example Setting such a customization variable to a value @samp{foo} is similar to executing @code{@@@var{cmd} foo}. It is not exactly the same, though, since any side effects of parsing the Texinfo source are not redone. Also, some variables do not take Texinfo code when generating particular formats, but an argument that is already formatted. This is the case, for example, for HTML for @code{documentdescription}. Note that if @command{texi2any} is invoked to process the file with @TeX{} (e.g., with the @option{--pdf} option), then these customization variables may not be passed on to @TeX{}. @node Customization Variables and Options @subsection Customization Variables and Options @cindex Customization variables for options @cindex Options, customization variables for The following table gives the customization variables associated with some command line options. @xref{Invoking @command{texi2any}}, for the meaning of the options. @multitable @columnfractions 0.5 0.5 @headitem Option @tab Variable @item @option{--enable-encoding} @tab @code{ENABLE_ENCODING} @item @option{--document-language} @tab @code{documentlanguage} @item @option{--error-limit} @tab @code{ERROR_LIMIT} @item @option{--fill-column} @tab @code{FILLCOLUMN} @item @option{--footnote-style} @tab @code{footnotestyle} @item @option{--force} @tab @code{FORCE} @item @option{--internal-links} @tab @code{INTERNAL_LINKS} @item @option{--macro-expand} @tab @code{MACRO_EXPAND} @item @option{--headers} @tab @code{HEADERS}, @code{FORMAT_MENU} @item @option{--no-warn} @tab @code{NO_WARN} @item @vindex novalidate @option{--no-validate} @tab @code{novalidate} @item @option{--number-footnotes} @tab @code{NUMBER_FOOTNOTES} @item @option{--number-sections} @tab @code{NUMBER_SECTIONS} @item @option{--node-files} @tab @code{NODE_FILES} @item @option{--output} @tab @code{OUTFILE}, @code{SUBDIR} @item @vindex paragraphindent @option{--paragraph-indent} @tab @code{paragraphindent} @item @option{--silent} @tab @code{SILENT} @item @option{--split} @tab @code{SPLIT} @item @option{--split-size} @tab @code{SPLIT_SIZE} @item @option{--transliterate-file-names} @tab @code{TRANSLITERATE_FILE_NAMES} @item @option{--verbose} @tab @code{VERBOSE} @end multitable Setting such a customization variable to a value @samp{foo} is essentially the same as specifying the @code{--@var{opt}=foo} if the option takes an argument, or @code{--@var{opt}} if not. @vindex TEXINFO_OUTPUT_FORMAT In addition, the customization variable @code{TEXINFO_OUTPUT_FORMAT} allows specifying what @command{texi2any} outputs, either one of the usual output formats that can be specified with options, or various other forms: @table @samp @item docbook @itemx dvi @itemx dvipdf @itemx epub3 @itemx html @itemx info @itemx pdf @itemx plaintext @itemx ps @itemx xml These correspond to the command-line options (and @code{TEXINFO_OUTPUT_FORMAT} environment variable values) of the same name. @xref{Invoking @command{texi2any}}. @cindex tree representation, for debugging @cindex debugging document, with tree representation @item debugtree Instead of generating a regular output format, output a text representation of the tree obtained by parsing the input texinfo document. @item parse Do only Texinfo source parsing; there is no output. @item plaintexinfo Output the Texinfo source with all the macros, @code{@@include} and @code{@@value@{@}} expanded. This is similar to setting @option{--macro-expand}, but instead of being output in addition to the normal conversion, output of Texinfo is the main output. @cindex raw text output @item rawtext Output raw text, with minimal formatting. For example, footnotes are ignored and there is no paragraph filling. This is used by the parser for file names and copyright text in HTML comments, for example. @item structure Do only Texinfo source parsing and determination of the document structure; there is no output. @cindex SXML output @cindex S-expressions, output format @item texinfosxml Output the document in TexinfoSXML representation, a syntax for writing XML data using Lisp S-expressions. @cindex spell checking @cindex word counting @pindex detexinfo @cindex stripping Texinfo commands @item textcontent Output the text content only, stripped of commands; this is useful for spell checking or word counting, for example. The trivial @code{detexinfo} script setting this is in the @file{util} directory of the Texinfo source as an example. It's one line: @example exec texi2any -c TEXINPUT_OUTPUT_FORMAT=textcontent "$@@" @end example @end table @node HTML Customization Variables @subsection HTML Customization Variables This table gives the customization variables which apply to HTML output only. A few other customization variables apply to both HTML and other output formats; see @ref{Other Customization Variables}. @vtable @code @item AVOID_MENU_REDUNDANCY If set, and the menu entry and menu description are the same, then do not print the menu description; default false. @item AFTER_BODY_OPEN If set, the corresponding text will appear at the beginning of each HTML file; default unset. @item AFTER_SHORT_TOC_LINES @itemx AFTER_TOC_LINES If set, the corresponding text is output after the short table of contents for @code{AFTER_SHORT_TOC_LINES} and after the table of contents for @code{AFTER_TOC_LINES}; otherwise, a default string is used. At the time of writing, a @code{</div>} element is closed. In general, you should set @code{BEFORE_SHORT_TOC_LINES} if @code{AFTER_SHORT_TOC_LINES} is set, and you should set @code{BEFORE_TOC_LINES} if @code{AFTER_TOC_LINES} is set. @item BASEFILENAME_LENGTH The maximum length of a base file name; default 245. Changing this would make cross-manual references to such long node names invalid (@pxref{HTML Xref Link Basics}). @item BEFORE_SHORT_TOC_LINES @itemx BEFORE_TOC_LINES If set, the corresponding text is output before the short table of contents for @code{BEFORE_SHORT_TOC_LINES} and before the table of contents for @code{BEFORE_TOC_LINES}, otherwise a default string is used. At the time of writing, a @code{<div ...>} element is opened. In general you should set @code{AFTER_SHORT_TOC_LINES} if @code{BEFORE_SHORT_TOC_LINES} is set, and you should set @code{AFTER_TOC_LINES} if @code{BEFORE_TOC_LINES} is set. @item BIG_RULE Rule used after and before the top element and before special elements, but not for footers and headers; default @code{<hr>}. @cindex @code{<body>} text, customizing @opindex lang@r{, HTML attribute} @item BODYTEXT The text appearing in @code{<body>}. By default, sets the HTML @code{lang} attribute to the document language (@pxref{@code{@@documentlanguage}}). @item CASE_INSENSITIVE_FILENAMES Construct output file names as if the filesystem were case insensitive (@pxref{HTML Splitting}); default false. @item CHAPTER_HEADER_LEVEL Header formatting level used for chapter level sectioning commands; default @samp{2}. @item CHECK_HTMLXREF Check that manuals which are the target of external cross-references (@pxref{Four and Five Arguments}) are present in @file{htmlxref.cnf} (@pxref{HTML Xref Configuration}); default false. @item COMPLEX_FORMAT_IN_TABLE If set, use tables for indentation of complex formats; default false. @item CONTENTS_OUTPUT_LOCATION If set to @samp{after_top}, output the contents at the end of the @code{@@top} section. If set to @samp{inline}, output the contents where the @code{@@contents} and similar @@-commands are located. If set to @samp{separate_element} output the contents in separate elements, either at the end of the document if not split, or in a separate file. If set to @samp{after_title} the tables of contents are output after the title; default @samp{after_top}. @item CONVERT_TO_LATEX_IN_MATH If set, try to convert any Texinfo @@-commands inside @code{@@math} and @code{@@displaymath} to @LaTeX{}, before converting the @code{@@math} or @code{@@displaymath} to HTML. Default @code{undef}. If undefined, set if @code{HTML_MATH} is set. @item COPIABLE_LINKS If set, output copiable links for the definition commands (@pxref{Definition Commands}) and table commands (@pxref{Two-column Tables}) where an index entry is defined. A link appears as a `@U{00B6}' @c pilcrow sign sign that appears when you hover the mouse pointer over the heading text. @item DATE_IN_HEADER Put the document generation date in the header; off by default. @item DEF_TABLE If set, a @code{<table>} construction for @code{@@deffn} and similar @@-commands is used (looking more like the @TeX{} output), instead of definition lists; default false. @item DEFAULT_RULE Rule used between element, except before and after the top element, and before special elements, and for footers and headers; default @code{<hr>}. @item DO_ABOUT If set to 0 never do an About special element; if set to 1 always do an About special element; default 0. @c @xref{Output Elements Defined}. @item EXTERNAL_CROSSREF_SPLIT For cross-references to other manuals, this determines if the other manual is considered to be split or monolithic. By default, it is set based on the value of @code{SPLIT}. @xref{HTML Xref}, and @pxref{HTML Xref Configuration}. @item EXTERNAL_DIR Base directory for external manuals; default none. It is better to use the general external cross-reference mechanism (@pxref{HTML Xref Configuration}) than this variable. @item EXTERNAL_CROSSREF_EXTENSION File extension for cross-references to other manuals. If unset, based on @code{EXTENSION}. @item EXTRA_HEAD Additional text appearing within @code{<head>}; default unset. @item FOOTNOTE_END_HEADER_LEVEL Header formatting level used for the footnotes header with the `end' footnotestyle; default @samp{4}. @xref{Footnote Styles}. @item FOOTNOTE_SEPARATE_HEADER_LEVEL Header formatting level used for the footnotes header with the `separate' footnotestyle; default @samp{4}. @xref{Footnote Styles}. @item FRAMES If set, a file describing the frame layout is generated, together with a file with the short table of contents; default false. @item FRAMESET_DOCTYPE Same as DOCTYPE, but for the file containing the frame description. @item HEADER_IN_TABLE Use tables for header formatting rather than a simple @code{<div>} element; default false. @item HTML_MATH Method to use to render @code{@@math}. This can be unset, set to @samp{mathjax} (@pxref{MathJax Customization Variables}), set to @samp{l2h}, which uses @command{latex2html} (@pxref{@command{latex2html} Customization Variables}), or set to @samp{t4h}, which uses @command{tex4ht} (@pxref{@command{tex4ht} Customization Variables}). In the default case, setting @code{HTML_MATH} also sets @code{CONVERT_TO_LATEX_IN_MATH}. @item HTML_ROOT_ELEMENT_ATTRIBUTES Use that string for the @code{<html>} HTML document root element. Default undefined. @item HTMLXREF_FILE Set the file name used for cross-references to other manuals. If not defined, @file{htmlxref.cnf} is used (@pxref{HTML Xref Configuration}). Not defined in the default case. If @code{TEST} is set, @code{HTMLXREF_MODE} is set to the default and @code{HTMLXREF_FILE} is not defined, information on cross-references to other manuals is not used. If @code{HTMLXREF_MODE} is set to @samp{file} the file name is directly used as the source of information, otherwise the file name is searched for in directories, and all the files found are used (@pxref{HTML Xref Configuration}). @item HTMLXREF_MODE How cross-references to other manuals information is determined. If set to @samp{none}, no information is used. If set to @samp{file}, the information is determined from a file path, @file{htmlxref.cnf} in the default case, or the value of @code{HTMLXREF_FILE}. If not defined (the default) or set to any other value, search in directories and use all the files (@pxref{HTML Xref Configuration}). @item ICONS Use icons for the navigation panel; default false. @item IMAGE_LINK_PREFIX If set, the associated value is prepended to the image file links; default unset. @item INDEX_ENTRY_COLON Symbol used between the index entry and the associated node or section; default @samp{:}. @item INFO_JS_DIR (Experimental.) Add a JavaScript browsing interface to the manual. The value of the variable is the directory to place the code for this interface, so you would run the program as e.g.@: @samp{texi2any --html -c INFO_JS_DIR=js @var{manual}.texi} to place files in a @samp{js} directory under the output. This provides some of the functionality of the Info browsers in a web browser, such as keyboard navigation and index lookup. This only works with non-split HTML output. The interface should provide an acceptable fallback in functionality if JavaScript or web browser features are not available. However, please be cautious when using this option, in case you do make your documentation harder to access for some of your users. @item IGNORE_REF_TO_TOP_NODE_UP Ignore references to @code{TOP_NODE_UP}, the up node for the Top node. @item INLINE_CSS_STYLE Put CSS directly in HTML elements rather than at the beginning of the output; default false. @item JS_WEBLABELS @itemx JS_WEBLABELS_FILE Specify how to use a @dfn{JavaScript license web labels} page to give licensing information and source code for any JavaScript used in the HTML files for the manual. (See @uref{https://www.gnu.org/licenses/javascript-labels.html}). With the value @samp{generate} (the default), generate a labels page at @code{JS_WEBLABELS_FILE}, and link to it in the HTML output files. Only do this if actually referencing JavaScript files (either with @code{HTML_MATH} set to @samp{mathjax}, or when using the experimental JS browsing interface when @code{INFO_JS_DIR} is set). With this setting, @code{JS_WEBLABELS_FILE} must be a relative file name. With the value @samp{reference}, link to the labels file given by @code{JS_WEBLABELS_FILE} in the output, and do not generate a labels file. This setting is useful if you separately maintain a single labels file for a larger website that includes your manual. With @samp{omit}, neither generate nor link to a labels file. @item MAX_HEADER_LEVEL Maximum header formatting level used (higher header formatting level numbers correspond to lower sectioning levels); default @samp{4}. @item MENU_ENTRY_COLON Symbol used between the menu entry and the description; default @samp{:}. @item MENU_SYMBOL Symbol used in front of menu entries when node names are used for menu entries formatting; default is undefined and set to @code{•} if @code{USE_NUMERIC_ENTITY} is not set, and to @code{’} if set. @item MONOLITHIC Output only one file including the table of contents. Set by default, but only relevant when the output is not split. @item NO_CSS Do not use CSS; default false. @xref{HTML CSS}. @item NO_CUSTOM_HTML_ATTRIBUTE Do not output HTML with custom attributes in elements; default false. @item NO_NUMBER_FOOTNOTE_SYMBOL Symbol used for footnotes if @code{NUMBER_FOOTNOTES} is false. Default is @code{*}. @item NODE_NAME_IN_INDEX If true, use node names in index entries, otherwise prefer section names. If undefined, use @code{USE_NODES} value in HTML. Default is undefined. @item PRE_BODY_CLOSE If set, the given text will appear at the footer of each HTML file; default unset. @item PROGRAM_NAME_IN_ABOUT Used when an About element is output. If set, output the program name and miscellaneous related information in About special element; default false. @item PROGRAM_NAME_IN_FOOTER If set, output the program name and miscellaneous related information in the page footers; default false. @item SECTION_NAME_IN_TITLE If set, when output is split, use the argument of the chapter structuring command (e.g., @code{@@chapter} or @code{@@section}) in the @code{<title>} instead of the argument to @code{@@node}. @item SHORT_TOC_LINK_TO_TOC If set, the cross-references in the Short table of contents links to the corresponding Table of Contents entries, if a Table of Contents is output; default true. @item SHOW_BUILTIN_CSS_RULES Output the built-in default CSS rules on the standard output and exit. @item SHOW_TITLE If set, output the title at the beginning of the document; default @samp{undef}. If set to @samp{undef}, setting @code{NO_TOP_NODE_OUTPUT} also sets @code{SHOW_TITLE} for HTML. @item SIMPLE_MENU If set, use a simple preformatted style for the menu, instead of breaking down the different parts of the menu; default false. @xref{Menu Parts}. @item TOC_LINKS If set, links from headings to toc entries are created; default false. @item TOP_FILE This file name may be used for the top-level file. The extension is set appropriately, if necessary. This is used to override the default, and is, in general, only taken into account when output is split, and for HTML@. @item TOP_NODE_FILE_TARGET File name used for the Top node in cross-references; default is @code{index.html}. @item TOP_NODE_UP_URL A URL used for Top node up references; the default is @code{undef}, in that case no Top node Up reference is generated. For more about the Top node pointers, @pxref{First Node}. For overriding the Up pointer name in case @code{TOP_NODE_UP_URL} is set and for other formats, see @code{TOP_NODE_UP} in @ref{Other Customization Variables}. @cindex @code{accesskey} @subentry customization variable for @item USE_ACCESSKEY Use @code{accesskey} in cross-references; default true. @item USE_ISO Use entities for doubled single-quote characters (@pxref{Inserting Quotation Marks}), and @samp{---} and @samp{--} (@pxref{Conventions}); default true. @cindex @code{<link>} HTML tag, in @code{<head>} @cindex @code{<head>} HTML tag, and @code{<link>} @item USE_LINKS Generate @code{<link>} elements in the HTML @code{<head>} output; default true. @item USE_NEXT_HEADING_FOR_LONE_NODE If set, a node not associated to a sectioning command but followed by a heading command not usually associated to node such as @code{@@heading} before other formatted contents do not have its name output as a heading, under the assumption that the command found provides the heading. Default true. @item USE_NODE_DIRECTIONS If true, use nodes to determine where next, up and prev link to in node headers. If false, use sections. If undefined, use @code{USE_NODES} value. Default is undefined. Note that this setting does not determine the link string only where the links points to, see @ref{Three Arguments, , xrefautomaticsectiontitle} for the link string customization. If nodes and sections are systematically associated, this customization has no practical effect. @item USE_REL_REV Use @code{rel} in cross-references; default true. @item USE_TITLEPAGE_FOR_TITLE Use the full @code{@@titlepage} as the title, not a simple title string; default true. Only relevant if @code{SHOW_TITLE} is set. @item USE_XML_SYNTAX Use XML/XHTML compatible syntax. @item VERTICAL_HEAD_NAVIGATION If set, a vertical navigation panel is used; default false. @cindex Navigation panel, bottom of page @cindex Navigation footer @item WORDS_IN_PAGE When output is split by nodes, specifies the approximate minimum page length at which a navigation panel is placed at the bottom of a page. To avoid ever having the navigation buttons at the bottom of a page, set this to a sufficiently large number. The default is 300. @item XREF_USE_FLOAT_LABEL If set, for the float name in cross-references, use the float label instead of the type followed by the float number (@pxref{@code{@@float}}). The default is off. @item XREF_USE_NODE_NAME_ARG Only relevant for cross-reference commands with no cross reference name (second argument). If set to@tie{}1, use the node name (first) argument in cross-reference @@-commands for the text displayed as the hyperlink. If set to@tie{}0, use the node name if @code{USE_NODES} is set, otherwise the section name. If set to @samp{undef}, use the first argument in preformatted environments, otherwise use the node name or section name depending on @code{USE_NODES}. The default is @samp{undef}. @end vtable @node MathJax Customization Variables @subsection MathJax Customization Variables This table lists the customization variables which can be used when MathJax is being used, which will be the case when @code{HTML_MATH} is set to @samp{mathjax}. @vtable @code @item MATHJAX_SCRIPT URL of the MathJax component file (e.g.@: @file{tex-svg.js}) you are using. @command{texi2any} provides a default value for this variable, but you are encouraged to host this file yourself on your website so that you are not dependent on others' hosting. @item MATHJAX_SOURCE A URL of the full source code in its preferred form for modification, or instructions for obtaining such source code, for the component file named by @code{MATHJAX_SCRIPT}. `Preferred form for modification' means that this should not be in a `minified' form. Used in the license labels page (@pxref{HTML Customization Variables}, under @code{JS_WEBLABELS}). Again, @command{texi2any} provides a default value for this variable, but you are encouraged to host the source code for MathJax and its dependencies yourself. This is in order to make the source code available reliably, and to reduce you and your users' dependence on others' distribution systems. @end vtable @node @command{latex2html} Customization Variables @subsection @command{latex2html} Customization Variables This table lists the customization variables which can be used when @command{latex2html} is being used to convert @code{@@math}, @code{@@displaymath}, @code{@@latex} and @code{@@tex} sections for HTML@. These customization variables are relevant only if @code{HTML_MATH} is set to @samp{l2h}. To actually convert @code{@@tex} sections, @option{--iftex} should be used, and to actually convert @code{@@latex} sections, @option{--iflatex} should be used. @vtable @code @item L2H_CLEAN If set, the intermediate files generated in relation with @command{latex2html} are removed; default true. @item L2H_FILE If set, the given file is used as @command{latex2html}'s init file; default unset. @item L2H_HTML_VERSION The HTML version used in the @command{latex2html} call; default unset. @item L2H_L2H The program invoked as @command{latex2html}; default is @code{latex2html}. @item L2H_SKIP If set to a true value, the actual call to @command{latex2html} is skipped; previously generated content is reused instead. If set to 0, the cache is not used at all. If set to @samp{undef}, the cache is used for as many @TeX{} fragments as possible and for any remaining the command is run. The default is @samp{undef}. @item L2H_TMP Set the directory used for temporary files. None of the file name components in this directory name may start with @samp{.}; otherwise, @command{latex2html} will fail (because of @command{dvips}). The default is the empty string, which means the current directory. @end vtable @node @command{tex4ht} Customization Variables @subsection @command{tex4ht} Customization Variables This table lists the customization variables which can be used when @command{tex4ht} is being used to convert @code{@@math}, @code{@@displaymath}, @code{@@tex} and @code{@@latex} sections for HTML@. These customization variables are relevant only if @code{HTML_MATH} is set to @samp{t4h}. To actually convert @code{@@tex} sections, @option{--iftex} should be used, and to actually convert @code{@@latex} sections, @option{--iflatex} should be used. @vtable @code @item T4H_LATEX_CONVERSION If set, the conversion type used for @code{@@latex} sections. Possibilities are @samp{latex}, @samp{tex} and @samp{texi}. Set to @samp{latex} if not defined. @item T4H_MATH_CONVERSION If set, the conversion type used for @code{@@math} and @code{@@displymath}. Possibilities are @samp{latex}, @samp{tex} and @samp{texi}. Set to @samp{tex} if not defined. @item T4H_TEX_CONVERSION If set, the conversion type used for @code{@@tex} sections. Possibilities are @samp{latex}, @samp{tex} and @samp{texi}. Set to @samp{tex} if not defined. @end vtable @node @LaTeX{} Customization Variables @subsection @LaTeX{} Customization Variables @cartouche @quotation warning @LaTeX{} output customization is experimental. Nothing is decided, everything can change, and we would welcome any feedback. @end quotation @end cartouche This table gives the customization variables which apply to @LaTeX{} output only. @vtable @code @item CLASS_BEGIN_USEPACKAGE If set, the corresponding text will replace the @LaTeX{} @code{\documentclass}, package imports that are always output and are output right after @code{\documentclass}, and package imports that depend on the document encoding setting the input and font encoding (@code{inputenc} and @code{fontenc}). The text replaced is along: @example LaTeX \documentclass@{book@} \usepackage@{amsfonts@} \usepackage@{amsmath@} \usepackage[gen]@{eurosym@} \usepackage@{textcomp@} \usepackage@{graphicx@} \usepackage@{etoolbox@} \usepackage@{titleps@} \usepackage[utf8]@{inputenc@} \usepackage[T1]@{fontenc@} @end example @item END_USEPACKAGE If set, the corresponding text will replace the package imports that depend on the Texinfo commands used, and the last packages imports that are always output and output after all the other packages imports. The last package imports corresponds to @samp{\usepackage[hidelinks]@{hyperref@}}. Here is an example of the corresponding text for a document with indices, @code{@@need}, @code{@@multitable}, definition commands, @code{@@cartouche}, lists, and @code{@@float}: @example LaTeX \usepackage@{imakeidx@} \usepackage@{needspace@} \usepackage@{array@} \usepackage@{embrac@} \usepackage@{expl3@} \usepackage@{tabularx@} \usepackage[framemethod=tikz]@{mdframed@} \usepackage@{enumitem@} \usepackage@{float@} \usepackage[hidelinks]@{hyperref@} @end example @end vtable @node Other Customization Variables @subsection Other Customization Variables This table gives the remaining customization variables, which apply to multiple formats, or affect global behavior, or otherwise don't fit into the categories of the previous sections. @vtable @code @item ASCII_DASHES_AND_QUOTES For Info output, when set, use plain ASCII characters to represent quotation marks, hyphens and dashes when these are given in the Texinfo source as @samp{-}, @samp{--}, @samp{---}, @samp{`}, @samp{``}, @samp{'}, and @samp{''}, rather than UTF-8 directional quotation marks, en dashes, vel sim. On by default. @item ASCII_GLYPH For Info output, use ASCII output for glyph commands such as the copyright sign (@command{@@copyright@{@}}, becoming @samp{(C)}), and the bullet symbol (@command{@@bullet@{@}}, becoming @samp{*}), rather than other Unicode sequences. Off by default. @item ASCII_PUNCTUATION Avoid any unncessary or gratuitious non-ASCII, UTF-8 sequences in the output. Implies both @code{ASCII_DASHES_AND_QUOTES} and @code{ASCII_GLYPH} and additionally affects the output of commands such as @code{@@samp} which output quotation marks. @item AUTO_MENU_DESCRIPTION_ALIGN_COLUMN For Info output, column at which to start a menu entry description provided by @code{@@nodedescription} or @code{@@nodedescriptionblock}. Undefined by default, in which case 45% of the fill column value is used (@pxref{Invoking @command{texi2any}}). @item AUTO_MENU_MAX_WIDTH Maximum number of columns in a menu entry line in Info when adding a description from @code{@@nodedescription} or @code{@@nodedescriptionblock}. Undefined by default, in which case 10% more than the fill column value is used (@pxref{Invoking @command{texi2any}}). @item CHECK_MISSING_MENU_ENTRY When a @code{@@menu} block occurs in a node, check if there is a menu entry for all subordinate nodes in the document sectioning structure. On by default. @item CHECK_NORMAL_MENU_STRUCTURE Warn if the node pointers (either explicitly or automatically set) are not consistent with the order of node menu entries. This is a more thorough structure check than that provided by @code{CHECK_MISSING_MENU_ENTRY}. Off by default. @item CLOSE_QUOTE_SYMBOL When a closing quote is needed, e.g. for @code{@@samp} output, use this character; default @code{’} in DocBook. Undefined in the default case in HTML and set to @code{’} if @code{USE_NUMERIC_ENTITY} is not set, to @code{’} if set, and to a quote character if @code{OUTPUT_CHARACTERS} is set and the output encoding includes that character. The default for Info is set the same as for @code{OPEN_QUOTE_SYMBOL}, except that the Unicode code is a closing quote (see below). @item CLOSE_DOUBLE_QUOTE_SYMBOL When a closing double quote is needed, for @samp{@@dfn} in Info, use this character. The default for Info is set the same as for @code{OPEN_DOUBLE_QUOTE_SYMBOL}, except that the Unicode code is a closing double quote (see below). @item COMMAND_LINE_ENCODING Encoding used to decode command-line arguments. Default is based on the locale encoding. This may affect file names inserted into output files or error messages printed by the program. Note that some file and directory names from the command line may not be decoded immediately, and may not be decoded at all. @item CPP_LINE_DIRECTIVES Recognize @code{#line} directives in a ``preprocessing'' pass (@pxref{External Macro Processors}); on by default. @item DEBUG If set, debugging output is generated; default is off (zero). @c The integer value specifies what kinds of debugging output are @c generated. It is a bitmask. Setting it to 255 ensures having all @c available debugging output. @item DOC_ENCODING_FOR_INPUT_FILE_NAME If set, use the input Texinfo document encoding information for the encoding of input file names, such as file names specified as @code{@@include} or @code{@@verbatiminclude} arguments. If unset, use the locale encoding instead. Default is set, except on MS-Windows where the locale encoding is used by default. Note that this is for file names only; the default encoding or @code{@@documentencoding} is always used for the encoding of file content (@pxref{@code{@@documentencoding}}). The @code{INPUT_FILE_NAME_ENCODING} variable overrides this variable. @item DOC_ENCODING_FOR_OUTPUT_FILE_NAME If set, use the input Texinfo document encoding information for the encoding of output file names, such as files specified with @option{--output}. If unset, use the locale encoding instead. Default is unset, so files names are encoded using the current locale. Note that this is for file names only; @code{OUTPUT_ENCODING_NAME} is used for the encoding of file content. The @code{OUTPUT_FILE_NAME_ENCODING} variable overrides this variable. @vindex SystemLiteral @item DOCTYPE For DocBook, HTML, XML@. Specifies the @code{SystemLiteral}, the entity's system identifier. This is a URI which may be used to retrieve the entity, and identifies the canonical DTD for the document. The default value is different for each of HTML, DocBook and XML. @item DUMP_TEXI For debugging. If set, no conversion is done, only parsing and macro expansion. If the option @option{--macro-expand} is set, the Texinfo source is also expanded to the corresponding file. Default false. @item DUMP_TREE For debugging. If set, the tree constructed upon parsing a Texinfo document is output to standard error; default false. @item EPUB_CREATE_CONTAINER_FILE If set to 0, do not generate the EPUB output file. Default is set to 1. @item EPUB_KEEP_CONTAINER_FOLDER If set, keep the directory containing the directories and files needed for EPUB. The EPUB output file is a ZIP archive of this directory. Default is not defined. Set if not defined and @code{TEST} or @code{DEBUG} is set. @xref{EPUB Output File and Directory}. @item EXTENSION The extension added to the output file name. The default is different for each output format. @item FORMAT_MENU If set to @samp{menu}, output Texinfo menus. This is the default for Info. @samp{sectiontoc} is the default setting for HTML, where instead of the contents of @code{@@menu} blocks being output, a list of subordinate sections is output in each node. If set to @samp{nomenu}, do not output menus. This variable is set to @samp{nomenu} when generating DocBook, or when @option{--no-headers} is specified. @c document? @ignore @item HANDLER_FATAL_ERROR_LEVEL This variable sets the error level above which errors returned by user defined functions registered to be called at different stages are considered to be fatal errors. You should not need to change this value. Default 100. @end ignore @item HIGHLIGHT_SYNTAX If set, @code{@@example} blocks with language information as first argument are highlighted in the HTML output. It is also possible to specify a default for the language with @code{HIGHLIGHT_SYNTAX_DEFAULT_LANGUAGE}. Syntax highlighting requires an external program to generate the highlighted HTML. The @code{HIGHLIGHT_SYNTAX} value allows to select a specific program. The possibilities are @code{highlight}, @code{pygments}, any other value standing for @code{source-highlight} (@pxref{Syntax Highlighting}). @item HIGHLIGHT_SYNTAX_DEFAULT_LANGUAGE The default language used for syntax highlighting when there is no language information. @item IGNORE_SPACE_AFTER_BRACED_COMMAND_NAME If set, spaces are ignored after an @@-command that takes braces. Default true, matching the @TeX{} behavior. @item INDEX_SPECIAL_CHARS_WARNING If set, warn about @samp{:} in index entry, as not all Info readers may be able to process these. For Info and plaintext only. Default false, because parsing problems there don't prevent navigation; readers can still relatively easily find their way to the node in question. @item INFO_SPECIAL_CHARS_QUOTE If set, whenever there are problematic characters for Info output in places such as node names or menu items, surround the part of the construct where they appear with quoting characters, as described in @ref{Info Format Specification}. Default is set for Info and unset for plaintext. @xref{Node Line Requirements}. @item INFO_SPECIAL_CHARS_WARNING If set, warn about problematic constructs for Info output (such as the string @samp{::}) in node names, menu items, and cross-references. If not defined, set unless @code{INFO_SPECIAL_CHARS_QUOTE} is set. Default is set for Info and not defined for plaintext. Similar warnings in index entries are covered by @code{INDEX_SPECIAL_CHARS_WARNING}. @cindex Encoding @subentry input file names @item INPUT_FILE_NAME_ENCODING Encoding used for input file names. This variable overrides any encoding from the document or current locale. Normally, you do not need to set this variable, but it can be used if file names are in a certain character encoding on a filesystem. An alternative is to set @code{DOC_ENCODING_FOR_INPUT_FILE_NAME} to @samp{0} to use the locale encoding. See also @code{OUTPUT_FILE_NAME_ENCODING}. @item LOCALE_ENCODING Locale encoding obtained from the system. You should not need to explicitly set this variable. @item MAX_MACRO_CALL_NESTING The maximal number of recursive calls of @@-commands defined through @code{@@rmacro}; default 100000. The purpose of this variable is to avoid infinite recursions. @item MESSAGE_ENCODING Encoding used to encode messages output by @command{texi2any}. Default is based on the locale encoding. It is also used for command-line argument passed to commands called from @command{texi2any}. For example, @command{latex2html} will be called from @command{texi2any} if @code{HTML_MATH} is set to @samp{l2h}. @item NO_TOP_NODE_OUTPUT @anchor{@code{NO_TOP_NODE_OUTPUT}} If set do not output the Top node content. The Top node is still parsed, but the content is discarded. Not set in the default case for HTML@. Set in the default case for EPUB@. If @code{SHOW_TITLE} is @samp{undef}, setting @code{NO_TOP_NODE_OUTPUT} also sets @code{SHOW_TITLE} for HTML. Setting @code{NO_TOP_NODE_OUTPUT}, which removes the Top node and adds a title page corresponds more to the formatting of a book. Setting @code{NO_TOP_NODE_OUTPUT} to false, with @code{SHOW_TITLE} remaining @samp{undef}, and false, corresponds more to a document setup for browsing, with a direct access to the information at the Top node. For DocBook, @code{NO_TOP_NODE_OUTPUT} is set to true. Setting @code{NO_TOP_NODE_OUTPUT} to false causes the Top node content to be output. It is not recommended to output the Top node in DocBook as the title and copying informations are always output. This option is kept for DocBook for compatibility, as before 2022 the Top node was output in DocBook. It could be removed in the future. @item NO_USE_SETFILENAME If set, do not use @code{@@setfilename} to set the document name; instead, base the output document name only on the input file name. The default is false. @item NODE_NAME_IN_MENU If set, use node names in menu entries, otherwise prefer section names; default true. @item OPEN_QUOTE_SYMBOL When an opening quote is needed, e.g., for @samp{@@samp} output, use the specified character; default @code{‘} for DocBook. Undefined in the default case in HTML and set to @code{‘} if @code{USE_NUMERIC_ENTITY} is not set, to @code{’} if set, and to a quote character if @code{OUTPUT_CHARACTERS} is set and the output encoding includes that character. For Info, the default depends on the enabled document encoding. If @option{--disable-encoding} is set or the document encoding is not UTF-8, @samp{'} is used. This character usually appears as an undirected single quote on modern systems. Otherwise, the Info output uses a Unicode left quote. @item OPEN_DOUBLE_QUOTE_SYMBOL When an opening double quote is needed, for @samp{@@dfn} output in Info, use the specified character. If @option{--disable-encoding} is set or the document encoding is not UTF-8, @samp{"} is used. Otherwise, the Info output uses a Unicode left double quote. @item OUTPUT_CHARACTERS If not set, the default, output accented and special characters in HTML, XML and DocBook using XML entities, and in @LaTeX{} using macros. If set, output accented characters in HTML, XML, DocBook and @LaTeX{} output and special characters in HTML and @LaTeX{} output based on the document encoding. @xref{@code{@@documentencoding}}, and @ref{Inserting Accents}. @item OUTPUT_ENCODING_NAME Normalized encoding name used for output files. Should be a usable charset name in HTML, typically one of the preferred IANA encoding names. By default, if an input encoding is set (typically through @code{@@documentencoding}), this information is used to set the output encoding name, otherwise the output encoding is based on the default encoding. @xref{@code{@@documentencoding}}. @cindex Encoding @subentry output file names @item OUTPUT_FILE_NAME_ENCODING Encoding used for output file names. This variable overrides any encoding from the document or current locale. Normally, you do not need to set this variable, but it can be used if file names should be created in a certain character encoding on a filesystem. See also @code{INPUT_FILE_NAME_ENCODING}. @item PACKAGE @itemx PACKAGE_VERSION @itemx PACKAGE_AND_VERSION @itemx PACKAGE_URL @itemx PACKAGE_NAME The implementation's short package name, package version, package name and version concatenated, package URL@:, and full package name, respectively. By default, these variables are all set through Autoconf, Automake, and @code{configure}. @item PREFIX The output file prefix, which is prepended to some output file names. By default it is set by @code{@@setfilename} or from the input file (@pxref{Setting the Output File Name}). How this value is used depends on the value of other customization variables or command line options, such as whether the output is split. The default is unset. @item PROGRAM Name of the program used. By default, it is set to the name of the program launched, with a trailing @samp{.pl} removed. @pindex texi-elements-by-size @cindex Longest nodes, finding @cindex Sorting nodes by size @item SORT_ELEMENT_COUNT If set, the name of a file to which a list of elements (nodes or sections, depending on the output format) is dumped, sorted by the number of lines they contain after removal of @@-commands; default unset. This is used by the program @code{texi-elements-by-size} in the @file{util/} directory of the Texinfo source distribution (@pxref{texi-elements-by-size}). @item SORT_ELEMENT_COUNT_WORDS When dumping the elements-by-size file (see preceding item), use word counts instead of line counts; default false. @item TEST If set to true, some variables which are normally dynamically generated anew for each run (date, program name, version) are set to fixed and given values. This is useful to compare the output to a reference file, as is done for the tests. The default is false. @item TEXI2DVI Name of the command used to produce PostScript, PDF, and DVI; default @samp{texi2dvi}. @xref{@command{texi2any} Printed Output}. @cindex compatibility, with @command{texi2html} @item TEXI2HTML Generate HTML and try to be as compatible as possible with @command{texi2html}; default false. @item TEXINFO_DTD_VERSION For XML@. Version of the DTD used in the XML output preamble. The default is set based on a variable in @file{configure.ac}. @item TEXTCONTENT_COMMENT For stripped text content output (i.e., when @code{TEXINFO_OUTPUT_FORMAT} is set to @code{textcontent}). If set, also output comments. Default false. @item TOP_NODE_UP Up node for the Top node; default @samp{(dir)}. This node name is supposed to be already formatted for the output format. In HTML can be used in attribute, so should not contain any element. Used for HTML output only if @code{TOP_NODE_UP_URL} is set to override the URL@:, see @code{TOP_NODE_UP_URL} in @ref{HTML Customization Variables}. @item TREE_TRANSFORMATIONS The associated value is a comma separated list of transformations that can be applied to the Texinfo tree prior to outputting the result. If more than one is specified, the ordering is irrelevant; each is always applied at the necessary point during processing. By default, the tree transformations @samp{move_index_entries_after_items} and @samp{relate_index_entries_to_table_entries} are executed for HTML and DocBook output. Here's an example of updating the master menu in a document: @example texi2any \ -c TREE_TRANSFORMATIONS=regenerate_master_menu \ -c TEXINFO_OUTPUT_FORMAT=plaintexinfo \ mydoc.texi \ -o /tmp/out @end example @noindent (Caveat: Since @samp{plaintexinfo} output expands Texinfo macros and conditionals, it's necessary to remove any such differences before installing the updates in the original document. This may be remedied in a future release.) The following transformations are currently supported (many are used in the @code{pod2texi} utility distributed with Texinfo; @pxref{Invoking @command{pod2texi}}): @ftable @samp @item complete_tree_nodes_menus Add menu entries or whole menus for nodes associated with sections of any level, based on the sectioning tree. @item complete_tree_nodes_missing_menu Add whole menus for nodes associated with sections without menu. The menus are based on the sectioning tree. @item fill_gaps_in_sectioning Adds empty @code{@@unnumbered...} sections in a tree to fill gaps in sectioning. For example, an @code{@@unnumberedsec} will be inserted if a @code{@@chapter} is followed by a @code{@@subsection}. @item insert_nodes_for_sectioning_commands Insert nodes for sectioning commands lacking a corresponding node. @item move_index_entries_after_items In @code{@@enumerate} and @code{@@itemize}, move index entries appearing just before an @code{@@item} to just after the @code{@@item}. Comment lines between index entries are moved too. As mentioned, this is always done for HTML and DocBook output. @item regenerate_master_menu Update the Top node master menu, either replacing the (first) @code{@@detailmenu} in the Top node menu, or creating it at the end of the Top node menu. @item relate_index_entries_to_table_entries In @code{@@table}, @code{@@vtable} and @code{@@ftable}, reassociate the index entry information from an index @@-command appearing right after an @code{@@item} line with the first element of the @code{@@item}. Remove the index @@-command from the tree. @item simple_menu Mostly the same as @code{SIMPLE_MENU}: use a simple preformatted style for the menu. It differs from setting @code{SIMPLE_MENU} in that @code{SIMPLE_MENU} only has an effect in HTML output. @end ftable @item USE_NODES Preferentially use nodes to decide where elements are separated. If set to false, preferentially use sectioning to decide where elements are separated. The default is true. @item USE_NUMERIC_ENTITY For HTML, XML and DocBook@. If set, use numeric entities instead of named entities. By default, set to true for DocBook output. @item USE_UP_NODE_FOR_ELEMENT_UP Fill in up sectioning direction with node direction when there is no sectioning up direction. In practice this can only happen when there is no @@top section. Not set by default. @item USE_SETFILENAME_EXTENSION Default is on for Info, off for other output. If set, use exactly what @code{@@setfilename} gives for the output file name, including the extension. You should not need to explicitly set this variable. @pindex Text::Unidecode @item USE_UNIDECODE If set to false, do not use the @code{Text::Unidecode} Perl module to transliterate more characters; default true. @end vtable @node Internationalization of Document Strings @nodedescription Translating program-inserted text. @section Internationalization of Document Strings @cindex I18n, of document strings @cindex Internationalization of document strings @cindex Document strings, internationalization of @cindex Output document strings, internationalization of @cindex Translating strings in output documents @vindex documentlanguage @r{customization variable} @command{texi2any} writes fixed strings into the output document at various places: cross-references, page footers, the help page, alternate text for images, and so on. The string chosen depends on the value of the @code{documentlanguage} at the time of the string being output (@pxref{@code{@@documentlanguage}}, for the Texinfo command interface). @pindex libintl-perl @r{Gettext implementation} The Gettext framework is used for those strings (@pxref{Top,,, gettext, Gettext}). The @code{libintl-perl} package is used as the @code{gettext} implementation; more specifically, the pure Perl implementation is used, so Texinfo can support consistent behavior across all platforms and installations, which would not otherwise be possible. @code{libintl-perl} is included in the Texinfo distribution and always installed, to ensure that it is available if needed. It is also possible to use the system @code{gettext} (the choice can be made at build-time). @vindex texinfo_document @r{Gettext domain} @cindex Perl format strings for translation The Gettext domain @samp{texinfo_document} is used for the strings. Translated strings are written as Texinfo, and may include @@-commands. In translated strings, the varying parts of the string are not usually denoted by @code{%s} and the like, but by @samp{@{arg_name@}}. (This convention is common for @code{gettext} in Perl and is fully supported in GNU Gettext; @pxref{perl-format,, Perl Format Strings, gettext, GNU Gettext}.) For example, in the following, @samp{@{section@}} will be replaced by the section name: @example see @{section@} @end example These Perl-style brace format strings are used for two reasons: first, changing the order of @code{printf} arguments is only available since Perl@tie{}5.8.0; second, and more importantly, the order of arguments is unpredictable, since @@-command expansion may lead to different orders depending on the output format. The expansion of a translation string is done like this: @enumerate @item First, the string is translated. The locale is @var{documentlanguage}@code{.}@var{documentencoding}. @cindex @code{us-ascii} encoding, and translations If the @var{documentlanguage} has the form @samp{ll_CC}, that is tried first, and then just @samp{ll}. To cope with the possibility of having multiple encodings, a special use of the @code{us-ascii} locale encoding is also possible. If the @samp{ll} locale in the current encoding does not exist, and the encoding is not @code{us-ascii}, then @code{us-ascii} is tried. The idea is that if there is a @code{us-ascii} encoding, it means that all the characters in the charset may be expressed as @@-commands. For example, there is a @code{fr.us-ascii} locale that can accommodate any encoding, since all the Latin@tie{}1 characters have associated @@-commands. On the other hand, Japanese has only a translation @code{ja.utf-8}, since there are no @@-commands for Japanese characters. The @code{us-ascii} locales are not needed much now that UTF-8 is used for most documents. Note that accented characters are required to be expressed as @@-commands in the @code{us-ascii} locales, which may be inconvenient for translators. @item Next, the string is expanded as Texinfo, and converted. The arguments are substituted; for example, @samp{@{arg_name@}} is replaced by the corresponding actual argument. @end enumerate In the following example, @samp{@{date@}}, @samp{@{program_homepage@}} and @samp{@{program@}} are the arguments of the string. Since they are used in @code{@@uref}, their order is not predictable. @samp{@{date@}}, @samp{@{program_homepage@}} and @samp{@{program@}} are substituted after the expansion: @example Generated on @@emph@{@{date@}@} using @@uref@{@{program_homepage@}, @@emph@{@{program@}@}@}. @end example This approach is admittedly a bit complicated. Its usefulness is that it supports having translations available in different encodings for encodings which can be covered by @@-commands, and also specifying how the formatting for some commands is done, independently of the output format---yet still be language-dependent. For example, the @samp{@@pxref} translation string can be like this: @example see @{node_file_href@} section `@{section@}' in @@cite@{@{book@}@} @end example @noindent which allows for specifying a string independently of the output format, while nevertheless with rich formatting it may be translated appropriately in many languages. @node Invoking @command{pod2texi} @nodedescription Translating Perl Pod to Texinfo. @section Invoking @command{pod2texi}: Convert Pod to Texinfo @pindex pod2texi @cindex Invoking @command{pod2texi} @cindex Pod, converting to Texinfo @cindex Perl Pod, converting to Texinfo The @command{pod2texi} program translates Perl Pod documentation file(s) to Texinfo. There are two basic modes of operation: generating a standalone manual from each input Pod, or (if @code{--base-level=1} or higher is given) generating Texinfo subfiles suitable for use with @code{@@include}. @c Although ordinarily this documentation in the Texinfo manual would be @c the best place to look, in this case we have documented all the @c options and examples in the @command{pod2texi} program itself, since it @c may be useful outside of the rest of Texinfo. Thus, please see the @c output of @code{pod2texi --help}, the version on the web at @c @url{http://www.gnu.org/software/texinfo/manual/pod2texi.html}, etc. The @command{pod2texi} program may be useful outside of the rest of Texinfo; thus, the invocation of @command{pod2texi} is documented in the Pod language using the man page format to follow the convention used in Perl standalone programs, with a version on the web @url{http://www.gnu.org/software/texinfo/manual/pod2texi.html} and a version included below. The version included in the manual is also an example of @command{pod2texi} use, as it is converted from Pod using @command{pod2texi}. @c there are issue with the perldoc-all generated files, as the perl documentation @c does not follows the Pod specification, there are anchors added @c using the first word in addition to the regular anchors. @c For an example of using @command{pod2texi} to make Texinfo out of the @c Perl documentation itself, see @file{contrib/perldoc-all}} in the Texinfo @c source distribution. @node pod2texi manual page @nodedescription @command{pod2texi} invocation in a manual page format. @include pod2texi.texi @node @command{texi2html} @nodedescription An ancestor of @command{texi2any}. @section @command{texi2html}: Ancestor of @command{texi2any} @pindex texi2html @cindex Cons, Lionel Conceptually, the @command{texi2html} program is the parent of today's @command{texi2any} program. @command{texi2html} was developed independently, originally by Lionel Cons in 1998; at the time, @command{makeinfo} could not generate HTML@. Many other people contributed to @command{texi2html} over the years. The present @command{texi2any} uses little of the actual code of @command{texi2html}, and has quite a different basic approach to the implementation (namely, parsing the Texinfo document into a tree), but still, there is a family resemblance. By design, @command{texi2any} supports nearly all the features of @command{texi2html} in some way. However, we did not attempt to maintain strict compatibility, so no @command{texi2html} executable is installed by the Texinfo package. An approximation can be run with an invocation like this: @example texi2any --set-customization-variable TEXI2HTML=1 ... @end example @noindent but, to emphasize, this is @emph{not} a drop-in replacement for the previous @command{texi2html}. Here are the biggest differences: @itemize @bullet @item Most blatantly, the command line options of @command{texi2html} are now customization variables, for the most part. A table of approximate equivalents is given below. @item The program-level customization API is very different in @command{texi2any}. @item Indices cannot be split. @end itemize We do not intend to reimplement these differences. Therefore, the route forward for authors is alter manuals and build processes as necessary to use the new features and methods of @command{texi2any}. The @command{texi2html} maintainers (one of whom is the principal author of @command{texi2any}) do not intend to make further releases. @cindex Options of @command{texi2html} @cindex Command-line options of @command{texi2html} Here is the table showing @command{texi2html} options and corresponding @command{texi2any} customization variables. @c (@pxref{texi2any Output Customization,, @command{texi2any} Output @c Customization}). @multitable {@option{--frameset-doctype}} {@code{HTML_MATH} set to @samp{l2h}} @item @option{--toc-links} @tab @code{TOC_LINKS} @item @option{--short-ext} @tab @code{EXTENSION} set to @samp{htm} @item @option{--prefix} @tab @code{PREFIX} @item @option{--def-table} @tab @code{DEF_TABLE} @item @option{--html-xref-prefix} @tab @code{EXTERNAL_DIR} @item @option{--l2h} @tab @code{HTML_MATH} set to @samp{l2h} @item @option{--l2h-l2h} @tab @code{L2H_L2H} @item @option{--l2h-skip} @tab @code{L2H_SKIP} @item @option{--l2h-tmp} @tab @code{L2H_TMP} @item @option{--l2h-file} @tab @code{L2H_FILE} @item @option{--l2h-clean} @tab @code{L2H_CLEAN} @item @option{--use-nodes} @tab @code{USE_NODES} @item @option{--monolithic} @tab @code{MONOLITHIC} @item @option{--top-file} @tab @code{TOP_FILE} @item @option{--frames} @tab @code{FRAMES} @item @option{--menu} @tab @code{FORMAT_MENU} @item @option{--debug} @tab @code{DEBUG} @item @option{--doctype} @tab @code{DOCTYPE} @item @option{--frameset-doctype} @tab @code{FRAMESET_DOCTYPE} @item @option{--test} @tab @code{TEST} @end multitable @cindex @file{texi2oldapi.texi}, for @command{texi2html} Finally, any @command{texi2html} users seeking more detailed information can check the first part of the archived file @file{doc/texi2oldapi.texi} in the Texinfo source repository. @node Creating and Installing Info Files @nodedescription Details on Info output. @chapter Creating and Installing Info Files @anchor{Creating an Info File}@c removed, merged to this node and Emacs Info mode This chapter gives some information on the Info output and describes how to install Info files. For the creation of Info files with @command{texi2any}, see @ref{Generic Translator @command{texi2any}}, and with Emacs, @ref{Info Formatting}. @xref{Info Files}, for general information about the file format. @xref{Info Format Specification}, for a detailed technical specification of the Info format. @node Installing an Info File @section Installing an Info File @cindex Installing an Info file @cindex Info files @subentry installation @cindex @file{dir} directory for Info installation Info files are usually kept in the @file{info} directory. You can read Info files using the standalone Info program or the Info reader built into Emacs. (@xref{Top,,, info, Info}, for an introduction to Info.) @node Directory File @nodedescription The top-level menu for all Info files. @subsection The Directory File @file{dir} For Info to work, the @file{info} directory must contain a file that serves as a top-level directory for the Info system. By convention, this file is called @file{dir}. (You can find the location of this file within Emacs by typing @kbd{C-h i} to enter Info and then typing @kbd{C-x C-f} to see the location of the @file{info} directory.) The @file{dir} file is itself an Info file. It contains the top-level menu for all the Info files in the system. The menu looks like this: @example @group * Menu: * Info: (info). Documentation browsing system. * Emacs: (emacs). The extensible, self-documenting text editor. * Texinfo: (texinfo). With one source file, make either a printed manual using @@TeX@{@} or an Info file. @dots{} @end group @end example Each of these menu entries points to the `Top' node of the Info file that is named in parentheses. (The menu entry does not need to specify the `Top' node, since Info goes to the `Top' node if no node name is mentioned. @xref{Other Info Files, , Nodes in Other Info Files}.) Thus, the @samp{Info} entry points to the `Top' node of the @file{info} file and the @samp{Emacs} entry points to the `Top' node of the @file{emacs} file. In each of the Info files, the `Up' pointer of the `Top' node refers back to the @code{dir} file. For example, the line for the `Top' node of the Emacs manual looks like this in Info: @example File: emacs Node: Top, Up: (DIR), Next: Distrib @end example @noindent In this case, the @file{dir} file name is written in uppercase letters---it can be written in either upper- or lowercase. This is not true in general, it is a special case for @file{dir}. See the @file{util/dir-example} file in the Texinfo distribution for a large sample @code{dir} file. @node New Info File @nodedescription Listing a new Info file. @subsection Listing a New Info File @cindex Adding a new Info file @cindex Listing a new Info file @cindex New Info file, listing it in @file{dir} file @cindex Info files @subentry listing a new @cindex @file{dir} file listing To add a new Info file to your system, you must write a menu entry to add to the menu in the @file{dir} file in the @file{info} directory. For example, if you were adding documentation for GDB, you would write the following new entry: @example * GDB: (gdb). The source-level C debugger. @end example @noindent The first part of the menu entry is the menu entry name, followed by a colon. The second part is the name of the Info file, in parentheses, followed by a period. The third part is the description. The name of an Info file often has a @file{.info} extension. Thus, the Info file for GDB might be called either @file{gdb} or @file{gdb.info}. The Info reader programs automatically try the file name both with and without @file{.info}@footnote{On MS-DOS/MS-Windows systems, Info will try the @file{.inf} extension as well.}; so it is better to avoid clutter and not to write @samp{.info} explicitly in the menu entry. For example, the GDB menu entry should use just @samp{gdb} for the file name, not @samp{gdb.info}. @node Other Info Directories @nodedescription How to specify Info files that are located in other directories. @subsection Info Files in Other Directories @cindex Installing Info in another directory @cindex Info installed in another directory @cindex Another Info directory @cindex @file{dir} files and Info directories If an Info file is not in the @file{info} directory, there are three ways to specify its location: @enumerate @item Write the file name in the @file{dir} file as the second part of the menu. @item Specify the Info directory name in the @code{INFOPATH} environment variable in your @file{.profile} or @file{.cshrc} initialization file. (Only you and others who set this environment variable will be able to find Info files whose location is specified this way.) @item If you are using Emacs, list the name of the file in a second @file{dir} file, in its directory; and then add the name of that directory to the @code{Info-directory-list} variable in your personal or site initialization file. This variable tells Emacs where to look for @file{dir} files (the files must be named @file{dir}). Emacs merges the files named @file{dir} from each of the listed directories. (In Emacs version 18, you can set the @code{Info-directory} variable to the name of only one directory.) @end enumerate For example, to reach a test file in the @file{/home/bob/info} directory, you could add an entry like this to the menu in the standard @file{dir} file: @example * Test: (/home/bob/info/info-test). Bob's own test file. @end example @noindent In this case, the absolute file name of the @file{info-test} file is written as the second part of the menu entry. @vindex INFOPATH @cindex Environment variable @code{INFOPATH} If you don't want to edit the system @file{dir} file, you can tell Info where to look by setting the @code{INFOPATH} environment variable in your shell startup file. This works with both the Emacs and standalone Info readers. Emacs uses the @code{INFOPATH} environment variable to initialize the value of Emacs's own @code{Info-directory-list} variable. The standalone Info reader merges any files named @file{dir} in any directory listed in the @env{INFOPATH} variable into a single menu presented to you in the node called @samp{(dir)Top}. @cindex Colon, last in @env{INFOPATH} However you set @env{INFOPATH}, if its last character is a colon (on MS-DOS/MS-Windows systems, use a semicolon instead), this is replaced by the default (compiled-in) path. This gives you a way to augment the default path with new directories without having to list all the standard places. For example (using @code{sh} syntax): @example INFOPATH=/home/bob/info: export INFOPATH @end example @noindent will search @file{/home/bob/info} first, then the standard directories. Leading or doubled colons are not treated specially. @cindex @file{dir} file, creating your own When you create your own @file{dir} file for use with @code{Info-directory-list} or @env{INFOPATH}, it's easiest to start by copying an existing @file{dir} file and replace all the text after the @samp{* Menu:} with your desired entries. That way, the punctuation and special @kbd{CTRL-_} characters that Info needs will be present. As one final alternative, which works only with Emacs Info, you can change the @code{Info-directory-list} variable. For example: @example (add-hook 'Info-mode-hook '(lambda () (add-to-list 'Info-directory-list (expand-file-name "~/info")))) @end example @node Installing Dir Entries @nodedescription How to specify what menu entry to add to the Info directory. @subsection Installing Info Directory Files When you install an Info file onto your system, you can use the program @code{install-info} to update the Info directory file @file{dir}. Normally the makefile for the package runs @code{install-info}, just after copying the Info file into its proper installed location. @findex direntry In order for the Info file to work with @code{install-info}, you include the commands @code{@@dircategory} and @code{@@direntry}@dots{}@code{@@end direntry} in the Texinfo source file. Use @code{@@direntry} to specify the menu entries to add to the Info directory file. Use @code{@@dircategory} to specify a category for the manual, which determines which part of the Info directory to put it in. @xref{Directory Category}. Here is how these commands are used in this manual: @example @@dircategory Texinfo documentation system @@direntry * Texinfo: (texinfo). The GNU documentation format. * install-info: (texinfo)Invoking install-info. @dots{} @dots{} @@end direntry @end example Here's what this produces in the Info file: @example INFO-DIR-SECTION Texinfo documentation system START-INFO-DIR-ENTRY * Texinfo: (texinfo). The GNU documentation format. * install-info: (texinfo)Invoking install-info. @dots{} @dots{} END-INFO-DIR-ENTRY @end example @noindent The @code{install-info} program sees these lines in the Info file, and that is how it knows what to do. Always use the @code{@@direntry} and @code{@@dircategory} commands near the beginning of the Texinfo input, before the first @code{@@node} command. If you use them later on in the input, @code{install-info} will not notice them. @code{install-info} will automatically reformat the description of the menu entries it is adding. As a matter of convention, the description of the main entry (above, @samp{The GNU documentation format}) should start at column 32, starting at zero (as in @code{what-cursor-position} in Emacs). This will make it align with most others. Description for individual utilities best start in column 48, where possible. For more information about formatting see the @samp{--calign}, @samp{--align}, and @samp{--max-width} options in @ref{Invoking @command{install-info}}. If you use @code{@@dircategory} more than once in the Texinfo source, each usage specifies the `current' category; any subsequent @code{@@direntry} commands will add to that category. @cindex Invoking nodes, including in dir file Each `Invoking' node for every program installed should have a corresponding @code{@@direntry}. This lets users easily find the documentation for the different programs they can run, as with the traditional @command{man} system. @node Invoking @command{install-info} @nodedescription @code{install-info} options. @subsection Invoking @command{install-info} @pindex install-info @code{install-info} inserts menu entries from an Info file into the top-level @file{dir} file in the Info system (see the previous sections for an explanation of how the @file{dir} file works). @code{install-info} also removes menu entries from the @file{dir} file. It's most often run as part of software installation, or when constructing a @file{dir} file for all manuals on a system. Synopsis: @example install-info [@var{option}@dots{}] [@var{info-file} [@var{dir-file}]] @end example If @var{info-file} or @var{dir-file} are not specified, the options (described below) that define them must be. There are no compile-time defaults, and standard input is never used. @code{install-info} can read only one Info file and write only one @file{dir} file per invocation. @cindex @file{dir}, created by @code{install-info} If @var{dir-file} (however specified) does not exist, @code{install-info} creates it if possible (with no entries). @cindex Compressed dir files, reading @cindex XZ-compressed dir files, reading @cindex Bzipped dir files, reading @cindex Lzip-compressed dir files, reading @cindex LZMA-compressed dir files, reading @cindex Dir files, compressed If any input file is compressed with @code{gzip} (@pxref{Top,,, gzip, Gzip}), @code{install-info} automatically uncompresses it for reading. And if @var{dir-file} is compressed, @code{install-info} also automatically leaves it compressed after writing any changes. If @var{dir-file} itself does not exist, @code{install-info} tries to open @file{@var{dir-file}.gz}, @file{@var{dir-file}.xz}, @file{@var{dir-file}.bz2}, @file{@var{dir-file}.lz}, and @file{@var{dir-file}.lzma}, in that order. Options: @table @code @item --add-once @opindex --add-once@r{, for @command{install-info}} Specifies that the entry or entries will only be put into a single section. @item --align=@var{column} @opindex --align=@var{column}@r{, for @command{install-info}} Specifies the column that the second and subsequent lines of menu entry's description will be formatted to begin at. The default for this option is @samp{35}. It is used in conjunction with the @samp{--max-width} option. @var{column} starts counting at 1. @item --append-new-sections @opindex --append-new-sections@r{, for @command{install-info}} Instead of alphabetizing new sections, place them at the end of the DIR file. @item --calign=@var{column} @opindex --calign=@var{column}@r{, for @command{install-info}} Specifies the column that the first line of menu entry's description will be formatted to begin at. The default for this option is @samp{33}. It is used in conjunction with the @samp{--max-width} option. When the name of the menu entry exceeds this column, entry's description will start on the following line. @var{column} starts counting at 1. @item --debug @opindex --debug@r{, for @command{install-info}} Report what is being done. @item --delete @opindex --delete@r{, for @command{install-info}} Delete the entries in @var{info-file} from @var{dir-file}. The file name in the entry in @var{dir-file} must be @var{info-file} (except for an optional @samp{.info} in either one). Don't insert any new entries. Any empty sections that result from the removal are also removed. @item --description=@var{text} @opindex --description=@var{text}@r{, for @command{install-info}} Specify the explanatory portion of the menu entry. If you don't specify a description (either via @samp{--entry}, @samp{--item} or this option), the description is taken from the Info file itself. @item --dir-file=@var{name} @opindex --dir-file=@var{name}@r{, for @command{install-info}} Specify file name of the Info directory file. This is equivalent to using the @var{dir-file} argument. @item --dry-run @opindex --dry-run@r{, for @command{install-info}} Same as @samp{--test}. @item --entry=@var{text} @opindex --entry=@var{text}@r{, for @command{install-info}} Insert @var{text} as an Info directory entry; @var{text} should have the form of an Info menu item line plus zero or more extra lines starting with whitespace. If you specify more than one entry, they are all added. If you don't specify any entries, they are determined from information in the Info file itself. @item --help @opindex --help@r{, for @command{texindex}} Display a usage message with basic usage and all available options, then exit successfully. @item --info-file=@var{file} @opindex --info-file=@var{file}@r{, for @command{install-info}} Specify Info file to install in the directory. This is equivalent to using the @var{info-file} argument. @item --info-dir=@var{dir} @opindex --info-dir=@var{dir}@r{, for @command{install-info}} Specify the directory where the directory file @file{dir} resides. Equivalent to @samp{--dir-file=@var{dir}/dir}. @item --infodir=@var{dir} @opindex --infodir=@var{dir}@r{, for @command{install-info}} Same as @samp{--info-dir}. @item --item=@var{text} @opindex --item=@var{text}@r{, for @command{install-info}} Same as @samp{--entry=@var{text}}. An Info directory entry is actually a menu item. @item --keep-old @opindex --keep-old@r{, for @command{install-info}} Do not replace pre-existing menu entries. When @samp{--remove} is specified, this option means that empty sections are not removed. @item --max-width=@var{column} @opindex --max-width=@var{column}@r{, for @command{install-info}} Specifies the column that the menu entry's description will be word-wrapped at. @var{column} starts counting at 1. @item --maxwidth=@var{column} @opindex --maxwidth=@var{column}@r{, for @command{install-info}} Same as @samp{--max-width}. @item --menuentry=@var{text} @opindex --menuentry=@var{text}@r{, for @command{install-info}} Same as @samp{--name}. @item --name=@var{text} @opindex --name=@var{text}@r{, for @command{install-info}} Specify the name portion of the menu entry. If the @var{text} does not start with an asterisk @samp{*}, it is presumed to be the text after the @samp{*} and before the parentheses that specify the Info file. Otherwise @var{text} is taken verbatim, and is taken as defining the text up to and including the first period (a space is appended if necessary). If you don't specify the name (either via @samp{--entry}, @samp{--item} or this option), it is taken from the Info file itself. If the Info does not contain the name, the basename of the Info file is used. @item --no-indent @opindex --no-indent@r{, for @command{install-info}} Suppress formatting of new entries into the @file{dir} file. @item --quiet @itemx --silent @opindex --quiet@r{, for @command{install-info}} @opindex --silent@r{, for @command{install-info}} Suppress warnings, etc., for silent operation. @item --remove @opindex --remove@r{, for @command{install-info}} Same as @samp{--delete}. @item --remove-exactly @opindex --remove-exactly@r{, for @command{install-info}} Also like @samp{--delete}, but only entries if the Info file name matches exactly; @code{.info} and/or @code{.gz} suffixes are @emph{not} ignored. @item --section=@var{sec} @opindex --section=@var{sec}@r{, for @command{install-info}} Put this file's entries in section @var{sec} of the directory. If you specify more than one section, all the entries are added in each of the sections. If you don't specify any sections, they are determined from information in the Info file itself. If the Info file doesn't specify a section, the menu entries are put into the Miscellaneous section. @item --section @var{regex} @var{sec} @opindex --section @var{regex} @var{sec}@r{, for @command{install-info}} Same as @samp{--regex=@var{regex} --section=@var{sec} --add-once}. @code{install-info} tries to detect when this alternate syntax is used, but does not always guess correctly. Here is the heuristic that @code{install-info} uses: @enumerate @item If the second argument to @code{--section} starts with a hyphen, the original syntax is presumed. @item If the second argument to @code{--section} is a file that can be opened, the original syntax is presumed. @item Otherwise the alternate syntax is used. @end enumerate When the heuristic fails because your section title starts with a hyphen, or it happens to be a file that can be opened, the syntax should be changed to @samp{--regex=@var{regex} --section=@var{sec} --add-once}. @item --regex=@var{regex} @opindex --regex=@var{regex}@r{, for @command{install-info}} Put this file's entries into any section that matches @var{regex}. If more than one section matches, all of the entries are added in each of the sections. Specify @var{regex} using basic regular expression syntax, more or less as used with @command{grep}, for example. @item --test @opindex --test@r{, for @command{install-info}} Suppress updating of the directory file. @item --version @opindex --version@r{, for @command{install-info}} @cindex Version number, for install-info Display version information and exit successfully. @end table @node Tag and Split Files @section Tag Files and Split Files @cindex Tag table @cindex nonsplit Info file @cindex split Info file Info files always contain a @dfn{tag table}, to be able to jump to nodes quickly. Info files can be @dfn{nonsplit} (also called @dfn{unsplit}) or @dfn{split}. @cindex Indirect subfiles If the Info file contains less than about 300,000 characters the file should be nonsplit. In that case, the tag table should appear at the end of the Info file. If the Texinfo file contains more than about 300,000 characters, Texinfo processors split the large Info file into shorter @dfn{indirect} subfiles of about 300,000 characters each. With @command{texi2any}, splitting may be prevented by @option{--no-split}, and the default size of 300,000 characters may be modified with @option{--split-size} (@pxref{Invoking @command{texi2any}}). When a file is split, Info itself makes use of a shortened version of the original file that contains just the tag table and references to the files that were split off. The split-off files are called @dfn{indirect} files. The split-off files have names that are created by appending @w{@samp{-1}}, @w{@samp{-2}}, @w{@samp{-3}} and so on to the output file name, specified by the @code{@@setfilename} command or the input file name. The shortened version of the original file continues to have the name specified by @code{@@setfilename} or the input file name. At one stage in writing this document, for example, the Info file was saved as the file @file{test-texinfo} and that file looked like this: @example @group Info file: test-texinfo, -*-Text-*- produced by texinfo-format-buffer from file: new-texinfo-manual.texinfo ^_ Indirect: test-texinfo-1: 102 test-texinfo-2: 50422 @end group @group test-texinfo-3: 101300 ^_^L Tag table: (Indirect) Node: overview^?104 Node: info file^?1271 @end group @group Node: printed manual^?4853 Node: conventions^?6855 @dots{} @end group @end example @noindent (But @file{test-texinfo} had far more nodes than are shown here.) Each of the split-off, indirect files, @file{test-texinfo-1}, @file{test-texinfo-2}, and @file{test-texinfo-3}, is listed in this file after the line that says @samp{Indirect:}. The tag table is listed after the line that says @samp{Tag table:}. In the list of indirect files, the number following the file name records the cumulative number of bytes in the preceding indirect files, not counting the file list itself, the tag table, or any permissions text in the first file. In the tag table, the number following the node name records the location of the beginning of the node, in bytes from the beginning of the (unsplit) output. If you are using @code{texinfo-format-buffer} to create Info files, you may want to run the @code{Info-validate} command. (The @command{texi2any} command does such a good job on its own, you do not need @code{Info-validate}.) However, you cannot run the @kbd{M-x Info-validate} node-checking command on indirect files. For information on how to prevent files from being split with @code{texinfo-format-buffer} and how to validate the structure of the nodes, see @ref{Using @code{Info-validate}}. @node Info Format FAQ @section Info Format FAQ Here are some questions that have been frequently asked on the project mailing lists and elsewhere. @table @asis @item Why when I run @samp{info @var{foo}} do I get the same output as @samp{man @var{foo}}? Check that the Info manuals are installed. Not all GNU/Linux distributions install all the Info manuals by default. This is regrettable, as often the Info manual provides more information than the provided man page. @item Why not use HTML instead of Info? Manuals are rarely written in the Info format itself, but are generated from Texinfo source by the @command{texi2any} program. @command{texi2any} can generate HTML as well as Info from Texinfo source. You can also access and download HTML manuals from the GNU website (@uref{https://www.gnu.org/manual/manual.html}). Additionally, some GNU/Linux distributions provide packages for the installation of HTML manuals. Info still has some advantages over HTML for locally installed documentation. The Info browsers support index lookup and support for links between locally installed manuals in multiple locations. It's important to have documentation installed locally on your machine rather than relying on the Internet; this makes accessing documentation more reliable, and ensures it matches installed versions of packages. It's hoped that support for browsing locally installed Texinfo documentation in some form of HTML can be improved in the future. @item Why provide the command-line @command{info} program when the Emacs Info reader is better? The Emacs Info reader can display images, and fully supports using a mouse. There are not many differences among the Info readers besides that. Command-line @command{info} can be configured to change the default key bindings, as well as change the color of cross-references and search results, and to enable mouse scrolling support. You should not need to be experienced with the Emacs editor to use @command{info}. (Some recommend another program called @command{pinfo}, but this lacks in important features like index lookup.) Some prefer to be able to scroll through the entire manual at once (as happens with man pages), rather than being limited to a single `node' of content at once. Of course, there is no accounting for taste, but a single, unstructured block of text becomes more awkward as a manual becomes longer and more complicated. (However, if you really want to, you can view an info manual all at once in the @command{less} pager with @samp{info @var{foo} | less}.) @item Why do I have `see' appearing in front of all of my links? By default, Emacs Info mode either changes the marker @samp{*note} for cross-references to `see', or hides it completely. Command-line @command{info} does the same if @code{hide-note-references} is set. Unfortunately, there is no way to do this reliably, as both the @code{@@pxref} and @code{@@ref} commands in Texinfo output this marker in the Info output, and the `see' text is only appropriate for @code{@@pxref}. @item Yes, but how do I get a plain link, with no extra markup? You can't. Info is a plain text format that is displayed mostly as-is in the viewers, and without the @samp{*note} text there would be nothing to mark text as a link. For output formats such as HTML, you can use the @code{@@link} command to produce a plain link. @xref{@code{@@link}}. This does not produce a working cross-reference in Info output or in a printed copy of the manual, though. @item Why do lines containing links appear mysteriously short? This due to Emacs (or @command{info} with @code{hide-note-references} set to @samp{On}) hiding @samp{*note} strings, as mentioned above. @item Can the Info format be extended to support fonts, colors or reflowable text? Any extension would be incompatible with existing Info-viewing programs. Extra markup added to Info files would be displayed to the user, making files ugly and unreadable. When Texinfo files are processed into Info files, information about which Texinfo commands were used to markup text is lost. Moreover, it is not possible to reliably detect whether text can be reflowed (e.g.@: a paragraph of prose), or whether line breaks should be kept (e.g.@: a code sample, or poem). Info's core purpose is to display documentation on text terminals. If you want more, you are recommended to use the HTML output from @command{texi2any} instead. @end table @node Generating HTML @nodedescription Details on HTML output. @chapter Generating HTML @cindex Generating HTML @cindex Outputting HTML @command{texi2any} generates Info output by default, but given the @option{--html} option, it will generate HTML, for web browsers and other programs. This chapter gives some details on such HTML output. @command{texi2any} has many user-definable customization variables with which you can influence the HTML output. @xref{Customization Variables}. In particular, there is support for syntax highlighting in @code{@@example} (@pxref{Syntax Highlighting}). You can also write so-called @dfn{initialization files}, or @dfn{init files} for short, to modify almost every aspect of HTML output formatting. Initialization files contain code and are loaded by @option{--init-file} (@pxref{Invoking @command{texi2any}}). Some initialization files are maintained with Texinfo and installed in the default case. For example, @file{chm.pm} produces the intermediate compressed HTML Help format files that can be subsequently converted to the CHM format. The documentation of @command{texi2any} HTML output adaptation using customization files is in a separate manual. @xref{,,, texi2any_api, GNU Texinfo @command{texi2any} Output Customization}. @node HTML Translation @nodedescription Details of the HTML output. @section HTML Translation @cindex HTML translation The HTML generated by @command{texi2any} generates standard HTML output. The output is intentionally quite plain for maximum portability and accessibility. You can customize the output via CSS (@pxref{HTML CSS}) or other means (@pxref{Customization Variables}). If you cannot accomplish a reasonable customization, feel free to report that. @cindex Navigation bar, in HTML output @strong{Navigation bar:} By default, a navigation bar is inserted at the start of each node, analogous to Info output. If the @samp{--no-headers} option is used, the navigation bar is only inserted at the beginning of split files. Header @code{<link>} elements in split output support Info-like navigation with browsers which implement this feature. @cindex Escaping to HTML @cindex Raw HTML @strong{Raw HTML}: @command{texi2any} will include segments of Texinfo source between @code{@@ifhtml} and @code{@@end ifhtml} in the HTML output (but not any of the other conditionals, by default). Source between @code{@@html} and @code{@@end html} is passed without change to the output (i.e., suppressing the normal escaping of input @samp{<}, @samp{>} and @samp{&} characters which have special significance in HTML)@. @xref{Conditional Commands}. @cindex HTML output, browser compatibility of @strong{Standards}: It is intentionally not our goal, and not even always possible, to pass through every conceivable validation test without any diagnostics. Different validation tests have different goals, often about pedantic enforcement of some standard or another. Our overriding goal is to help users, not blindly comply with standards. Please report output from an error-free run of @command{texi2any} which has @emph{practical} browser or EPUB reader portability problems as a bug (@pxref{Reporting Bugs}). In practice, the HTML produced by @command{texi2any} is slowly adjusted over time towards the latest HTML standard, while also trying to keep compatibility with earlier produced HTML. We use transitional markup and try to be slow enough to give time for the diverse HTML readers to adjust (and for standards to reincorporate useful features that were dropped@dots{}). @node HTML Splitting @nodedescription How HTML output is split. @section HTML Splitting @cindex Split HTML output @cindex HTML output, split When splitting output at nodes (which is the default), @command{texi2any} writes HTML output into (basically) one output file per Texinfo source @code{@@node}. Each output file name is the node name with spaces replaced by @samp{-}'s and special characters changed to @samp{_} followed by their code point in hex (@pxref{HTML Xref}). This is to make it portable and easy to use as a file name. In the unusual case of two different nodes having the same name after this treatment, they are written consecutively to the same file, with HTML anchors so each can be referred to independently. If @command{texi2any} is run on a system which does not distinguish case in file names, nodes which are the same except for case (e.g., @samp{index} and @samp{Index}) will also be folded into the same output file with anchors. You can also pretend to be on a case insensitive filesystem by setting the customization variable @code{CASE_INSENSITIVE_FILENAMES}. It is also possible to split at chapters or sections with @option{--split} (@pxref{Invoking @command{texi2any}}). In that case, the file names are constructed after the name of the node associated with the relevant sectioning command. Also, unless @option{--no-node-files} is specified, a redirection file is output for every node in order to more reliably support cross-references to that manual (@pxref{HTML Xref}). When splitting, the HTML output files are written into a subdirectory. The subdirectory name is derived from the base name (that is, any extension is removed), with @code{_html} postpended. For example, HTML output for @file{gcc.texi} would be written into a subdirectory named @samp{gcc_html/}. The subdirectory name is based on @code{@@setfilename} or on the input file name (@pxref{Setting the Output File Name}). @noindent In any case, the top-level output file within the directory is always named @samp{index.html}. Monolithic output (@code{--no-split}) is named according to @code{@@setfilename}, if present (with any @samp{.info} extension replaced with @samp{.html}), @code{--output} (the argument is used literally), or based on the input file name as a last resort (@pxref{Setting the Output File Name}). @node HTML CSS @nodedescription Influencing HTML output with Cascading Style Sheets. @section HTML CSS @cindex HTML, and CSS @cindex CSS, and HTML output @cindex Cascading Style Sheets, and HTML output Cascading Style Sheets (CSS) is an Internet standard for influencing the display of HTML documents: see @uref{http://www.w3.org/Style/CSS/}. By default, some CSS code is included to better implement the appearance of some Texinfo environments. For example: @example pre.display @{ font-family:inherit @} @end example The above tells the web browser to use the same font as the main document inside @samp{<pre>} elements used for @code{@@display} environments. By default, the HTML @samp{<pre>} command uses a monospaced font. Please see the reference above for a full explanation of CSS. You can influence the CSS in the HTML output with two @command{texi2any} options: @option{--css-include=@var{file}} and @option{--css-ref=@var{url}}. The option @option{--css-ref=@var{url}} adds to each output HTML file a @samp{<link>} tag referencing a CSS at the given @var{url}. This allows using external style sheets. The option @option{--css-include=@var{file}} includes the contents @var{file} in the HTML output, as you might expect. However, the details are somewhat tricky, as described in the following, to provide maximum flexibility. @cindex @samp{@@charset} specification, in CSS files The CSS file first line may be a @samp{@@charset} directive. If present, this directive is used to determine the encoding of the CSS file. The line is not copied into the output. @cindex @samp{@@import} specifications, in CSS files The CSS file may begin with so-called @samp{@@import} directives, which link to external CSS specifications for browsers to use when interpreting the document. Again, a full description is beyond our scope here, but we'll describe how they work syntactically, so we can explain how they are handled. @cindex Comments, in CSS files There can be more than one @samp{@@import}, but they have to come first in the file, with only whitespace and comments interspersed, no normal definitions. Comments in CSS files are delimited by @samp{/* ... */}, as in C@. An @samp{@@import} directive must be in one of these two forms: @example @@import url(http://example.org/foo.css); @@import "http://example.net/bar.css"; @end example The crucial characters are the @samp{@@} at the beginning and the semicolon terminating the directive. When reading the CSS file, any such @samp{@@}-directive is simply copied into the output, as follows: @itemize @item If @var{file} contains only normal CSS declarations, it is included after the default CSS, thus overriding it. @item If @var{file} begins with @samp{@@import} specifications (see below), then the @samp{import}'s are included first (they have to come first, according to the standard), and then the default CSS is included. If you need to override the default CSS from an @samp{@@import}, you can do so with the @samp{!@: important} CSS construct, as in: @example pre.example @{ font-size: inherit ! important @} @end example @item If @var{file} contains both @samp{@@import} and inline CSS specifications, the @samp{@@import}'s are included first, then default CSS, and lastly the inline CSS from @var{file}. @item Any @@-directive other than @samp{@@import} and @samp{@@charset} is treated as a CSS declaration, meaning the default CSS is included and then the rest of the file is prepended. @end itemize If the CSS file is malformed or erroneous, the output is unspecified. The meaning of the CSS file is not interpreted in any way; the special @samp{@@} and @samp{;} characters are looked for the text is blindly copied into the output. Comments in the CSS file may or may not be included in the output. In addition to the possibilities offered by CSS, @command{texi2any} has many user-definable customization variables with which you can influence the HTML output. @xref{Customization Variables}. @node @code{@@documentdescription} @nodedescription Document summary for the HTML output. @section @code{@@documentdescription}: Summary Text @anchor{documentdescription}@c old name @cindex Document description @cindex Description of document @cindex Summary of document @cindex Abstract of document @cindex @code{<meta>} HTML tag, and document description @findex documentdescription When producing HTML output for a document, a @samp{<meta>} element is written in the @samp{<head>} to give some idea of the content of the document. By default, this @dfn{description} is the title of the document, taken from the @code{@@settitle} command (@pxref{@code{@@settitle}}). To change this, use the @code{@@documentdescription} environment, as in: @example @@documentdescription descriptive text. @@end documentdescription @end example @noindent This will produce the following output in the @samp{<head>} of the HTML: @example <meta name=description content="descriptive text."> @end example @node Generating EPUB @nodedescription Details on the EPUB output. @section Generating EPUB @cindex EPUB, generating @cindex Generating EPUB @cindex Outputting EPUB EPUB is a format designed for reading electronic books on portable devices. @command{texi2any} generated EPUB 3.2 in 2022. An EPUB file is a ZIP archive container, holding informative files as well as the manual rendered in HTML. @cindex @code{Archive::Zip}, for EPUB file output @vindex EPUB_CREATE_CONTAINER_FILE @subentry @r{avoiding} @code{Archive::Zip} @r{dependency} The generation of the EPUB file depends on the @code{Archive::Zip} Perl module being installed. This dependency is checked at runtime. In the default case, trying to output EPUB without this dependency raises an error. However, if the EPUB output file is not generated, with the customization variable @code{EPUB_CREATE_CONTAINER_FILE} set to 0, it is not an error if @code{Archive::Zip} is not installed. The @command{texi2any} tests related to EPUB generation do not require the installation of @code{Archive::Zip}, as they set @code{EPUB_CREATE_CONTAINER_FILE} to 0 and keep the directory containing the files and directories needed for the EPUB file by setting the @code{EPUB_KEEP_CONTAINER_FOLDER} customization variable to 1. @node EPUB Output File and Directory @nodedescription Use syntax highlighting in code excerpts. @subsection Container Directory and Output Files @cindex Container directory for EPUB @cindex EPUB Container directory A directory containing the files and directories needed for the EPUB format is created when outputting EPUB. The name of this container directory is derived from the base name of the input file (that is, any extension is removed), with @code{_epub_package} postpended. If an output directory is specified, with @option{--output}, or with the @code{SUBDIR} customization variable, the container directory is created in that directory instead of the current directory. At the beginning of a new run, the container directory and all its contents are removed. The container directory is also removed after the final EPUB file has been generated in the default case. The HTML files produced from the Texinfo manual are output in subdirectories of the container directory. Image files referred to from the Texinfo manual, if found, are copied to subdirectories of the container directory. @cindex EPUB output file The EPUB output file is a ZIP archive of the container directory. The file name is derived from the base name, with the @code{.epub} extension postpended. If an output file is specified, with @option{--output}, or with the @code{OUTFILE} customization function, this file name is used instead. The output EPUB file is never placed in the directory specified by @option{--output} or @code{SUBDIR}; only the container directory is placed there, as explained just above. The EPUB output file is not generated if the customization variable @code{EPUB_CREATE_CONTAINER_FILE} is set to 0. The container directory is left after the final EPUB file has been generated if @code{EPUB_KEEP_CONTAINER_FOLDER} is set. @xref{Invoking @command{texi2any}}. @node EPUB Cross-References @nodedescription Cross-references in HTML output. @subsection EPUB Cross-References The EPUB format does not support references from an EPUB file to another EPUB file. Therefore any references to ``external'' Texinfo manuals should resolve to an external URL@:. @command{texi2any} produces these links with HTML cross-reference configuration (@pxref{HTML Xref Configuration}). Since the links in the resulting EPUB are incorrect if no information is found for the cross-references, @command{texi2any} issues a warning by default for missing cross-references information. If these warnings are unwanted, set @code{CHECK_HTMLXREF} to 0. @node EPUB HTML @subsection HTML Generated for EPUB The HTML generated for EPUB is XHTML conformant, UTF-8 encoded, and formatted without the usual HTML navigation headers and footers. Most of these features are enabled with customization variables, such as @code{USE_XML_SYNTAX} or @code{OUTPUT_FILE_NAME_ENCODING}. Some features of printed output are used in EPUB. In particular, the Top node does not appear in the EPUB output, while a title page is generated. This is obtained by setting @code{NO_TOP_NODE_OUTPUT}. The @code{OUTFILE} and @code{SUBDIR} customization variables values correspond initially to the EPUB directory container and/or the EPUB output file (@pxref{EPUB Output File and Directory}). These customization variables values are undefined or reset to the locations in the container directory where the XHTML files are output for the HTML generation. It is mentioned here because resetting customization variables is unusual; however, the variables reset are used internally for the conversion, and should not interact with any customization set by the user. @xref{HTML Customization Variables}. @node Syntax Highlighting @section Code Examples Syntax Highlighting in HTML @cindex @command{source-highlight} @cartouche @quotation warning Source highlighting is experimental, feedback is welcomed. @end quotation @end cartouche Support for source code syntax highlighting is available in @command{texi2any} for the HTML output, with the help of external software. This feature is turned on by setting @code{HIGHLIGHT_SYNTAX}. Source code highlighting is set up for @code{@@example} blocks. The language specified for syntax highlighting is the first argument on the @code{@@example} line (@pxref{@code{@@example}}), or @code{HIGHLIGHT_SYNTAX_DEFAULT_LANGUAGE} if set and there is no first argument. The @code{HIGHLIGHT_SYNTAX} value determines the command used for highlighting: @table @code @item highlight Use @command{highlight} from @url{http://www.andre-simon.de/doku/highlight/en/highlight.php}; @item pygments Use @command{pygmentize} from @url{https://pygments.org/}; @item anything else Use @command{source-highlight} (@pxref{,,,source-highlight, GNU Source-highlight}). @end table @xref{Other Customization Variables}. @node HTML Xref @section HTML Cross-references @cindex HTML cross-references @cindex Cross-references, in HTML output Cross-references between Texinfo manuals in HTML format become standard HTML @code{<a>} links. This section describes the algorithm used, so that Texinfo can cooperate with other programs, such as @command{texi2html}, by writing mutually compatible HTML files. This algorithm may or may not be used for links @emph{within} HTML output for a Texinfo file. Since no issues of compatibility arise in such cases, we do not need to specify this. We try to support references to such ``external'' manuals in both monolithic and split forms. A @dfn{monolithic} (mono) manual is entirely contained in one file, and a @dfn{split} manual has a file for each node. (@xref{HTML Splitting}.) @cindex Dumas, Patrice The algorithm was primarily devised by Patrice Dumas in 2003--04. @menu * Link Basics: HTML Xref Link Basics. * Node Expansion: HTML Xref Node Name Expansion. * Command Expansion: HTML Xref Command Expansion. * 8-bit Expansion: HTML Xref 8-bit Character Expansion. * Mismatch: HTML Xref Mismatch. * Configuration: HTML Xref Configuration. @end menu @node HTML Xref Link Basics @subsection HTML Cross-reference Link Basics @cindex HTML cross-references @subentry link basics For our purposes, an HTML link consists of four components: a host name, a directory part, a file part, and a target part. We always assume the @code{http} protocol. For example: @example http://@var{host}/@var{dir}/@var{file}.html#@var{target} @end example The information to construct a link comes from the node name and manual name in the cross-reference command in the Texinfo source (@pxref{Cross References}), and from @dfn{external information} (@pxref{HTML Xref Configuration}). We now consider each part in turn. The @var{host} is hardwired to be the local host. This could either be the literal string @samp{localhost}, or, according to the rules for HTML links, the @samp{http://localhost/} could be omitted entirely. The @var{dir} and @var{file} parts are more complicated, and depend on the relative split/mono nature of both the manual being processed and the manual that the cross-reference refers to. The underlying idea is that there is one directory for Texinfo manuals in HTML, and a given @var{manual} is either available as a monolithic file @file{@var{manual}.html}, or a split subdirectory @file{@var{manual}_html/*.html}. Here are the cases: @itemize @bullet @item If the present manual is split, and the referent manual is also split, the directory is @samp{../@var{referent}_html/} and the file is the expanded node name (described later). @item If the present manual is split, and the referent manual is mono, the directory is @samp{../} and the file is @file{@var{referent}.html}. @item If the present manual is mono, and the referent manual is split, the directory is @file{@var{referent}_html/} and the file is the expanded node name. @item If the present manual is mono, and the referent manual is also mono, the directory is @file{./} (or just the empty string), and the file is @file{@var{referent}.html}. @end itemize Another rule, that only holds for file names, is that base file names are truncated to 245 characters, to allow for an extension to be appended and still comply with the 255-character limit which is common to many filesystems. Although technically this can be changed with the @code{BASEFILENAME_LENGTH} customization variable (@pxref{Other Customization Variables}), doing so would make cross-manual references to such nodes invalid. Any directory part in the file name argument of the source cross reference command is ignored. Thus, @code{@@xref@{,,,../foo@}} and @code{@@xref@{,,,foo@}} both use @samp{foo} as the manual name. This is because any such attempted hardwiring of the directory is very unlikely to be useful for all the output formats that use the manual name. Finally, the @var{target} part is always the expanded node name. Whether the present manual is split or mono is determined by user option; @command{texi2any} defaults to split, with the @option{--no-split} option overriding this. Whether the referent manual is split or mono, however, is another bit of the external information (@pxref{HTML Xref Configuration}). By default, @command{texi2any} uses the same form of the referent manual as the present manual. Thus, there can be a mismatch between the format of the referent manual that the generating software assumes, and the format it's actually present in. @xref{HTML Xref Mismatch}. @node HTML Xref Node Name Expansion @subsection HTML Cross-reference Node Name Expansion @cindex HTML cross-references @subentry node name expansion @cindex node name expansion, in HTML cross-references @cindex expansion, of node names in HTML cross-references As mentioned in the previous section, the key part of the HTML cross reference algorithm is the conversion of node names in the Texinfo source into strings suitable for XHTML identifiers and file names. The restrictions are similar for each: plain ASCII letters, numbers, and the @samp{-} and @samp{_} characters are all that can be used. (Although HTML anchors can contain most characters, XHTML is more restrictive.) Cross-references in Texinfo can refer either to nodes, anchors (@pxref{@code{@@anchor}}) or float labels (@pxref{@code{@@float}}). However, anchors and float labels are treated identically to nodes in this context, so we'll continue to say ``node'' names for simplicity. A special exception: the Top node (@pxref{The Top Node}) is always mapped to the file @file{index.html}, to match web server software. However, the HTML @emph{target} is @samp{Top}. Thus (in the split case): @example @@xref@{Top,,, emacs, The GNU Emacs Manual@}. @result{} <a href="../emacs_html/index.html#Top"> @end example @enumerate @item The standard ASCII letters (a-z and A-Z) are not modified. All other characters may be changed as specified below. @item The standard ASCII numbers (0-9) are not modified except when a number is the first character of the node name. In that case, see below. @item Multiple consecutive space, tab and newline characters are transformed into just one space. @item Leading and trailing spaces are removed. @item After the above has been applied, each remaining space character is converted into a @samp{-} character. @item Other ASCII 7-bit characters are transformed into @samp{_00@var{xx}}, where @var{xx} is the ASCII character code in (lowercase) hexadecimal. This includes @samp{_}, which is mapped to @samp{_005f}. @item If the node name does not begin with a letter, the literal string @samp{g_t} is prefixed to the result. (Due to the rules above, that string can never occur otherwise; it is an arbitrary choice, standing for ``GNU Texinfo''.) This is necessary because XHTML requires that identifiers begin with a letter. @end enumerate For example: @example @@node A node --- with _'% @result{} A-node-_002d_002d_002d-with-_005f_0027_0025 @end example Example translations of common characters: @itemize @bullet @item @samp{_} @result{} @samp{_005f} @item @samp{-} @result{} @samp{_002d} @item @samp{A node} @result{} @samp{A-node} @end itemize On case-folding computer systems, nodes differing only by case will be mapped to the same file. In particular, as mentioned above, Top always maps to the file @file{index.html}. Thus, on a case-folding system, Top and a node named `Index' will both be written to @file{index.html}. Fortunately, the targets serve to distinguish these cases, since HTML target names are always case-sensitive, independent of operating system. @node HTML Xref Command Expansion @subsection HTML Cross-reference Command Expansion @cindex HTML cross-references @subentry command expansion Node names may contain @@-commands (@pxref{Node Line Requirements}). This section describes how they are handled. First, comments are removed. Next, any @code{@@value} commands (@pxref{@code{@@set @@value}}) and macro invocations (@pxref{Invoking Macros}) are fully expanded. Then, for the following commands, the command name and braces are removed, and the text of the argument is recursively transformed: @example @@asis @@b @@cite @@code @@command @@dfn @@dmn @@dotless @@emph @@env @@file @@i @@indicateurl @@kbd @@key @@samp @@sansserif @@sc @@slanted @@strong @@sub @@sup @@t @@U @@var @@verb @@w @end example In addition, the following commands are replaced by constant text, as shown below. If any of these commands have non-empty arguments, as in @code{@@TeX@{bad@}}, it is an error, and the result is unspecified. In this table, `(space)' means a space character and `(nothing)' means the empty string. The notation `U+@var{hhhh}' means Unicode code point @var{hhhh} (in hex, as usual). There are further transformations of many of these expansions to yield the final file or other target name, such as space characters to @samp{-}, etc., according to the other rules. @multitable @columnfractions .3 .5 @item @code{@@(newline)} @tab (space) @item @code{@@(space)} @tab (space) @item @code{@@(tab)} @tab (space) @item @code{@@!} @tab @samp{!} @item @code{@@*} @tab (space) @item @code{@@-} @tab (nothing) @item @code{@@.} @tab @samp{.} @item @code{@@:} @tab (nothing) @item @code{@@?} @tab @samp{?} @item @code{@@@@} @tab @samp{@@} @item @code{@@@{} @tab @samp{@{} @item @code{@@@}} @tab @samp{@}} @item @code{@@LaTeX} @tab @samp{LaTeX} @item @code{@@TeX} @tab @samp{TeX} @item @code{@@arrow} @tab U+2192 @item @code{@@bullet} @tab U+2022 @item @code{@@comma} @tab @samp{,} @item @code{@@copyright} @tab U+00A9 @item @code{@@dots} @tab U+2026 @item @code{@@enddots} @tab @samp{...} @item @code{@@equiv} @tab U+2261 @item @code{@@error} @tab @samp{error-->} @item @code{@@euro} @tab U+20AC @item @code{@@exclamdown} @tab U+00A1 @item @code{@@expansion} @tab U+21A6 @item @code{@@geq} @tab U+2265 @item @code{@@leq} @tab U+2264 @item @code{@@minus} @tab U+2212 @item @code{@@ordf} @tab U+00AA @item @code{@@ordm} @tab U+00BA @item @code{@@point} @tab U+22C6 @item @code{@@pounds} @tab U+00A3 @item @code{@@print} @tab U+22A3 @item @code{@@questiondown} @tab U+00BF @item @code{@@registeredsymbol} @tab U+00AE @item @code{@@result} @tab U+21D2 @item @code{@@textdegree} @tab U+00B0 @item @code{@@tie} @tab (space) @end multitable Quotation mark @@-commands (@code{@@quotedblright@{@}} and the like), are likewise replaced by their Unicode values. Normal quotation @emph{characters} (e.g., ASCII ` and ') are not altered. @xref{Inserting Quotation Marks}. Any @code{@@acronym}, @code{@@abbr}, @code{@@email}, and @code{@@image} commands are replaced by their first argument. (For these commands, all subsequent arguments are optional, and ignored here.) @xref{@code{@@acronym}}, and @ref{@code{@@email}}, and @ref{Images}. Accents are handled according to the next section. Any other command is an error, and the result is unspecified. @node HTML Xref 8-bit Character Expansion @subsection HTML Cross-reference 8-bit Character Expansion @cindex HTML cross-references @subentry 8-bit character expansion @cindex 8-bit characters, in HTML cross-references @cindex Expansion of 8-bit characters in HTML cross-references @cindex Transliteration of 8-bit characters in HTML cross-references Usually, characters other than plain 7-bit ASCII are transformed into the corresponding Unicode code point(s) in Normalization Form@tie{}C, which uses precomposed characters where available. (This is the normalization form recommended by the W3C and other bodies.) This holds when that code point is @code{0xffff} or less, as it almost always is. These will then be further transformed by the rules above into the string @samp{_@var{hhhh}}, where @var{hhhh} is the code point in hex. For example, combining this rule and the previous section: @example @@node @@b@{A@} @@TeX@{@} @@u@{B@} @@point@{@}@@enddots@{@} @result{} A-TeX-B_0306-_22C6_002e_002e_002e @end example Notice: 1)@tie{}@code{@@enddots} expands to three periods which in turn expands to three @samp{_002e}'s; 2)@tie{}@code{@@u@{B@}} is a `B' with a breve accent, which does not exist as a pre-accented Unicode character, therefore expands to @samp{B_0306} (B with combining breve). When the Unicode code point is above @code{0xffff}, the transformation is @samp{__@var{xxxxxx}}, that is, two leading underscores followed by six hex digits. Since Unicode has declared that their highest code point is @code{0x10ffff}, this is sufficient. (We felt it was better to define this extra escape than to always use six hex digits, since the first two would nearly always be zeros.) This method works fine if the node name consists mostly of ASCII characters and contains only few 8-bit ones. But if the document is written in a language whose script is not based on the Latin alphabet (for example, Ukrainian), it will create file names consisting almost entirely of @samp{_@var{xxxx}} notations, which is inconvenient and all but unreadable. To handle such cases, @command{texi2any} offers the @option{--transliterate-file-names} command line option. This option enables @dfn{transliteration} of node names into ASCII characters for the purposes of file name creation and referencing. The transliteration is based on phonetic principles, which makes the generated file names more easily understandable. @cindex Normalization Form C, Unicode For the definition of Unicode Normalization Form@tie{}C, see Unicode report UAX#15, @uref{http://www.unicode.org/reports/tr15/}. Many related documents and implementations are available elsewhere on the web. @node HTML Xref Mismatch @subsection HTML Cross-reference Mismatch @cindex HTML cross-references @subentry mismatch @cindex Mismatched HTML cross-reference source and target As mentioned earlier (@pxref{HTML Xref Link Basics}), the generating software may need to guess whether a given manual being cross-referenced is available in split or monolithic form---and, inevitably, it might guess wrong. However, when the @emph{referent} manual is generated, it is possible to handle at least some mismatches. In the case where we assume the referent is split, but it is actually available in mono, the only recourse would be to generate a @file{manual_html/} subdirectory full of HTML files which redirect back to the monolithic @file{manual.html}. Since this is essentially the same as a split manual in the first place, it's not very appealing. On the other hand, in the case where we assume the referent is mono, but it is actually available in split, it is possible to use JavaScript to redirect from the putatively monolithic @file{manual.html} to the different @file{manual_html/node.html} files. Here's an example: @example function redirect() @{ switch (location.hash) @{ case "#Node1": location.replace("manual_html/Node1.html#Node1"); break; case "#Node2" : location.replace("manual_html/Node2.html#Node2"); break; @dots{} default:; @} @} @end example Then, in the @code{<body>} tag of @file{manual.html}: @example <body onLoad="redirect();"> @end example Once again, this is something the software which generated the @emph{referent} manual has to do in advance, it's not something the software generating the cross-reference in the present manual can control. @node HTML Xref Configuration @nodedescription @file{htmlxref.cnf}. @subsection HTML Cross-reference Configuration: @file{htmlxref.cnf} @pindex htmlxref.cnf @cindex HTML cross-references @subentry configuration @cindex Cross-reference configuration, for HTML @cindex Configuration, for HTML cross-manual references @command{texi2any} reads a file named @file{htmlxref.cnf} to gather information for cross-references to other manuals in HTML output. It is looked for in the following directories: @table @file @item ./ (the current directory) @item ./.texinfo/ (under the current directory) @item ~/.texinfo/ (where @code{~} is the current user's home directory) @item @var{sysconfdir}/texinfo/ (where @var{sysconfdir} is the system configuration directory specified at compile-time, e.g., @file{/usr/local/etc}) @item @var{datadir}/texinfo/ (likewise specified at compile time, e.g., @file{/usr/local/share}) @end table All files found are used, with earlier entries overriding later ones. The Texinfo distribution includes a default file which handles many GNU manuals; it is installed in the last of the above directories, i.e., @file{@var{datadir}/texinfo/htmlxref.cnf}. The @code{HTMLXREF_MODE} customization variable can be set to modify how the files are found. For instance, if set to @samp{none}, no external information is used. @code{HTMLXREF_FILE} sets the file name to something else than @file{htmlxref.cnf}. @pxref{HTML Customization Variables}. The file is line-oriented. Lines consisting only of whitespace are ignored. Comments are indicated with a @samp{#} at the beginning of a line, optionally preceded by whitespace. Since @samp{#} can occur in URLs (like almost any character), it does not otherwise start a comment. Each non-blank non-comment line must be either a @dfn{variable assignment} or @dfn{manual information}. A variable assignment line looks like this: @example @var{varname} = @var{varvalue} @end example Whitespace around the @samp{=} is optional and ignored. The @var{varname} should consist of letters; case is significant. The @var{varvalue} is an arbitrary string, continuing to the end of the line. Variables are then referenced with @samp{$@{@var{varname}@}}; variable references can occur in the @var{varvalue}. A manual information line looks like this: @example @var{manual} @var{keyword} @var{urlprefix} @end example @noindent with @var{manual} the short identifier for a manual, @var{keyword} being one of: @code{mono}, @code{node}, @code{section}, @code{chapter}, and @var{urlprefix} described below. Variable references can occur only in the @var{urlprefix}. For example (used in the canonical @file{htmlxref.cnf}): @example G = http://www.gnu.org GS = $@{G@}/software hello mono $@{GS@}/hello/manual/hello.html hello chapter $@{GS@}/hello/manual/html_chapter/ hello section $@{GS@}/hello/manual/html_section/ hello node $@{GS@}/hello/manual/html_node/ @end example @cindex monolithic manuals, for HTML cross-references If the keyword is @code{mono}, @var{urlprefix} gives the host, directory, and file name for @var{manual} as one monolithic file. @cindex split manuals, for HTML cross-references If the keyword is @code{node}, @code{section}, or @code{chapter}, @var{urlprefix} gives the host and directory for @var{manual} split into nodes, sections, or chapters, respectively. When available, @command{texi2any} will use the ``corresponding'' value for cross-references between manuals. That is, when generating monolithic output (@option{--no-split}), the @code{mono} URL will be used, when generating output that is split by node, the @code{node} URL will be used, etc. However, if a manual is not available in that form, anything that is available can be used. Here is the search order for each style: @example node @result{} node, section, chapter, mono section @result{} section, chapter, node, mono chapter @result{} chapter, section, node, mono mono @result{} mono, chapter, section, node @end example @opindex --node-files@r{, and HTML cross-references} These section- and chapter-level cross-manual references can succeed only when the target manual was created using @option{--node-files}; this is the default for split output. If you have additions or corrections to the @file{htmlxref.cnf} distributed with Texinfo, please email @email{bug-texinfo@@gnu.org} as usual. You can get the latest version from @url{http://ftpmirror.gnu.org/@/texinfo/@/htmlxref.cnf}. @node @@-Command Details @nodedescription Details of the Texinfo @@-commands. @appendix @@-Command Details Here are the details of @@-commands: information about their syntax, a list of commands, and information about where commands can appear. @node Command Syntax @section @@-Command Syntax @cindex @sortas{at} @@-commands @subentry syntax @cindex Syntax, of @@-commands @cindex Command syntax Texinfo has the following types of @@-command: @table @asis @item 1. Brace commands These commands start with @@ followed by a letter or a word, followed by an argument within braces. For example, the command @code{@@dfn} indicates the introductory or defining use of a term; it is used as follows: @samp{In Texinfo, @@@@-commands are @@dfn@{mark-up@} commands.} @item 2. Line commands These commands occupy an entire line. The line starts with @@, followed by the name of the command (a word); for example, @code{@@center} or @code{@@cindex}. If no argument is needed, the word is followed by the end of the line. If there is an argument, it is separated from the command name by a space. Braces are not used. @findex end @item 3. Block commands These commands are written at the start of a line, with general text on following lines, terminated by a matching @code{@@end} command on a line of its own. For example, @code{@@example}, then the lines of a coding example, then @code{@@end example}. Some of these block commands take arguments as line commands do; for example, @code{@@enumerate A} opening an environment terminated by @code{@@end enumerate}. Here @samp{A} is the argument. @item 4. Symbol insertion commands with no arguments These commands start with @@ followed by a word followed by a left and right- brace. These commands insert special symbols in the document; they do not take arguments. Some examples: @code{@@dots@{@}} @result{} @samp{@dots{}}, @code{@@equiv@{@}} @result{} @samp{@equiv{}}, @code{@@TeX@{@}} @result{} `@TeX{}', and @code{@@bullet@{@}} @result{} @samp{@bullet{}}. @item 5. Non-alphabetic commands The names of commands in all of the above categories consist of alphabetic characters, almost entirely in lower-case. Unlike those, the non-alphabetic commands consist of an @@ followed by a punctuation mark or other character that is not part of the Latin alphabet. Non-alphabetic commands are almost always part of text within a paragraph. The non-alphabetic commands include @code{@@@@}, @code{@@@{}, @code{@@@}}, @code{@@.}, @code{@@@kbd{SPACE}}, and most of the accent commands. @item 6. Miscellaneous commands There are a handful of commands that don't fit into any of the above categories; for example, the obsolete command @code{@@refill}, which is always used at the end of a paragraph immediately following the final period or other punctuation character. @code{@@refill} takes no argument and does not require braces. Likewise, @code{@@tab} used in a @code{@@multitable} block does not take arguments, and is not followed by braces. @end table @cindex Braces and argument syntax Thus, the alphabetic commands fall into classes that have different argument syntaxes. You cannot tell to which class a command belongs by the appearance of its name, but you can tell by the command's meaning: if the command stands for a glyph, it is in class 4 and does not require an argument; if it makes sense to use the command among other text as part of a paragraph, the command is in class 1 and must be followed by an argument in braces. The non-alphabetic commands, such as @code{@@:}, are exceptions to the rule; they do not need braces. The purpose of having different syntax for commands is to make Texinfo files easier to read, and also to help the GNU Emacs paragraph and filling commands work properly. @node Command List @section @@-Command List @cindex Alphabetical @@-command list @cindex List of @@-commands @cindex @sortas{at} @@-commands @subentry list of @cindex Reference to @@-commands Here is an alphabetical list of the @@-commands in Texinfo. Square brackets, @t{[}@w{ }@t{]}, indicate optional arguments; an ellipsis, @samp{@dots{}}, indicates repeated text. @table @code @item @@@var{whitespace} An @code{@@} followed by a space, tab, or newline produces a normal, stretchable, interword space. @xref{Multiple Spaces}. @item @@! Produce an exclamation point that ends a sentence (usually after an end-of-sentence capital letter). @xref{Ending a Sentence}. @item @@" @itemx @@' Generate an umlaut or acute accent, respectively, over the next character, as in @"o and @'o. @xref{Inserting Accents}. @item @@& @itemx @@ampchar@{@} Generate an ampersand. @xref{Inserting an Ampersand}. @item @@* Force a line break. @xref{Line Breaks}. @item @@,@{@var{c}@} Generate a cedilla accent under @var{c}, as in @,{c}. @xref{Inserting Accents}. @item @@- Insert a discretionary hyphenation point. @xref{@code{@@- @@hyphenation}}. @item @@. Produce a period that ends a sentence (usually after an end-of-sentence capital letter). @xref{Ending a Sentence}. @item @@/ Produces no output, but allows a line break. @xref{Line Breaks}. @item @@: Tell printed output processors to refrain from inserting extra whitespace after an immediately preceding period, question mark, exclamation mark, or colon. @xref{Not Ending a Sentence}. @item @@= Generate a macron (bar) accent over the next character, as in @=o. @xref{Inserting Accents}. @item @@? Produce a question mark that ends a sentence (usually after an end-of-sentence capital letter). @xref{Ending a Sentence}. @item @@@@ @itemx @@atchar@{@} Insert an at sign, @samp{@@}. @xref{Inserting an Atsign}. @item @@\ @itemx @@backslashchar@{@} Insert a backslash, @samp{\}; @code{@@backslashchar@{@}} works anywhere, while @code{@@\} works only inside @code{@@math}. @xref{Inserting a Backslash}, and @ref{Inserting Math}. @item @@^ @itemx @@` Generate a circumflex (hat) or grave accent, respectively, over the next character, as in @^o and @`e. @xref{Inserting Accents}. @item @@@{ @itemx @@lbracechar@{@} Insert a left brace, @samp{@{}. @xref{Inserting Braces}. @item @@@} @itemx @@rbracechar@{@} Insert a right brace, @samp{@}}. @xref{Inserting Braces}. @item @@~ Generate a tilde accent over the next character, as in @~N. @xref{Inserting Accents}. @item @@AA@{@} @itemx @@aa@{@} Generate the uppercase and lowercase Scandinavian A-ring letters, respectively: @AA{}, @aa{}. @xref{Inserting Accents}. @item @@abbr@{@var{abbreviation}@} Indicate a general abbreviation, such as `Comput.'. @xref{@code{@@abbr}}. @item @@acronym@{@var{acronym}@} Indicate an acronym in all capital letters, such as `NASA'. @xref{@code{@@acronym}}. @item @@AE@{@} @itemx @@ae@{@} Generate the uppercase and lowercase AE ligatures, respectively: @AE{}, @ae{}. @xref{Inserting Accents}. @item @@afivepaper Change page dimensions for the A5 paper size. @xref{A4 Paper}. @item @@afourlatex @itemx @@afourpaper @itemx @@afourwide Change page dimensions for the A4 paper size. @xref{A4 Paper}. @item @@alias @var{new}=@var{existing} Make the command @samp{@@@var{new}} a synonym for the existing command @samp{@@@var{existing}}. @xref{@code{@@alias}}. @item @@allowcodebreaks @var{true-false} Control breaking at @samp{-} and @samp{_} in printed output. @xref{@code{@@allowcodebreaks}}. @item @@anchor@{@var{name}@} Define @var{name} as the current location for use as a cross-reference target. @xref{@code{@@anchor}}. @item @@appendix @var{title} Begin an appendix. The title appears in the table of contents. @xref{@code{@@unnumbered @@appendix}}. @item @@appendixsec @var{title} @itemx @@appendixsection @var{title} Begin an appendix section within an appendix. The section title appears in the table of contents. @code{@@appendixsection} is a longer spelling of the @code{@@appendixsec} command. @xref{@code{@@unnumberedsec @@appendixsec @@heading}}. @item @@appendixsubsec @var{title} Begin an appendix subsection. The title appears in the table of contents. @xref{@code{@@unnumberedsubsec @@appendixsubsec @@subheading}}. @item @@appendixsubsubsec @var{title} Begin an appendix subsubsection. The title appears in the table of contents. @xref{@code{@@subsubsection}}. @item @@arrow@{@} Generate a right arrow glyph: @samp{@arrow{}}. Used by default for @code{@@click}. @xref{Click Sequences}. @item @@asis Keep the argument as is. Used following @code{@@table}, @code{@@ftable}, and @code{@@vtable} to print the table's first column without highlighting (``as is''). @xref{@code{@@asis}}. @item @@author @var{author} Set a manual author in the title page. @xref{@code{@@title @@subtitle @@author}}. Set a quotation author in @code{@@quotation}. @xref{@code{@@quotation}}. @item @@b@{@var{text}@} Set @var{text} in a @b{bold} font, if possible. @xref{Fonts}. @item @@bullet@{@} Generate a large round dot, @bullet{}, or the closest possible thing to one. Often used with @code{@@table}. @xref{@code{@@bullet}}. @item @@bsixpaper Change page dimensions for the B6 paper size. @xref{A4 Paper}. @item @@bye Stop processing a file. The processors do not see anything in the input file following @code{@@bye}. @xref{Ending a File}. @item @@c @var{comment} Begin a comment in Texinfo. The rest of the line does not appear in any output. A synonym for @code{@@comment}. @kbd{DEL} also starts a comment. @xref{Comments}. @item @@caption Define the full caption for a @code{@@float}. @xref{@code{@@caption @@shortcaption}}. @item @@cartouche Highlight an example or quotation by drawing a box with rounded corners around it, if possible. Pair with @code{@@end cartouche}. @xref{@code{@@cartouche}}. @item @@center @var{line-of-text} Center the line of text following the command. @xref{@code{@@titlefont @@center @@sp}}. @item @@centerchap @var{line-of-text} Like @code{@@chapter}, but centers the chapter title. @xref{@code{@@chapter}}. @item @@chapheading @var{title} Print an unnumbered chapter-like heading, but omit from the table of contents. @xref{@code{@@majorheading @@chapheading}}. @item @@chapter @var{title} Begin a numbered chapter. The chapter title appears in the table of contents. @xref{@code{@@chapter}}. @item @@cindex @var{entry} Add @var{entry} to the index of concepts. @xref{Index Entries, , Defining the Entries of an Index}. @item @@cite@{@var{reference}@} Highlight the name of a book or other reference that has no companion Info file. @xref{@code{@@cite}}. @item @@clear @var{flag} Unset @var{flag}, preventing the Texinfo formatting commands from formatting text between subsequent pairs of @code{@@ifset @var{flag}} and @code{@@end ifset} commands, and preventing @code{@@value@{@var{flag}@}} from expanding to the value to which @var{flag} is set. @xref{@code{@@set @@clear @@value}}. @item @@click@{@} Represent a single ``click'' in a GUI@. Used within @code{@@clicksequence}. @xref{Click Sequences}. @item @@clicksequence@{@var{action} @@click@{@} @var{action}@} Represent a sequence of clicks in a GUI@. @xref{Click Sequences}. @item @@clickstyle @@@var{cmd} Execute @@@var{cmd} for each @code{@@click}; the default is @code{@@arrow}. The usual following empty braces on @@@var{cmd} are omitted. @xref{Click Sequences}. @item @@code@{@var{sample-code}@} Indicate an expression, a syntactically complete token of a program, or a program name. @xref{@code{@@code}}. @item @@codequotebacktick @var{on-off} @itemx @@codequoteundirected @var{on-off} Control output of @code{`} and @code{'} in code examples. @xref{Inserting Quote Characters}. @item @@comma@{@} Insert a comma `,' character; only needed when a literal comma would be taken as an argument separator. @xref{Inserting a Comma}. @item @@command@{@var{command-name}@} Indicate a command name, such as @command{ls}. @xref{@code{@@command}}. @item @@comment @var{comment} Begin a comment in Texinfo. The rest of the line does not appear in any output. A synonym for @code{@@c}. @xref{Comments}. @item @@contents Print a complete table of contents or specify that a table of content should be output, for formats that may output a table of contents. @xref{Contents, , Generating a Table of Contents}. @item @@copying Specify copyright holders and copying conditions for the document. Pair with @code{@@end copying}. @xref{@code{@@copying}}. @item @@copyright@{@} Generate the copyright symbol @copyright{}. @xref{@code{@@copyright}}. @item @@defblock Start a block containing definitions. Pair with @samp{@@end defblock}. @xref{Generic Definition Commands}. @item @@defcodeindex @var{index-name} Define a new index and its indexing command. Print entries in an @code{@@code} font. @xref{New Indices, , Defining New Indices}. @item @@defcv @var{category} @var{class} @var{name} @itemx @@defcvx @var{category} @var{class} @var{name} Format a description for a variable associated with a class in object-oriented programming. Takes three arguments: the category of thing being defined, the class to which it belongs, and its name. @xref{Definition Commands}. @item @@deffn @var{category} @var{name} @var{arguments}@dots{} @itemx @@deffnx @var{category} @var{name} @var{arguments}@dots{} Format a description for a function, interactive command, or similar entity that may take arguments. @code{@@deffn} takes as arguments the category of entity being described, the name of this particular entity, and its arguments, if any. @xref{Definition Commands}. @item @@defindex @var{index-name} Define a new index and its indexing command. Print entries in a roman font. @xref{New Indices, , Defining New Indices}. @item @@definfoenclose @var{newcmd}, @var{before}, @var{after} Create a new command @code{@@@var{newcmd}} for online formats that marks text by enclosing it in strings that precede and follow the text. @xref{@code{@@definfoenclose}}. @item @@defivar @var{class} @var{instance-variable-name} @itemx @@defivarx @var{class} @var{instance-variable-name} Format a description for an instance variable in object-oriented programming. The command is equivalent to @samp{@@defcv @{Instance Variable@} @dots{}}. @xref{Definition Commands}. @item @@defline @var{category} @var{name} @var{arguments}@dots{} Use within a @code{@@defblock} environment to give the heading prototype line for a symbol being defined. This command does not create any index entries. @xref{Generic Definition Commands}. @item @@defmac @var{macroname} @var{arguments}@dots{} @itemx @@defmacx @var{macroname} @var{arguments}@dots{} Format a description for a macro; equivalent to @samp{@@deffn Macro @dots{}}. @xref{Definition Commands}. @item @@defmethod @var{class} @var{method-name} @var{arguments}@dots{} @itemx @@defmethodx @var{class} @var{method-name} @var{arguments}@dots{} Format a description for a method in object-oriented programming; equivalent to @samp{@@defop Method @dots{}}. @xref{Definition Commands}. @item @@defop @var{category} @var{class} @var{name} @var{arguments}@dots{} @itemx @@defopx @var{category} @var{class} @var{name} @var{arguments}@dots{} Format a description for an operation in object-oriented programming. @code{@@defop} takes as arguments the name of the category of operation, the name of the operation's class, the name of the operation, and its arguments, if any. @xref{Definition Commands}, and @ref{Abstract Objects}. @item @@defopt @var{option-name} @itemx @@defoptx @var{option-name} Format a description for a user option; equivalent to @samp{@@defvr @{User Option@} @dots{}}. @xref{Definition Commands}. @item @@defspec @var{special-form-name} @var{arguments}@dots{} @itemx @@defspecx @var{special-form-name} @var{arguments}@dots{} Format a description for a special form; equivalent to @samp{@@deffn @{Special Form@} @dots{}}. @xref{Definition Commands}. @item @@deftp @var{category} @var{name-of-type} @var{attributes}@dots{} @itemx @@deftpx @var{category} @var{name-of-type} @var{attributes}@dots{} Format a description for a data type; its arguments are the category, the name of the type (e.g., @samp{int}) , and then the names of attributes of objects of that type. @xref{Definition Commands}, and @ref{Data Types}. @item @@deftypecv @var{category} @var{class} @var{data-type} @var{name} @itemx @@deftypecvx @var{category} @var{class} @var{data-type} @var{name} Format a description for a typed class variable in object-oriented programming. @xref{Definition Commands}, and @ref{Abstract Objects}. @item @@deftypefn @var{category} @var{data-type} @var{name} @var{arguments}@dots{} @itemx @@deftypefnx @var{category} @var{data-type} @var{name} @var{arguments}@dots{} Format a description for a function or similar entity that may take arguments and that is typed. @code{@@deftypefn} takes as arguments the category of entity being described, the type, the name of the entity, and its arguments, if any. @xref{Definition Commands}. @item @@deftypefnnewline @var{on-off} Specifies whether return types for @code{@@deftypefn} and similar are printed on lines by themselves; default is off. @xref{Typed Functions,, Functions in Typed Languages}. @item @@deftypefun @var{data-type} @var{function-name} @var{arguments}@dots{} @itemx @@deftypefunx @var{data-type} @var{function-name} @var{arguments}@dots{} Format a description for a function in a typed language. The command is equivalent to @samp{@@deftypefn Function @dots{}}. @xref{Definition Commands}. @item @@deftypeivar @var{class} @var{data-type} @var{variable-name} @itemx @@deftypeivarx @var{class} @var{data-type} @var{variable-name} Format a description for a typed instance variable in object-oriented programming. @xref{Definition Commands}, and @ref{Abstract Objects}. @item @@deftypeline @var{category} @var{data-type} @var{name} @var{arguments}@dots{} Use within a @code{@@defblock} environment to give the heading prototype line for a symbol being defined, with data types. This command does not create any index entries. @xref{Generic Definition Commands}. @item @@deftypemethod @var{class} @var{data-type} @var{method-name} @var{arguments}@dots{} @itemx @@deftypemethodx @var{class} @var{data-type} @var{method-name} @var{arguments}@dots{} Format a description for a typed method in object-oriented programming. @xref{Definition Commands}. @item @@deftypeop @var{category} @var{class} @var{data-type} @var{name} @var{arguments}@dots{} @itemx @@deftypeopx @var{category} @var{class} @var{data-type} @var{name} @var{arguments}@dots{} Format a description for a typed operation in object-oriented programming. @xref{Definition Commands}, and @ref{Abstract Objects}. @item @@deftypevar @var{data-type} @var{variable-name} @itemx @@deftypevarx @var{data-type} @var{variable-name} Format a description for a variable in a typed language. The command is equivalent to @samp{@@deftypevr Variable @dots{}}. @xref{Definition Commands}. @item @@deftypevr @var{category} @var{data-type} @var{name} @itemx @@deftypevrx @var{category} @var{data-type} @var{name} Format a description for something like a variable in a typed language---an entity that records a value. Takes as arguments the category of entity being described, the type, and the name of the entity. @xref{Definition Commands}. @item @@defun @var{function-name} @var{arguments}@dots{} @itemx @@defunx @var{function-name} @var{arguments}@dots{} Format a description for a function; equivalent to @samp{@@deffn Function @dots{}}. @xref{Definition Commands}. @item @@defvar @var{variable-name} @itemx @@defvarx @var{variable-name} Format a description for a variable; equivalent to @samp{@@defvr Variable @dots{}}. @xref{Definition Commands}. @item @@defvr @var{category} @var{name} @itemx @@defvrx @var{category} @var{name} Format a description for any kind of variable. @code{@@defvr} takes as arguments the category of the entity and the name of the entity. @xref{Definition Commands}. @item @@detailmenu Mark the (optional) detailed node listing in a master menu. @xref{Master Menu Parts}. @item @@dfn@{@var{term}@} Indicate the introductory or defining use of a term. @xref{@code{@@dfn}}. @item @@DH@{@} @itemx @@dh@{@} Generate the uppercase and lowercase Icelandic letter eth, respectively: @DH{}, @dh{}. @xref{Inserting Accents}. @item @@dircategory @var{dirpart} Specify a category for the manual. @xref{Directory Category}. @item @@direntry Begin the Info directory menu entry for this file. Pair with @code{@@end direntry}. @xref{Installing Dir Entries}. @item @@display Begin a kind of example. Like @code{@@example} (indent text, do not fill), but do not select a new font. Pair with @code{@@end display}. @xref{@code{@@display}}. @item @@displaymath Format a block of math in ``display'' format. @xref{Inserting Math}. @item @@dmn@{@var{dimension}@} Format a unit of measure, as in 12@dmn{pt}. @xref{@code{@@dmn}}. @item @@docbook Enter DocBook completely. Pair with @code{@@end docbook}. @xref{Raw Formatter Commands}. @item @@documentdescription Set the document description text, included in the HTML output. Pair with @code{@@end documentdescription}. @xref{@code{@@documentdescription}}. @item @@documentencoding @var{enc} Declare the input encoding to be @var{enc}. @xref{@code{@@documentencoding}}. @item @@documentlanguage @var{CC} Declare the document language as the two-character ISO-639 abbreviation @var{CC}. @xref{@code{@@documentlanguage}}. @item @@dotaccent@{@var{c}@} Generate a dot accent over the character @var{c}, as in @dotaccent{o}. @xref{Inserting Accents}. @item @@dotless@{@var{i-or-j}@} Generate dotless i (`@dotless{i}') and dotless j (`@dotless{j}'). @xref{Inserting Accents}. @item @@dots@{@} Generate an ellipsis, @samp{@dots{}}. @xref{@code{@@dots}}. @item @@email@{@var{address}[, @var{displayed-text}]@} Indicate an electronic mail address. @xref{@code{@@email}}. @item @@emph@{@var{text}@} Emphasize @var{text}. @xref{Emphasis, , Emphasizing Text}. @item @@end @var{environment} Ends @var{environment}, as in @samp{@@end example}. @xref{Formatting Commands,,@@-commands}. @item @@enddots@{@} Generate an end-of-sentence ellipsis, like this: @enddots{} @xref{@code{@@dots}}. @item @@enumerate [@var{number-or-letter}] Begin a numbered list, using @code{@@item} for each entry. Optionally, start list with @var{number-or-letter}. Pair with @code{@@end enumerate}. @xref{@code{@@enumerate}}. @item @@env@{@var{environment-variable}@} Indicate an environment variable name, such as @env{PATH}. @xref{@code{@@env}}. @item @@equiv@{@} Indicate to the reader the exact equivalence of two forms with a glyph: @samp{@equiv{}}. @xref{@code{@@equiv}}. @item @@error@{@} Indicate to the reader with a glyph that the following text is an error message: @samp{@error{}}. @xref{@code{@@error}}. @item @@errormsg@{@var{msg}@} Report @var{msg} as an error to standard error, and exit unsuccessfully. Texinfo commands within @var{msg} are expanded to plain text. @xref{Conditionals}, and @ref{External Macro Processors}. @item @@euro@{@} Generate the Euro currency sign. @xref{@code{@@euro}}. @item @@evenfooting [@var{left}] @@| [@var{center}] @@| [@var{right}] @itemx @@evenheading [@var{left}] @@| [@var{center}] @@| [@var{right}] Specify page footings resp.@: headings for even-numbered (left-hand) pages. @xref{Custom Headings, , How to Make Your Own Headings}. @item @@everyfooting [@var{left}] @@| [@var{center}] @@| [@var{right}] @itemx @@everyheading [@var{left}] @@| [@var{center}] @@| [@var{right}] Specify page footings resp.@: headings for every page. Not relevant to Info. @xref{Custom Headings, , How to Make Your Own Headings}. @item @@example Begin an example. Indent text, do not fill, and select fixed-width font. Pair with @code{@@end example}. @code{@@example} accepts optional arguments, separated by commas. It is recommended to set the first argument to the language of the example code. @xref{@code{@@example}}. @item @@exampleindent @var{indent} Indent example-like environments by @var{indent} number of spaces (perhaps 0). @xref{@code{@@exampleindent}}. @item @@exclamdown@{@} Generate an upside-down exclamation point. @xref{Inserting Accents}. @item @@exdent @var{line-of-text} Remove any indentation a line might have. @xref{@code{@@exdent}}. @item @@expansion@{@} Indicate the result of a macro expansion to the reader with a special glyph: @samp{@expansion{}}. @xref{@code{@@expansion}}. @item @@file@{@var{filename}@} Highlight the name of a file, buffer, node, directory, etc. @xref{@code{@@file}}. @item @@finalout Prevent @TeX{} from printing large black warning rectangles beside over-wide lines. @xref{Overfull hboxes}. @item @@findex @var{entry} Add @var{entry} to the index of functions. @xref{Index Entries, , Defining the Entries of an Index}. @item @@firstparagraphindent @var{word} Control indentation of the first paragraph after section headers according to @var{word}, one of `none' or `insert'. @xref{@code{@@firstparagraphindent}}. @item @@float Environment to define floating material. Pair with @code{@@end float}. @xref{Floats}. @item @@flushleft @itemx @@flushright Do not fill text; left (right) justify every line while leaving the right (left) end ragged. Leave font as is. Pair with @code{@@end flushleft} (@code{@@end flushright}). @xref{@code{@@flushleft @@flushright}}. @item @@fonttextsize @var{10-11} Change the size of the main body font in the printed output. @xref{Fonts}. @item @@footnote@{@var{text-of-footnote}@} Enter a footnote, for a reference that documents or elucidates the primary text. Footnote text is printed at the bottom of the page in printed output. In other formats, footnote text can be output in the same node, in a separate node, or simply be marked as being footnote text. @xref{Footnotes}. @item @@footnotestyle @var{style} Specify a footnote style, either @samp{end} for the end node style or @samp{separate} for the separate style. In the separate style, footnotes are put in a separate node or file. @xref{Footnote Styles}. @item @@format Begin a kind of example. Like @code{@@display}, but do not indent. Pair with @code{@@end format}. @xref{@code{@@example}}. @item @@frenchspacing @var{on-off} Control spacing after punctuation. @xref{@code{@@frenchspacing}}. @item @@ftable @var{formatting-command} Begin a two-column table, using @code{@@item} for each entry. Automatically enter each of the items in the first column into the index of functions. Pair with @code{@@end ftable}. The same as @code{@@table}, except for indexing. @xref{@code{@@ftable @@vtable}}. @item @@geq@{@} Generate a greater-than-or-equal sign, `@geq{}'. @xref{@code{@@geq @@leq}}. @item @@group Disallow page breaks within following text. Pair with @code{@@end group}. Ignored in Info. @xref{@code{@@group}}. @item @@guillemetleft@{@} @itemx @@guillemetright@{@} @item @@guillemotleft@{@} @itemx @@guillemotright@{@} @itemx @@guilsinglleft@{@} @itemx @@guilsinglright@{@} Double and single angle quotation marks: @guillemetleft{} @guillemetright{} @guilsinglleft{} @guilsinglright{}. @code{@@guillemotleft} and @code{@@guillemotright} are synonyms for @code{@@guillemetleft} and @code{@@guillemetright}. @xref{Inserting Quotation Marks}. @item @@H@{@var{c}@} Generate the long Hungarian umlaut accent over @var{c}, as in @H{o}. @item @@hashchar@{@} Insert a hash `#' character; only needed when a literal hash would introduce @code{#line} directive. @xref{Inserting a Hashsign}, and @ref{External Macro Processors}. @item @@heading @var{title} Print an unnumbered section-like heading, but omit from the table of contents. @xref{@code{@@unnumberedsec @@appendixsec @@heading}}. @item @@headings @var{on-off-single-double} Turn page headings on or off, and/or specify single-sided or double-sided page headings for printing. @xref{@code{@@headings}}. @item @@headitem Begin a heading row in a multitable. @xref{Multitable Rows}. @item @@headitemfont@{@var{text}@} Set @var{text} in the font used for multitable heading rows; mostly useful in multitable templates. @xref{Multitable Rows}. @item @@html Enter HTML completely. Pair with @code{@@end html}. @xref{Raw Formatter Commands}. @item @@hyphenation@{@var{hy-phen-a-ted words}@} Explicitly define hyphenation points. @xref{@code{@@- @@hyphenation}}. @item @@i@{@var{text}@} Set @var{text} in an @i{italic} font, when possible. @xref{Fonts}. @item @@ifclear @var{txivar} If the Texinfo variable @var{txivar} is not set, format the following text. Pair with @code{@@end ifclear}. @xref{@code{@@set @@clear @@value}}. @item @@ifcommanddefined @var{txicmd} @itemx @@ifcommandnotdefined @var{txicmd} If the Texinfo code @samp{@@@var{txicmd}} is (not) defined, format the follow text. Pair with the corresponding @code{@@end ifcommand...}. @xref{Testing for Texinfo Commands}. @item @@ifdocbook @itemx @@ifhtml @itemx @@ifinfo @itemx @@iflatex @itemx @@ifplaintext @itemx @@ifxml Begin text that will appear only in the given output format. @code{@@ifinfo} output appears in both Info and (for historical compatibility) plain text output. Pair with @code{@@end ifdocbook} resp.@: @code{@@end ifhtml}@enddots{} @xref{Conditionals}. @item @@ifnotdocbook @itemx @@ifnothtml @itemx @@ifnotlatex @itemx @@ifnotplaintext @itemx @@ifnottex @itemx @@ifnotxml Begin text to be ignored in one output format but not the others. @code{@@ifnothtml} text is omitted from HTML output, etc. Pair with the corresponding @code{@@end ifnot@var{format}}. @xref{Conditionals}. @item @@ifnotinfo Begin text to appear in output other than Info and (for historical compatibility) plain text. Pair with @code{@@end ifnotinfo}. @xref{Conditionals}. @item @@ifset @var{txivar} If the Texinfo variable @var{txivar} is set, format the following text. Pair with @code{@@end ifset}. @xref{@code{@@set @@clear @@value}}. @item @@iftex Begin text to appear only in the @TeX{} output. Pair with @code{@@end iftex}. @xref{Conditionals}. @item @@ignore Begin text that will not appear in any output. Pair with @code{@@end ignore}. @xref{Comments, , Comments and Ignored Text}. @item @@image@{@var{filename}, [@var{width}], [@var{height}], [@var{alt}], [@var{ext}]@} Include graphics image in external @var{filename} scaled to the given @var{width} and/or @var{height}, using @var{alt} text and looking for @samp{@var{filename}.@var{ext}} in HTML@. @xref{Images}. @item @@include @var{filename} Read the contents of Texinfo source file @var{filename}. @xref{Include Files}. @item @@indent Insert paragraph indentation. @xref{@code{@@indent}}. @item @@indentedblock Indent a block of arbitrary text on the left. Pair with @code{@@end indentedblock}. @xref{@code{@@indentedblock}}. @item @@indicateurl@{@var{indicateurl}@} Indicate text that is a uniform resource locator for the World Wide Web. @xref{@code{@@indicateurl}}. @item @@inforef@{@var{node-name}, [@var{entry-name}], @var{info-file-name}@} Make a cross-reference to an Info file for which there is no printed manual. @xref{@code{@@inforef}}. @item @@inlinefmt@{@var{fmt}, @var{text}@} Insert @var{text} only if the output format is @var{fmt}. @xref{Inline Conditionals}. @item @@inlinefmtifelse@{@var{fmt}, @var{text}, @var{else-text}@} Insert @var{text} if the output format is @var{fmt}, else @var{else-text}. @item @@inlineifclear@{@var{var}, @var{text}@} @itemx @@inlineifset@{@var{var}, @var{text}@} Insert @var{text} only if the Texinfo variable @var{var} is (not) set. @item @@inlineraw@{@var{fmt}, @var{raw-text}@} Insert @var{text} as in a raw conditional, only if the output format is @var{fmt}. @item \input @var{macro-definitions-file} Use the specified macro definitions file. This command is used only in the first line of a Texinfo file to cause @TeX{} to make use of the @file{texinfo} macro definitions file. The @code{\} in @code{\input} is used instead of an @code{@@} because @TeX{} does not recognize @code{@@} until after it has read the definitions file. @xref{Texinfo File Header}. @item @@insertcopying Insert the text previously defined with the @code{@@copying} environment. @xref{@code{@@insertcopying}}. @item @@item Indicate the beginning of a marked paragraph for @code{@@itemize} and @code{@@enumerate}; indicate the beginning of the text of a first column entry for @code{@@table}, @code{@@ftable}, and @code{@@vtable}. @xref{Lists and Tables}. @item @@itemize @var{mark-generating-character-or-command} Begin an unordered list: indented paragraphs with a mark, such as @code{@@bullet}, inside the left margin at the beginning of each item. Pair with @code{@@end itemize}. @xref{@code{@@itemize}}. @item @@itemx Like @code{@@item} in @code{@@table}, @code{@@ftable}, and @code{@@vtable}, but do not generate extra vertical space above the item text. Thus, when several items have the same description, use @code{@@item} for the first and @code{@@itemx} for the others. @xref{@code{@@itemx}}. @item @@kbd@{@var{keyboard-characters}@} Indicate characters of input to be typed by users. @xref{@code{@@kbd}}. @item @@kbdinputstyle @var{style} Specify when @code{@@kbd} should use a font distinct from @code{@@code} according to @var{style}: @code{code}, @code{distinct}, @code{example}. @xref{@code{@@kbd}}. @item @@key@{@var{key-name}@} Indicate the name of a key on a keyboard. @xref{@code{@@key}}. @item @@kindex @var{entry} Add @var{entry} to the index of keys. @xref{Index Entries, , Defining the Entries of an Index}. @item @@L@{@} @itemx @@l@{@} Generate the uppercase and lowercase Polish suppressed-L letters, respectively: @L{}, @l{}. @item @@LaTeX@{@} Generate the @LaTeX{} logo. @xref{@code{@@TeX @@LaTeX}}. @item @@latex Enter @LaTeX{} completely. Pair with @code{@@end latex}. @xref{Raw Formatter Commands}. @item @@leq@{@} Generate a less-than-or-equal sign, `@leq{}'. @xref{@code{@@geq @@leq}}. @item @@linemacro @var{macroname} @{@var{params}@} Define a new macro which takes rest of the line as an argument, and expands to a whole number of complete lines. @xref{Line Macros}. @item @@link@{@var{nodename}, @var{label}, @var{manual-name}@} Create a plain link with no visible markup or page reference. @xref{@code{@@link}}. @item @@lisp Begin an example of Lisp code. Indent text, do not fill, and select fixed-width font. Pair with @code{@@end lisp}. @xref{@code{@@lisp}}. @item @@listoffloats Produce a table-of-contents-like listing of @code{@@float}s. @xref{@code{@@listoffloats}}. @item @@lowersections Change subsequent chapters to sections, sections to subsections, and so on. @xref{Raise/lower sections, , @code{@@raisesections} and @code{@@lowersections}}. @item @@macro @var{macroname} @{@var{params}@} Define a new Texinfo command @code{@@@var{macroname}@{@var{params}@}}. Pair with @code{@@end macro}. @xref{Defining Macros}. @item @@majorheading @var{title} Print an unnumbered chapter-like heading, but omit from the table of contents. This generates more vertical whitespace before the heading than the @code{@@chapheading} command. @xref{@code{@@majorheading @@chapheading}}. @item @@math@{@var{mathematical-expression}@} Format a mathematical expression. @xref{Inserting Math}. @item @@menu Mark the beginning of a menu of nodes. No effect in a printed manual. Pair with @code{@@end menu}. @xref{Menus}. @item @@microtype @var{on-off} Turn microtype on or off. @xref{Microtypography}. @item @@minus@{@} Generate a minus sign, `@minus{}'. @xref{@code{@@minus}}. @item @@multitable @var{column-width-spec} Begin a multi-column table. Begin each row with @code{@@item} or @code{@@headitem}, and separate columns with @code{@@tab}. Pair with @code{@@end multitable}. @xref{Multitable Column Widths}. @item @@need @var{n} Start a new page in a printed manual if fewer than @var{n} mils (thousandths of an inch) remain on the current page. @xref{@code{@@need}}. @item @@node @var{name}, [@var{next}], [@var{previous}], [@var{up}] Begin a new node. Only the first argument is mandatory. @xref{Writing a Node}. @item @@nodedescription @var{node-description} Provide a short elaboration of the purpose of a node. @xref{Node Descriptions}. @item @@nodedescriptionblock Used to start a longer node description. Pair with @samp{@@end nodedescriptionblock}. @xref{Node Descriptions}. @item @@noindent Prevent text from being indented as if it were a new paragraph. @xref{@code{@@noindent}}. @item @@novalidate Suppress validation of node references and omit creation of auxiliary files with @TeX{}. Use before any sectioning or cross-reference commands. @xref{Pointer Validation}. @item @@O@{@} @itemx @@o@{@} Generate the uppercase and lowercase O-with-slash letters, respectively: @O{}, @o{}. @item @@oddfooting [@var{left}] @@| [@var{center}] @@| [@var{right}] @itemx @@oddheading [@var{left}] @@| [@var{center}] @@| [@var{right}] Specify page footings resp.@: headings for odd-numbered (right-hand) pages. @xref{Custom Headings, , How to Make Your Own Headings}. @item @@OE@{@} @itemx @@oe@{@} Generate the uppercase and lowercase OE ligatures, respectively: @OE{}, @oe{}. @xref{Inserting Accents}. @item @@ogonek@{@var{c}@} Generate an ogonek diacritic under the next character, as in @ogonek{a}. @xref{Inserting Accents}. @item @@option@{@var{option-name}@} Indicate a command-line option, such as @option{-l} or @option{--help}. @xref{@code{@@option}}. @item @@ordf@{@} @itemx @@ordm@{@} Generate the feminine and masculine Spanish ordinals, respectively: @ordf{}, @ordm{}. @xref{Inserting Accents}. @item @@page Start a new page in a printed manual. @xref{@code{@@page}}. @item @@pagesizes [@var{width}][, @var{height}] Change page dimensions. @xref{pagesizes}. @item @@paragraphindent @var{indent} Indent paragraphs by @var{indent} number of spaces (perhaps 0); preserve source file indentation if @var{indent} is @code{asis}. @xref{@code{@@paragraphindent}}. @item @@part @var{title} Begin a group of chapters or appendixes; included in the tables of contents. @xref{@code{@@part}}. @item @@pindex @var{entry} Add @var{entry} to the index of programs. @xref{Index Entries, , Defining the Entries of an Index}. @item @@point@{@} Indicate the position of point in a buffer to the reader with a glyph: @samp{@point{}}. @xref{@code{@@point}}. @item @@pounds@{@} Generate the pounds sterling currency sign, @samp{@pounds{}}. @xref{@code{@@pounds}}. @item @@print@{@} Indicate printed output to the reader with a glyph: @samp{@print{}}. @xref{@code{@@print}}. @item @@printindex @var{index-name} Generate the index for @var{index-name}. @xref{Printing Indices & Menus}. @item @@pxref@{@var{node}, [@var{entry}], [@var{node-title}], [@var{info-file}], [@var{printed-manual}]@} Make a reference to be used within parentheses. Starts with a lowercase `see' in a printed manual. The first argument is mandatory, except for references to whole manuals. To refer to another manual as a whole, the @var{printed-manual} and/or the @var{info-file} are the only required arguments. @xref{@code{@@pxref}}. @item @@questiondown@{@} Generate an upside-down question mark. @xref{Inserting Accents}. @item @@quotation Narrow the margins to indicate text that is quoted from another work. Takes optional argument specifying prefix text. Pair with @code{@@end quotation}. @xref{@code{@@quotation}}. @item @@quotedblleft@{@} @itemx @@quotedblright@{@} @itemx @@quoteleft@{@} @itemx @@quoteright@{@} @itemx @@quotedblbase@{@} @itemx @@quotesinglbase@{@} Produce various quotation marks: @quotedblleft{} @quotedblright{} @quoteleft{} @quoteright{} @quotedblbase{} @quotesinglbase{}. @xref{Inserting Quotation Marks}. @item @@r@{@var{text}@} Set @var{text} in the regular @r{roman} font, if possible. @xref{Fonts}. @item @@raggedright Fill text; left justify every line while leaving the right end ragged. Leave font as is. Pair with @code{@@end raggedright}. @xref{@code{@@raggedright}}. @item @@raisesections Change subsequent sections to chapters, subsections to sections, and so on. @xref{Raise/lower sections}. @item @@ref@{@var{node}, [@var{entry}], [@var{node-title}], [@var{info-file}], [@var{printed-manual}]@} Make a plain reference that does not start with any special text. Follow command with a punctuation mark. The first argument is mandatory, except for references to whole manuals. To refer to another manual as a whole, the @var{printed-manual} and/or the @var{info-file} are the only required arguments. @xref{@code{@@ref}}. @item @@registeredsymbol@{@} Generate the legal symbol @registeredsymbol{}. @xref{@code{@@registeredsymbol}}. @item @@result@{@} Indicate the result of an expression to the reader with a special glyph: @samp{@result{}}. @xref{@code{@@result}}. @item @@ringaccent@{@var{c}@} Generate a ring accent over the next character, as in @ringaccent{o}. @xref{Inserting Accents}. @item @@samp@{@var{text}@} Indicate a literal example of a sequence of characters, in general. @xref{@code{@@samp}}. @item @@sansserif@{@var{text}@} Set @var{text} in a @sansserif{sans serif} font if possible. @xref{Fonts}. @item @@sc@{@var{text}@} Set @var{text} in a small caps font if possible, and uppercase in Info. @xref{Smallcaps}. @item @@section @var{title} Begin a section within a chapter. The section title appears in the table of contents. Within @code{@@chapter} and @code{@@appendix}, the section title is numbered; within @code{@@unnumbered}, the section is unnumbered. @xref{@code{@@section}}. @item @@seealso@{@var{index-text}@} Use in an index entry to refer the reader to another relevant index entry. @xref{Advanced Indexing}. @item @@seeentry@{@var{index-text}@} Use in an index entry to redirect the reader to another index entry. @xref{Advanced Indexing}. @item @@set @var{txivar} [@var{string}] Define the Texinfo variable @var{txivar}, optionally to the value @var{string}. @xref{@code{@@set @@clear @@value}}. @item @@setchapternewpage @var{on-off-odd} Specify whether chapters start on new pages, and if so, whether on odd-numbered (right-hand) new pages. @xref{@code{@@setchapternewpage}}. @item @@setfilename @var{info-file-name} Provide a name to be used for the output files. This command is ignored for @TeX{} formatting. @xref{@code{@@setfilename}}. @item @@settitle @var{title} Specify the title for page headers in a printed manual, and the default document title for HTML. @xref{@code{@@settitle}}. @item @@shortcaption Define the short caption for a @code{@@float}. @xref{@code{@@caption @@shortcaption}}. @item @@shortcontents Print a short table of contents, with chapter-level entries only, or specify that a short table of contents should be output. For formats that may output a short table of contents. @xref{Contents, , Generating a Table of Contents}. @item @@shorttitlepage @var{title} Generate a minimal title page. @xref{@code{@@titlepage}}. @item @@slanted@{@var{text}@} Set @var{text} in a @slanted{slanted} font if possible. @xref{Fonts}. @item @@smallbook In printed output, use a 7 by 9.25 inch format rather than the regular 8.5 by 11 inch format. @xref{@code{@@smallbook}}. @item @@smalldisplay Begin a kind of example. Like @code{@@display}, but use a smaller font size where possible. Pair with @code{@@end smalldisplay}. @xref{small}. @item @@smallexample Begin an example. Like @code{@@example}, but use a smaller font size where possible. Pair with @code{@@end smallexample}. @xref{small}. @item @@smallformat Begin a kind of example. Like @code{@@format}, but use a smaller font size where possible. Pair with @code{@@end smallformat}. @xref{small}. @item @@smallindentedblock Like @code{@@indentedblock}, but use a smaller font size where possible. Pair with @code{@@end smallindentedblock}. @xref{small}. @item @@smalllisp Begin an example of Lisp code. Same as @code{@@smallexample}. Pair with @code{@@end smalllisp}. @xref{small}. @item @@smallquotation Like @code{@@quotation}, but use a smaller font size where possible. Pair with @code{@@end smallquotation}. @xref{small}. @item @@sortas @{@var{key}@} Used in the arguments to index commands to give a string by which the index entry should be sorted. @xref{Indexing Commands}. @item @@sp @var{n} Skip @var{n} blank lines. @xref{@code{@@sp}}. @item @@ss@{@} Generate the German sharp-S es-zet letter, @ss{}. @xref{Inserting Accents}. @item @@strong @{@var{text}@} Emphasize @var{text} more strongly than @code{@@emph}. @xref{emph & strong, , Emphasizing Text}. @item @@sub @{@var{text}@} Set @var{text} as a subscript. @xref{Inserting Subscripts and Superscripts}. @item @@subentry Use in an index entry to separate parts of a multi-level entry. @xref{Advanced Indexing}. @item @@subheading @var{title} Print an unnumbered subsection-like heading, but omit from the table of contents of a printed manual. @xref{@code{@@unnumberedsubsec @@appendixsubsec @@subheading}}. @item @@subsection @var{title} Begin a subsection within a section. The subsection title appears in the table of contents. Same context-dependent numbering as @code{@@section}. @xref{@code{@@subsection}}. @item @@subsubheading @var{title} Print an unnumbered subsubsection-like heading, but omit from the table of contents of a printed manual. @xref{@code{@@subsubsection}}. @item @@subsubsection @var{title} Begin a subsubsection within a subsection. The subsubsection title appears in the table of contents. Same context-dependent numbering as @code{@@section}. @xref{@code{@@subsubsection}}. @item @@subtitle @var{title} Set a subtitle for the title page. @xref{@code{@@title @@subtitle @@author}}. @item @@summarycontents Print or specify a short table of contents. Synonym for @code{@@shortcontents}. @xref{Contents, , Generating a Table of Contents}. @item @@sup @{@var{text}@} Set @var{text} as a superscript. @xref{Inserting Subscripts and Superscripts}. @item @@syncodeindex @var{from-index} @var{to-index} Merge the index named in the first argument into the index named in the second argument, formatting the entries from the first index with @code{@@code}. @xref{Combining Indices}. @item @@synindex @var{from-index} @var{to-index} Merge the index named in the first argument into the index named in the second argument. Do not change the font of @var{from-index} entries. @xref{Combining Indices}. @item @@t@{@var{text}@} Set @var{text} in a @t{fixed-width}, typewriter-like font, if possible. @xref{Fonts}. @item @@tab Separate columns in a row of a multitable. @xref{Multitable Rows}. @item @@table @var{formatting-command} Begin a two-column table (description list), using @code{@@item} for each entry. Write each first column entry on the same line as @code{@@item}. First column entries are printed in the font resulting from @var{formatting-command}. Pair with @code{@@end table}. @xref{Two-column Tables, , Making a Two-column Table}. Also see @ref{@code{@@ftable @@vtable}}, and @ref{@code{@@itemx}}. @item @@TeX@{@} Generate the @TeX{} logo. @xref{@code{@@TeX @@LaTeX}}. @item @@tex Enter @TeX{} completely. Pair with @code{@@end tex}. @xref{Raw Formatter Commands}. @item @@textdegree@{@} Generate the degree symbol. @xref{@code{@@textdegree}}. @item @@thischapter @itemx @@thischaptername @itemx @@thischapternum @itemx @@thissection @itemx @@thissectionname @itemx @@thissectionnum @itemx @@thisfile @itemx @@thispage @itemx @@thistitle Only allowed in a heading or footing. Stands for, respectively, the number and name of the current chapter (in the format `Chapter 1: Title'), the current chapter name only, the current chapter number only, the number and name of the current section, the current section name only, the current section number only, the file name, the current page number, and the title of the document. @xref{Custom Headings,, How to Make Your Own Headings}. @item @@TH@{@} @itemx @@th@{@} Generate the uppercase and lowercase Icelandic letter thorn, respectively: @TH{}, @th{}. @xref{Inserting Accents}. @item @@tie@{@} Generate a normal interword space at which a line break is not allowed. @xref{@code{@@tie}}. @item @@tieaccent@{@var{cc}@} Generate a tie-after accent over the next two characters @var{cc}, as in `@tieaccent{oo}'. @xref{Inserting Accents}. @item @@tindex @var{entry} Add @var{entry} to the index of data types. @xref{Index Entries, , Defining the Entries of an Index}. @item @@title @var{title} Set the title for the title page. @xref{@code{@@title @@subtitle @@author}}. @item @@titlefont@{@var{text}@} Print @var{text} in a larger than normal font, if possible. @xref{@code{@@titlefont @@center @@sp}}. @item @@titlepage Begin the title page. Write the command on a line of its own, paired with @code{@@end titlepage}. The title page is not output, in the default case, in online formats. @xref{@code{@@titlepage}}. @item @@today@{@} Insert the current date, in `1 Jan 1900' style. @xref{Custom Headings, , How to Make Your Own Headings}. @item @@top @var{title} Mark the topmost @code{@@node} in the file, which must be defined on the line immediately preceding the @code{@@top} command. The title is formatted as a chapter-level heading. In @TeX{} the @code{@@top} command is merely a synonym for @code{@@unnumbered}. @item @@U@{@var{hex}@} Output a representation of Unicode character U+@var{hex}. @xref{Inserting Unicode}. @item @@u@{@var{c}@} @itemx @@ubaraccent@{@var{c}@} @itemx @@udotaccent@{@var{c}@} Generate a breve, underbar, or underdot accent, respectively, over or under the character @var{c}, as in @u{o}, @ubaraccent{o}, @udotaccent{o}. @xref{Inserting Accents}. @item @@unmacro @var{macroname} Undefine the macro @code{@@@var{macroname}} if it has been defined. @xref{Defining Macros}. @item @@unnumbered @var{title} Begin a chapter that appears without chapter numbers of any kind. The title appears in the table of contents. @xref{@code{@@unnumbered @@appendix}}. @item @@unnumberedsec @var{title} Begin a section that appears without section numbers of any kind. The title appears in the table of contents. @xref{@code{@@unnumberedsec @@appendixsec @@heading}}. @item @@unnumberedsubsec @var{title} Begin an unnumbered subsection. The title appears in the table of contents. @xref{@code{@@unnumberedsubsec @@appendixsubsec @@subheading}}. @item @@unnumberedsubsubsec @var{title} Begin an unnumbered subsubsection. The title appears in the table of contents. @xref{@code{@@subsubsection}}. @item @@uref@{@var{url}[, @var{displayed-text}][, @var{replacement}@} @itemx @@url@{@var{url}[, @var{displayed-text}][, @var{replacement}@} Define a cross-reference to an external uniform resource locator, e.g., for the World Wide Web. @xref{@code{@@url}}. @item @@urefbreakstyle @var{style} Specify how @code{@@uref}/@code{@@url} should break at special characters: @code{after}, @code{before}, @code{none}. @xref{@code{@@url}}. @item @@v@{@var{c}@} Generate check accent over the character @var{c}, as in @v{o}. @xref{Inserting Accents}. @item @@value@{@var{txivar}@} Insert the value, if any, of the Texinfo variable @var{txivar}, previously defined by @code{@@set}. @xref{@code{@@set @@clear @@value}}. @item @@var@{@var{metasyntactic-variable}@} Highlight a metasyntactic variable, which is something that stands for another piece of text. @xref{@code{@@var}}. @item @@verb@{@var{delim} @var{literal} @var{delim}@} Output @var{literal}, delimited by the single character @var{delim}, exactly as is (in the fixed-width font), including any whitespace or Texinfo special characters. @xref{@code{@@verb}}. @item @@verbatim Output the text of the environment exactly as is (in the fixed-width font). Pair with @code{@@end verbatim}. @xref{@code{@@verbatim}}. @item @@verbatiminclude @var{filename} Output the contents of @var{filename} exactly as is (in the fixed-width font). @xref{@code{@@verbatiminclude}}. @item @@vindex @var{entry} Add @var{entry} to the index of variables. @xref{Index Entries, , Defining the Entries of an Index}. @item @@vskip @var{amount} In a printed manual, insert whitespace so as to push text on the remainder of the page towards the bottom of the page. Used in formatting the copyright page with the argument @samp{0pt plus 1filll}. (Note spelling of @samp{filll}.) @xref{Copyright}. @item @@vtable @var{formatting-command} Begin a two-column table, using @code{@@item} for each entry. Automatically enter each of the items in the first column into the index of variables. Pair with @code{@@end vtable}. The same as @code{@@table}, except for indexing. @xref{@code{@@ftable @@vtable}}. @item @@w@{@var{text}@} Disallow line breaks within @var{text}. @xref{@code{@@w}}. @item @@xml Enter XML completely. Pair with @code{@@end xml}. @xref{Raw Formatter Commands}. @item @@xref@{@var{node}, [@var{entry}], [@var{node-title}], [@var{info-file}], [@var{printed-manual}]@} Make a reference that starts with `See' in a printed manual. Follow command with a punctuation mark. The first argument is mandatory, except for references to whole manuals. To refer to another manual as a whole, the @var{printed-manual} and/or the @var{info-file} are the only required arguments. @xref{@code{@@xref}}. @item @@xrefautomaticsectiontitle @var{on-off} By default, use the section title instead of the node name in cross references, including in node headers in HTML. @xref{Three Arguments}. @end table @node Command Contexts @section @@-Command Contexts @cindex Contexts, of @@-commands Here we describe approximately which @@-commands can be used in which contexts. It is not exhaustive or meant to be a complete reference. Discrepancies between the information here and the Texinfo processors implementations are most likely to be resolved in favor of the implementations. By @dfn{general text} below, we mean anything except sectioning and other such outer-level document commands, such as @code{@@section}, @code{@@node}, and @code{@@setfilename}. @code{@@c}, @code{@@comment} and @code{@@if ... @@end if} conditional commands may appear anywhere (except the conditionals must still be on lines by themselves). @code{@@caption} and @code{@@shortcaption} may only appear in @code{@@float} but may contain general text. @code{@@footnote} content likewise. @@-commands with braces marking text (such as @code{@@strong}, @code{@@sc}, @code{@@asis}) may contain raw formatter commands such as @code{@@html} but no other block commands (other commands terminated by @code{@@end}) and may not be split across paragraphs, but may otherwise contain general text. In addition to the block command restriction, on @code{@@center}, @code{@@exdent} and @code{@@item} in @code{@@table} lines, @@-commands that makes only sense in a paragraph are not accepted, such as @code{@@indent}. In addition to the above, sectioning commands cannot contain @code{@@anchor}, @code{@@footnote} or @code{@@verb}. In addition to the above, remaining commands (@code{@@node}, @code{@@anchor}, @code{@@printindex}, @code{@@ref}, @code{@@math}, @code{@@cindex}, @code{@@url}, @code{@@image}, and so on) cannot contain cross-reference commands (@code{@@ref}, @code{@@xref}, @code{@@pxref} and @code{@@inforef}). For precise and complete information, we suggest looking into the test suite in the sources, which exhaustively tries combinations. @node Obsolete @@-Commands @section Obsolete @@-Commands Here are Texinfo @@-commands which are obsolete or have been removed completely. This section is for historical purposes. @ftable @code @item @@refill This command used to refill and indent the paragraph after all the other processing has been done. It is no longer needed, since all formatters now automatically refill as needed, but you may still see it in the source to some manuals, as it does no harm. @cindex Contents, after title page @cindex Table of contents, after title page @item @@setcontentsaftertitlepage In the past, the contents commands were sometimes placed at the end of the file, after any indices and just before the @code{@@bye}, but we no longer recommend this. This command could be used by a user printing a manual, to force the contents to be printed after the title page (after the @samp{@@end titlepage} line) even if the @code{@@contents} command was at the end of the manual. @item @@setshortcontentsaftertitlepage This placed the short table of contents after the @samp{@@end titlepage} command even if the @code{@@shortcontents} command was at the end. @end ftable @node Tips @nodedescription Hints on how to write a Texinfo document. @appendix Tips and Hints Here are some tips for writing Texinfo documentation: @cindex Tips @cindex Usage tips @cindex Hints @itemize @bullet @item Write in the present tense, not in the past or the future. @item Write actively! For example, write ``We recommend that @dots{}'' rather than ``It is recommended that @dots{}''. @item Use 70 or 72 as your fill column. Longer lines are hard to read. @item Include a copyright notice and copying permissions. @item Design your manual so that it can be read sequentially, as far as possible. People tire of flipping back and forth to find information that should be presented to them as they need it. @end itemize @subsubheading Index, Index, Index! Write many index entries, in different ways. Readers like indices; they are helpful and convenient. Although it is easiest to write index entries as you write the body of the text, some people prefer to write entries afterwards. In either case, write an entry before the paragraph to which it applies. This way, an index entry points to the first page of a paragraph that is split across pages. Here are more index-related hints we have found valuable: @itemize @bullet @item Write each index entry differently, so each entry refers to a different place in the document. @item Write index entries only where a topic is discussed significantly. For example, it is not useful to index ``debugging information'' in a chapter on reporting bugs. Someone who wants to know about debugging information will certainly not find it in that chapter. @item Consistently capitalize the first word of every concept index entry, or else consistently use lowercase. Terse entries often call for lowercase; longer entries for capitalization. Whichever case convention you use, please use one or the other consistently! Mixing the two styles looks bad. @item Always capitalize or use uppercase for those words in an index for which this is proper, such as names of countries or acronyms. Always use the appropriate case for case-sensitive names, such as those in C or Lisp. @item Write the indexing commands that refer to a whole section immediately after the section command, and write the indexing commands that refer to a paragraph before that paragraph. In the example that follows, a blank line comes after the index entry for ``Leaping'': @example @group @@section The Dog and the Fox @@cindex Jumping, in general @@cindex Leaping @@cindex Dog, lazy, jumped over @@cindex Lazy dog jumped over @@cindex Fox, jumps over dog @@cindex Quick fox jumps over dog The quick brown fox jumps over the lazy dog. @end group @end example @noindent (Note that the example shows entries for the same concept that are written in different ways---@samp{Lazy dog}, and @samp{Dog, lazy}---so readers can look up the concept in different ways.) @end itemize @subsubheading Blank Lines @itemize @bullet @item Insert a blank line between a sectioning command and the first following sentence or paragraph, or between the indexing commands associated with the sectioning command and the first following sentence or paragraph, as shown in the tip on indexing. It makes the source easier to read. @item Always insert a blank line before a @code{@@table} command and after an @code{@@end table} command; but never insert a blank line after an @code{@@table} command. @need 1000 For example, @example @group Types of fox: @@table @@samp @@item Quick Jump over lazy dogs. @end group @group @@item Brown Also jump over lazy dogs. @@end table @end group @group @@noindent On the other hand, @dots{} @end group @end example Insert blank lines before and after @code{@@itemize} @dots{} @code{@@end itemize} and @code{@@enumerate} @dots{} @code{@@end enumerate} in the same way. @end itemize @subsubheading Complete Phrases Complete phrases are easier to read than @dots{} @itemize @bullet @item Write entries in an itemized list as complete sentences; or at least, as complete phrases. Incomplete expressions @dots{} awkward @dots{} like this. @item Write the prefatory sentence or phrase for a multi-item list or table as a complete expression. Do not write ``You can set:''; instead, write ``You can set these variables:''. The former expression sounds cut off. @end itemize @subsubheading Editions, Dates and Versions Include edition numbers, version numbers, and dates in the @code{@@copying} text (for people reading the Texinfo file, and for the legal copyright in the output files). Then use @code{@@insertcopying} in the @code{@@titlepage} section for people reading the printed output (@pxref{Short Sample}). It is easiest to handle such version information using @code{@@set} and @code{@@value}. @xref{@code{@@value} Example}, and @ref{GNU Sample Texts}. @subsubheading Definition Commands Definition commands are @code{@@deffn}, @code{@@defun}, @code{@@defmac}, and the like, and enable you to write descriptions in a uniform format. @itemize @bullet @item Write just one definition command for each entity you define with a definition command. The automatic indexing feature creates an index entry that leads the reader to the definition. @item Use @code{@@table} @dots{} @code{@@end table} in an appendix that contains a summary of functions, not @code{@@deffn} or other definition commands. @end itemize @subsubheading Capitalization @itemize @bullet @item Capitalize ``Texinfo''; it is a name. Do not write the @samp{x} or @samp{i} in uppercase. @item Capitalize ``Info''; it is a name. @item Write @TeX{} using the @code{@@TeX@{@}} command. Note the uppercase @samp{T} and @samp{X}. This command causes the formatters to typeset the name according to the wishes of Donald Knuth, who wrote @TeX{}. (Likewise @code{@@LaTeX@{@}} for @LaTeX{}.) @end itemize @subsubheading Spaces Do not use spaces to format a Texinfo file, except inside of @code{@@example} @dots{} @code{@@end example} and other literal environments and commands. @need 700 For example, @TeX{} fills the following: @example @group @@kbd@{C-x v@} @@kbd@{M-x vc-next-action@} Perform the next logical operation on the version-controlled file corresponding to the current buffer. @end group @end example @need 950 @noindent so it looks like this: @iftex @quotation @kbd{C-x v} @kbd{M-x vc-next-action} Perform the next logical operation on the version-controlled file corresponding to the current buffer. @end quotation @end iftex @ifnottex @quotation `C-x v' `M-x vc-next-action' Perform the next logical operation on the version-controlled file corresponding to the current buffer. @end quotation @end ifnottex @noindent In this case, the text should be formatted with @code{@@table}, @code{@@item}, and @code{@@itemx}, to create a table. @subsubheading @@code, @@samp, @@var, and @samp{---} @itemize @bullet @item Use @code{@@code} around Lisp symbols, including command names. For example, @example The main function is @@code@{vc-next-action@}, @dots{} @end example @item Avoid putting letters such as @samp{s} immediately after an @samp{@@code}. Such letters look bad. @item Use @code{@@var} around meta-variables. Do not write angle brackets around them. @item Use three hyphens in a row, @samp{---}, to indicate a long dash. The Info formatter reduces three hyphens to two; a long dash is typeset in other output formats. @end itemize @subsubheading Periods Outside of Quotes Place periods and other punctuation marks @emph{outside} of quotations, unless the punctuation is part of the quotation. This practice goes against some publishing conventions in the United States, but enables the reader to distinguish between the contents of the quotation and the whole passage. For example, you should write the following sentence with the period outside the end quotation marks: @example Evidently, @samp{au} is an abbreviation for ``author''. @end example @noindent since @samp{au} does @emph{not} serve as an abbreviation for @samp{author.} (with a period following the word). @subsubheading Introducing New Terms @itemize @bullet @item Introduce new terms so that a reader who does not know them can understand them from context; or write a definition for the term. For example, in the following, the terms ``check in'', ``register'' and ``delta'' are all appearing for the first time; the example sentence should be rewritten so they are understandable. @quotation The major function assists you in checking in a file to your version control system and registering successive sets of changes to it as deltas. @end quotation @item Use the @code{@@dfn} command around a word being introduced, to indicate that the reader should not expect to know the meaning already, and should expect to learn the meaning from this passage. @end itemize @subsubheading Program Invocation Nodes You can invoke programs such as Emacs, GCC, and @code{gawk} from a shell. The documentation for each program should contain a section that describes this. Unfortunately, if the node names and titles for these sections are all different, they are difficult for users to find. So, there is a convention to name such sections with a phrase beginning with the word `Invoking', as in `Invoking Emacs'; this way, users can find the section easily. @subsubheading ANSI C Syntax When you use @code{@@example} to describe a C function's calling conventions, use the ANSI C syntax, like this: @example void dld_init (char *@@var@{path@}); @end example @noindent And in the subsequent discussion, refer to the argument values by writing the same argument names, again highlighted with @code{@@var}. @need 800 Avoid the obsolete style that looks like this: @example #include <dld.h> dld_init (path) char *path; @end example Also, it is best to avoid writing @code{#include} above the declaration just to indicate that the function is declared in a header file. The practice may give the misimpression that the @code{#include} belongs near the declaration of the function. Either state explicitly which header file holds the declaration or, better yet, name the header file used for a group of functions at the beginning of the section that describes the functions. @anchor{texi-elements-by-size} @subsubheading Node Length Keep nodes (sections) to a reasonable length, whatever reasonable might be in the given context. Don't hesitate to break up long nodes into subnodes and have an extensive tree structure; that's what it's there for. Many times, readers will probably try to find a single specific point in the manual, using search, indexing, or just plain guessing, rather than reading the whole thing from beginning to end. You can use the @command{texi-elements-by-size} utility to see a list of all nodes (or sections) in the document, sorted by size (either lines or words), to find candidates for splitting. It's in the @file{util/} subdirectory of the Texinfo sources. @subsubheading Bad Examples Here are several examples of bad writing to avoid: In this example, say, `` @dots{} you must @code{@@dfn}@{check in@} the new version.'' That flows better. @quotation When you are done editing the file, you must perform a @code{@@dfn}@{check in@}. @end quotation In the following example, say, ``@dots{} makes a unified interface such as VC mode possible.'' @quotation SCCS, RCS and other version-control systems all perform similar functions in broadly similar ways (it is this resemblance which makes a unified control mode like this possible). @end quotation And in this example, you should specify what `it' refers to: @quotation If you are working with other people, it assists in coordinating everyone's changes so they do not step on each other. @end quotation @subsubheading And Finally @dots{} @itemize @bullet @item Pronounce @TeX{} as if the @samp{X} were a Greek `chi', as the last sound in the name `Bach'. But pronounce Texinfo as in `speck': ``teckinfo''. @item Write notes for yourself at the very end of a Texinfo file after the @code{@@bye}. None of the processors process text after the @code{@@bye}; it is as if the text were within @code{@@ignore} @dots{} @code{@@end ignore}. @end itemize @node Sample Texinfo Files @nodedescription Complete examples, including full texts. @appendix Sample Texinfo Files @cindex Sample Texinfo files This appendix includes texts to be used in GNU manuals. @node GNU Sample Texts @section GNU Sample Texts @cindex GNU sample texts @cindex Sample texts, GNU @cindex Full texts, GNU Following is a sample Texinfo document with the full texts that should be used (adapted as necessary) in GNU manuals. As well as the legal texts, it also serves as a practical example of how many elements in a GNU system can affect the manual. If you're not familiar with all these different elements, don't worry. They're not required and a perfectly good manual can be written without them. They're included here nonetheless because many manuals do (or could) benefit from them. @xref{Short Sample}, for a minimal example of a Texinfo file. Here are some notes on the example: @itemize @bullet @item @pindex automake@r{, and version info} @vindex UPDATED @r{Automake variable} @vindex UPDATED-MONTH @r{Automake variable} @vindex VERSION @r{Automake variable} @pindex time-stamp.el The @file{version.texi} in the @code{@@include} command is maintained automatically by Automake (@pxref{Texinfo,,, automake, GNU Automake}). It sets the @samp{VERSION}, @samp{UPDATED} and @samp{UPDATED-MONTH} values used elsewhere. If your distribution doesn't use Automake, but you do use Emacs, you may find the @code{time-stamp.el} package helpful (@pxref{Time Stamps,,, emacs, The GNU Emacs Manual}). @item The @code{@@syncodeindex} command reflects the recommendation to use only one index where possible, to make it easier for readers to look up index entries. @item The @code{@@dircategory} specify a category for the manual. It is used for constructing the Info directory. @xref{Directory Category}, which includes a variety of recommended category names. @xref{Installing Dir Entries}. @item The `Invoking' node is a GNU standard to help users find the basic information about command-line usage of a given program. @xref{Manual Structure Details,,, standards, GNU Coding Standards}. @item @cindex GNU Free Documentation License, including entire @cindex Free Documentation License, including entire This sample shows how to includes the FDL in a manual using the @command{@@include} command. The @file{fdl.texi} file is available in the Texinfo and other GNU source distributions. It is also available on the GNU website (at @uref{https://www.gnu.org/licenses/fdl-1.3.html}) along with guidance for using it. @item If the FSF is not the copyright holder, then use the appropriate name. @item For documents that express your personal views, feelings or experiences, it is more appropriate to use a license permitting only verbatim copying, rather than the FDL@. @xref{Verbatim Copying License}. @end itemize Here is the sample document: @verbatim \input texinfo @c -*-texinfo-*- @comment %**start of header @include version.texi @settitle GNU Sample @value{VERSION} @syncodeindex pg cp @comment %**end of header @copying This manual is for GNU Sample (version @value{VERSION}, @value{UPDATED}), which is an example in the Texinfo documentation. Copyright @copyright{} 2016 Free Software Foundation, Inc. @quotation Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with no Invariant Sections, with no Front-Cover Texts, and with no Back-Cover Texts. A copy of the license is included in the section entitled ``GNU Free Documentation License''. @end quotation @end copying @dircategory Texinfo documentation system @direntry * sample: (sample)Invoking sample. @end direntry @titlepage @title GNU Sample @subtitle for version @value{VERSION}, @value{UPDATED} @author A.U. Thor (@email{bug-sample@@gnu.org}) @page @vskip 0pt plus 1filll @insertcopying @end titlepage @contents @node Top @top GNU Sample This manual is for GNU Sample (version @value{VERSION}, @value{UPDATED}). @menu * Invoking sample:: * GNU Free Documentation License:: * Index:: @end menu @node Invoking sample @chapter Invoking sample @pindex sample @cindex invoking @command{sample} This is a sample manual. There is no sample program to invoke, but if there were, you could see its basic usage and command line options here. @node GNU Free Documentation License @appendix GNU Free Documentation License @include fdl.texi @node Index @unnumbered Index @printindex cp @bye @end verbatim @node Verbatim Copying License @section Verbatim Copying License @cindex Verbatim copying license @cindex License for verbatim copying For software manuals and other documentation, it is critical to use a license permitting free redistribution and updating, so that when a free program is changed, the documentation can be updated as well. On the other hand, for documents that express your personal views, feelings or experiences, it is more appropriate to use a license permitting only verbatim copying. Here is a sample text for such a license permitting verbatim copying only. This is just the license text itself. For a complete sample document, see the previous sections. @verbatim @copying This document is a sample for allowing verbatim copying only. Copyright @copyright{} 2016 Free Software Foundation, Inc. @quotation Permission is granted to make and distribute verbatim copies of this entire document without royalty provided the copyright notice and this permission notice are preserved. @end quotation @end copying @end verbatim @node All-permissive Copying License @section All-permissive Copying License @cindex All-permissive copying license @cindex License for all-permissive copying For software manuals and other documentation, it is important to use a license permitting free redistribution and updating, so that when a free program is changed, the documentation can be updated as well. On the other hand, for small supporting files, short manuals (under 300 lines long) and rough documentation (README files, INSTALL files, etc.), the full FDL would be overkill. They can use a simple all-permissive license. Here is a sample text for such an all-permissive license. This is just the license text itself. For a complete sample document, see the previous sections. @example Copyright @@copyright@{@} 2016 Free Software Foundation, Inc. Copying and distribution of this file, with or without modification, are permitted in any medium without royalty provided the copyright notice and this notice are preserved. @end example @node Texinfo Mode @nodedescription Using the GNU Emacs Texinfo mode. @appendix Using Texinfo Mode @cindex Texinfo mode @cindex Mode, using Texinfo @cindex GNU Emacs @cindex Emacs You may edit a Texinfo file with any text editor you choose. A Texinfo file is no different from any other ASCII file. However, GNU Emacs comes with a special mode, called Texinfo mode, that provides Emacs commands and tools to help ease your work. @node Texinfo Mode Overview @nodedescription How Texinfo mode can help you. @section Texinfo Mode Overview Texinfo mode provides special features for working with Texinfo files. You can: @itemize @bullet @item Insert frequently used @@-commands. @item Automatically create @code{@@node} lines. @item Show the structure of a Texinfo source file. @item Automatically create or update the `Next', `Previous', and `Up' pointers of a node. @item Automatically create or update menus. @item Automatically create a master menu. @item Format a part or all of a file for Info. @item Typeset and print part or all of a file. @end itemize Perhaps the two most helpful features are those for inserting frequently used @@-commands and for creating node pointers and menus. @node Emacs Editing @nodedescription Texinfo mode adds to GNU Emacs' general purpose editing features. @section The Usual GNU Emacs Editing Commands In most cases, the usual Text mode commands work the same in Texinfo mode as they do in Text mode. Texinfo mode adds new editing commands and tools to GNU Emacs' general purpose editing features. The major difference concerns filling. In Texinfo mode, the paragraph separation variable and syntax table are redefined so that Texinfo commands that should be on lines of their own are not inadvertently included in paragraphs. Thus, the @kbd{M-q} (@code{fill-paragraph}) command will refill a paragraph but not mix an indexing command on a line adjacent to it into the paragraph. In addition, Texinfo mode sets the @code{page-delimiter} variable to the value of @code{texinfo-chapter-level-regexp}; by default, this is a regular expression matching the commands for chapters and their equivalents, such as appendices. With this value for the page delimiter, you can jump from chapter title to chapter title with the @kbd{C-x ]} (@code{forward-page}) and @kbd{C-x [} (@code{backward-page}) commands and narrow to a chapter with the @kbd{C-x n p} (@code{narrow-to-page}) command. (@xref{Pages, , ,emacs, The GNU Emacs Manual}, for details about the page commands.) GNU Emacs automatically enters Texinfo mode when you visit a file with a @file{.texinfo}, @file{.texi} or @file{.txi} extension. Also, Emacs switches to Texinfo mode when you visit a file that has @samp{-*-texinfo-*-} in its first line. If ever you are in another mode and wish to switch to Texinfo mode, type @code{M-x texinfo-mode}. Like all other Emacs features, you can customize or enhance Texinfo mode as you wish. In particular, the keybindings are very easy to change. The keybindings described here are the default or standard ones. @node Inserting @nodedescription How to insert frequently used @@-commands. @section Inserting Frequently Used Commands @cindex Inserting frequently used commands @cindex Frequently used commands, inserting @cindex Commands, inserting them Texinfo mode provides commands to insert various frequently used @@-commands into the buffer. You can use these commands to save keystrokes. The insert commands are invoked by typing @kbd{C-c} twice and then the first letter of the @@-command: @table @kbd @findex texinfo-insert-@@code @item C-c C-c c @itemx M-x texinfo-insert-@@code Insert @code{@@code@{@}} and put the cursor between the braces. @findex texinfo-insert-@@dfn @item C-c C-c d @itemx M-x texinfo-insert-@@dfn Insert @code{@@dfn@{@}} and put the cursor between the braces. @findex texinfo-insert-@@end @item C-c C-c e @itemx M-x texinfo-insert-@@end Insert @code{@@end} and attempt to insert the correct following word, such as @samp{example} or @samp{table}. (This command does not handle nested lists correctly, but inserts the word appropriate to the immediately preceding list.) @findex texinfo-insert-@@item @item C-c C-c i @itemx M-x texinfo-insert-@@item Insert @code{@@item} and put the cursor at the beginning of the next line. @findex texinfo-insert-@@kbd @item C-c C-c k @itemx M-x texinfo-insert-@@kbd Insert @code{@@kbd@{@}} and put the cursor between the braces. @findex texinfo-insert-@@node @item C-c C-c n @itemx M-x texinfo-insert-@@node Insert @code{@@node} and a comment line listing the sequence for the `Next', `Previous', and `Up' nodes. Leave point after the @code{@@node}. @findex texinfo-insert-@@noindent @item C-c C-c o @itemx M-x texinfo-insert-@@noindent Insert @code{@@noindent} and put the cursor at the beginning of the next line. @findex texinfo-insert-dwim-@@ref @item C-c C-c r @itemx M-x texinfo-insert-dwim-@@ref This function and binding were added in Emacs 27.1. Inserts one of @code{@@pxref@{@}}, @code{@@xref@{@}}, or @code{@@ref@{@}} based on the text around point; calling it near an unclosed preceding open parenthesis results in @code{@@pxref@{@}}, at the beginning of a sentence or at @code{(point-min)} yields @code{@@xref@{@}}, any other location (including inside a word), will result in @code{@@ref@{@}}. A numeric argument says how many words the braces should surround. Puts the cursor between the braces. @findex texinfo-insert-@@samp @item C-c C-c s @itemx M-x texinfo-insert-@@samp Insert @code{@@samp@{@}} and put the cursor between the braces. @findex texinfo-insert-@@table @item C-c C-c t @itemx M-x texinfo-insert-@@table Insert @code{@@table} followed by a @key{SPC} and leave the cursor after the @key{SPC}. @findex texinfo-insert-@@var @item C-c C-c v @itemx M-x texinfo-insert-@@var Insert @code{@@var@{@}} and put the cursor between the braces. @findex texinfo-insert-@@example @item C-c C-c x @itemx M-x texinfo-insert-@@example Insert @code{@@example} and put the cursor at the beginning of the next line. @c M-@{ was the binding for texinfo-insert-braces; @c in Emacs 19, backward-paragraph will take this binding. @findex texinfo-insert-braces @item C-c C-c @{ @itemx M-x texinfo-insert-braces Insert @code{@{@}} and put the cursor between the braces. @findex up-list @item C-c @} @itemx C-c ] @itemx M-x up-list Move from between a pair of braces forward past the closing brace. Typing @kbd{C-c ]} is easier than typing @kbd{C-c @}}, which is, however, more mnemonic; hence the two keybindings. (Also, you can move out from between braces by typing @kbd{C-f}.) @end table To put a command such as @w{@code{@@code@{@dots{}@}}} around an @emph{existing} word, position the cursor in front of the word and type @kbd{C-u 1 C-c C-c c}. This makes it easy to edit existing plain text. The value of the prefix argument tells Emacs how many words following point to include between braces---@samp{1} for one word, @samp{2} for two words, and so on. Use a negative argument to enclose the previous word or words. If you do not specify a prefix argument, Emacs inserts the @@-command string and positions the cursor between the braces. This feature works only for those @@-commands that operate on a word or words within one line, such as @code{@@kbd} and @code{@@var}. This set of insert commands was created after analyzing the frequency with which different @@-commands are used in the @cite{GNU Emacs Manual} and the @cite{GDB Manual}. If you wish to add your own insert commands, you can bind a keyboard macro to a key, use abbreviations, or extend the code in @file{texinfo.el}. @findex texinfo-start-menu-description @cindex Menu description, start @cindex Description for menu, start @kbd{C-c C-c C-d} (@code{texinfo-start-menu-description}) is an insert command that works differently from the other insert commands. It inserts a node's section or chapter title in the space for the description in a menu entry line. (A menu entry has three parts, the entry name, the node name, and the description. Only the node name is required, but a description helps explain what the node is about. @xref{Menu Parts, , The Parts of a Menu}.) To use @code{texinfo-start-menu-description}, position point in a menu entry line and type @kbd{C-c C-c C-d}. The command looks for and copies the title that goes with the node name, and inserts the title as a description; it positions point at the beginning of the inserted text so you can edit it. The function does not insert the title if the menu entry line already contains a description. This command is only an aid to writing descriptions; it does not do the whole job. You must edit the inserted text since a title tends to use the same words as a node name but a useful description uses different words. @node Showing the Structure @nodedescription How to show the structure of a file. @section Showing the Sectioning Structure of a File @cindex Showing the sectioning structure of a file @cindex Sectioning structure of a file, showing @cindex Structure of a file, showing @cindex Outline of file structure, showing @cindex Contents-like outline of file structure @cindex File sectioning structure, showing @cindex Texinfo file sectioning structure, showing You can show the sectioning structure of a Texinfo file by using the @kbd{C-c C-s} command (@code{texinfo-show-structure}). This command lists the lines that begin with the @@-commands for @code{@@chapter}, @code{@@section}, and the like. It constructs what amounts to a table of contents. These lines are displayed in another buffer called the @samp{*Occur*} buffer. In that buffer, you can position the cursor over one of the lines and use the @kbd{C-c C-c} command (@code{occur-mode-goto-occurrence}), to jump to the corresponding spot in the Texinfo file. @table @kbd @findex texinfo-show-structure @item C-c C-s @itemx M-x texinfo-show-structure Show the @code{@@chapter}, @code{@@section}, and such lines of a Texinfo file. @findex occur-mode-goto-occurrence @item C-c C-c @itemx M-x occur-mode-goto-occurrence Go to the line in the Texinfo file corresponding to the line under the cursor in the @file{*Occur*} buffer. @end table If you call @code{texinfo-show-structure} with a prefix argument by typing @w{@kbd{C-u C-c C-s}}, it will list not only those lines with the @@-commands for @code{@@chapter}, @code{@@section}, and the like, but also the @code{@@node} lines. You can use @code{texinfo-show-structure} with a prefix argument to check whether the `Next', `Previous', and `Up' pointers of an @code{@@node} line are correct. Often, when you are working on a manual, you will be interested only in the structure of the current chapter. In this case, you can mark off the region of the buffer that you are interested in by using the @kbd{C-x n n} (@code{narrow-to-region}) command and @code{texinfo-show-structure} will work on only that region. To see the whole buffer again, use @w{@kbd{C-x n w}} (@code{widen}). (@xref{Narrowing, , , emacs, The GNU Emacs Manual}, for more information about the narrowing commands.) @vindex page-delimiter @cindex Page delimiter in Texinfo mode In addition to providing the @code{texinfo-show-structure} command, Texinfo mode sets the value of the page delimiter variable to match the chapter-level @@-commands. This enables you to use the @kbd{C-x ]} (@code{forward-page}) and @kbd{C-x [} (@code{backward-page}) commands to move forward and backward by chapter, and to use the @kbd{C-x n p} (@code{narrow-to-page}) command to narrow to a chapter. @xref{Pages, , , emacs, The GNU Emacs Manual}, for more information about the page commands. @node Using @code{texinfo-show-structure} @nodedescription How to use @code{texinfo-show-structure}. @subsection Using @code{texinfo-show-structure} @cindex Showing the structure of a file It is not always easy to keep track of the nodes, chapters, sections, and subsections of a Texinfo file. This is especially true if you are revising or adding to a Texinfo file that someone else has written. In GNU Emacs, in Texinfo mode, the @code{texinfo-show-structure} command lists all the lines that begin with the @@-commands that specify the structure: @code{@@chapter}, @code{@@section}, @code{@@appendix}, and so on. With an argument (@w{@kbd{C-u}} as prefix argument, if interactive), the command also shows the @code{@@node} lines. The @code{texinfo-show-structure} command is bound to @kbd{C-c C-s} in Texinfo mode, by default. The lines are displayed in a buffer called the @samp{*Occur*} buffer, indented by hierarchical level. For example, here is a part of what was produced by running @code{texinfo-show-structure} on this manual: @example @group Lines matching "^@@\\(chapter \\|sect\\|subs\\|subh\\| unnum\\|major\\|chapheading \\|heading \\|appendix\\)" in buffer texinfo.texi. @dots{} 4177:@@chapter Nodes 4198: @@heading Two Paths 4231: @@section Node and Menu Illustration 4337: @@section The @@code@{@@@@node@} Command 4393: @@subheading Choosing Node and Pointer Names 4417: @@subsection How to Write a @@code@{@@@@node@} Line 4469: @@subsection @@code@{@@@@node@} Line Tips @dots{} @end group @end example This says that lines 4337, 4393, and 4417 of @file{texinfo.texi} begin with the @code{@@section}, @code{@@subheading}, and @code{@@subsection} commands respectively. If you move your cursor into the @samp{*Occur*} window, you can position the cursor over one of the lines and use the @kbd{C-c C-c} command (@code{occur-mode-goto-occurrence}), to jump to the corresponding spot in the Texinfo file. @xref{Other Repeating Search, , Using Occur, emacs, The GNU Emacs Manual}, for more information about @code{occur-mode-goto-occurrence}. The first line in the @samp{*Occur*} window describes the @dfn{regular expression} specified by @var{texinfo-heading-pattern}. This regular expression is the pattern that @code{texinfo-show-structure} looks for. @xref{Regexps, , Using Regular Expressions, emacs, The GNU Emacs Manual}, for more information. When you invoke the @code{texinfo-show-structure} command, Emacs will display the structure of the whole buffer. If you want to see the structure of just a part of the buffer, of one chapter, for example, use the @kbd{C-x n n} (@code{narrow-to-region}) command to mark the region. (@xref{Narrowing, , , emacs, The GNU Emacs Manual}.) This is how the example used above was generated. (To see the whole buffer again, use @kbd{C-x n w} (@code{widen}).) If you call @code{texinfo-show-structure} with a prefix argument by typing @w{@kbd{C-u C-c C-s}}, it will list lines beginning with @code{@@node} as well as the lines beginning with the @@-sign commands for @code{@@chapter}, @code{@@section}, and the like. You can remind yourself of the structure of a Texinfo file by looking at the list in the @samp{*Occur*} window; and if you have mis-named a node or left out a section, you can correct the mistake. @node Using @code{occur} @nodedescription How to list all lines containing a pattern. @subsection Using @code{occur} @cindex Occurrences, listing with @code{@@occur} @findex occur Sometimes the @code{texinfo-show-structure} command produces too much information. Perhaps you want to remind yourself of the overall structure of a Texinfo file, and are overwhelmed by the detailed list produced by @code{texinfo-show-structure}. In this case, you can use the @code{occur} command directly. To do this, type: @example @kbd{M-x occur} @end example @noindent and then, when prompted, type a @dfn{regexp}, a regular expression for the pattern you want to match. (@xref{Regexps, , Regular Expressions, emacs, The GNU Emacs Manual}.) The @code{occur} command works from the current location of the cursor in the buffer to the end of the buffer. If you want to run @code{occur} on the whole buffer, place the cursor at the beginning of the buffer. For example, to see all the lines that contain the word @samp{@@chapter} in them, just type @samp{@@chapter}. This will produce a list of the chapters. It will also list all the sentences with @samp{@@chapter} in the middle of the line. If you want to see only those lines that start with the word @samp{@@chapter}, type @samp{^@@chapter} when prompted by @code{occur}. If you want to see all the lines that end with a word or phrase, end the last word with a @samp{$}; for example, @samp{catching mistakes$}. This can be helpful when you want to see all the nodes that are part of the same chapter or section and therefore have the same `Up' pointer. @xref{Other Repeating Search, , Using Occur, emacs , The GNU Emacs Manual}, for more information. @node Updating Nodes and Menus @nodedescription How to update or create new nodes and menus. @section Updating Nodes and Menus @cindex Updating nodes and menus @cindex Create nodes, menus automatically @cindex Insert nodes, menus automatically @cindex Automatically insert nodes, menus The @command{texi2any} command will create an Info file for a hierarchically organized Texinfo file that lacks `Next', `Previous' and `Up' pointers (@pxref{Writing a Node}). Thus, in general, there is no need for explicit `Next', `Previous', and `Up' pointers. In this setting, menus will be added automatically for nodes without an explicit menu. (@xref{Generic Translator @command{texi2any}}, for more information about @command{texi2any}.) If you still want explicit pointers, Texinfo mode provides commands for automatically creating or updating menus and node pointers. The commands are called ``update'' commands because their most frequent use is for updating a Texinfo file after you have worked on it; but you can use them to insert the `Next', `Previous', and `Up' pointers into an @code{@@node} line that has none and to create menus in a file that has none. @node Updating Commands @nodedescription Five major updating commands. @subsection The Updating Commands You can use the updating commands to: @itemize @bullet @item insert or update the `Next', `Previous', and `Up' pointers of a node, @item insert or update the menu for a section, and @item create a master menu for a Texinfo source file. @end itemize You can also use the commands to update all the nodes and menus in a region or in a whole Texinfo file. The updating commands work only with conventional Texinfo files, which are structured hierarchically like books. In such files, a structuring command line must follow closely after each @code{@@node} line, except for the `Top' @code{@@node} line. (A @dfn{structuring command line} is a line beginning with @code{@@chapter}, @code{@@section}, or other similar command.) You can write the structuring command line on the line that follows immediately after an @code{@@node} line or else on the line that follows after a single @code{@@comment} line or a single @code{@@ifinfo} line. You cannot interpose more than one line between the @code{@@node} line and the structuring command line; and you may interpose only a @code{@@comment} line or an @code{@@ifinfo} line. Commands which work on a whole buffer require that the `Top' node be followed by a node with a @code{@@chapter} or equivalent-level command. The menu updating commands will not create a main or master menu for a Texinfo file that has only @code{@@chapter}-level nodes! The menu updating commands only create menus @emph{within} nodes for lower level nodes. To create a menu of chapters, you must provide a `Top' node. The menu updating commands remove menu entries that refer to other Info files since they do not refer to nodes within the current buffer. This is a deficiency. Rather than use menu entries, you can use cross references to refer to other Info files. None of the updating commands affect cross-references. Texinfo mode has five updating commands that are used most often: two are for updating the node pointers or menu of a single node (or a region); two are for updating every node pointer and menu in a file; and one, the @code{texinfo-master-menu} command, is for creating a master menu for a complete file, and optionally, for updating every node and menu in the whole Texinfo file. The @code{texinfo-master-menu} command is the primary command: @table @kbd @findex texinfo-master-menu @item C-c C-u m @itemx M-x texinfo-master-menu Create or update a master menu that includes all the other menus (incorporating the descriptions from pre-existing menus, if any). With an argument (prefix argument, @kbd{C-u,} if interactive), first create or update all the nodes and all the regular menus in the buffer before constructing the master menu. (@xref{The Top Node, , The Top Node and Master Menu}, for more about a master menu.) For @code{texinfo-master-menu} to work, the Texinfo file must have a `Top' node and at least one subsequent node. After extensively editing a Texinfo file, you can type the following: @example C-u M-x texinfo-master-menu @exdent or C-u C-c C-u m @end example @noindent This updates all the nodes and menus completely and all at once. @end table The other major updating commands do smaller jobs and are designed for the person who updates nodes and menus as he or she writes a Texinfo file. @need 1000 The commands are: @table @kbd @findex texinfo-update-node @item C-c C-u C-n @itemx M-x texinfo-update-node Insert the `Next', `Previous', and `Up' pointers for the node that point is within (i.e., for the @code{@@node} line preceding point). If the @code{@@node} line has pre-existing `Next', `Previous', or `Up' pointers in it, the old pointers are removed and new ones inserted. With an argument (prefix argument, @kbd{C-u}, if interactive), this command updates all @code{@@node} lines in the region (which is the text between point and mark). @findex texinfo-make-menu @item C-c C-u C-m @itemx M-x texinfo-make-menu Create or update the menu in the node that point is within. With an argument (@kbd{C-u} as prefix argument, if interactive), the command makes or updates menus for the nodes which are either within or a part of the region. Whenever @code{texinfo-make-menu} updates an existing menu, the descriptions from that menu are incorporated into the new menu. This is done by copying descriptions from the existing menu to the entries in the new menu that have the same node names. If the node names are different, the descriptions are not copied to the new menu. @findex texinfo-every-node-update @item C-c C-u C-e @itemx M-x texinfo-every-node-update Insert or update the `Next', `Previous', and `Up' pointers for every node in the buffer. @findex texinfo-all-menus-update @item C-c C-u C-a @itemx M-x texinfo-all-menus-update Create or update all the menus in the buffer. With an argument (@kbd{C-u} as prefix argument, if interactive), first insert or update all the node pointers before working on the menus. If a master menu exists, the @code{texinfo-all-menus-update} command updates it; but the command does not create a new master menu if none already exists. (Use the @code{texinfo-master-menu} command for that.) When working on a document that does not merit a master menu, you can type the following: @example C-u C-c C-u C-a @exdent or C-u M-x texinfo-all-menus-update @end example @noindent This updates all the nodes and menus. @end table The @code{texinfo-column-for-description} variable specifies the column to which menu descriptions are indented. By default, the value is 32 although it can be useful to reduce it to as low as 24. You can set the variable via customization (@pxref{Customization,,, emacs, The GNU Emacs Manual}) or with the @kbd{M-x set-variable} command (@pxref{Examining, , Examining and Setting Variables, emacs, The GNU Emacs Manual}). Also, the @code{texinfo-indent-menu-description} command may be used to indent existing menu descriptions to a specified column. Finally, if you wish, you can use the @code{texinfo-insert-node-lines} command to insert missing @code{@@node} lines into a file. In particular, you can ignore @code{@@node} lines altogether in your first draft and then use the @code{texinfo-insert-node-lines} command to create @code{@@node} lines for you. However, we do not recommend this practice. It is better to name the node itself at the same time that you write a segment so you can easily make cross-references. Useful cross-references are an especially important feature of a good Texinfo manual. (@xref{Other Updating Commands}, for more information.) @node Updating Requirements @nodedescriptionblock How to structure a Texinfo file for using the updating command. @end nodedescriptionblock @subsection Updating Requirements @cindex Updating requirements @cindex Requirements for updating commands To use the updating commands, you must organize the Texinfo file hierarchically with chapters, sections, subsections, and the like. When you construct the hierarchy of the manual, do not `jump down' more than one level at a time: you can follow the `Top' node with a chapter, but not with a section; you can follow a chapter with a section, but not with a subsection. However, you may `jump up' any number of levels at one time---for example, from a subsection to a chapter. Each @code{@@node} line, with the exception of the line for the `Top' node, must be followed by a line with a structuring command such as @code{@@chapter}, @code{@@section}, or @code{@@unnumberedsubsec}. Each @code{@@node} line/structuring-command line combination must look either like this: @example @group @@node Comments, Minimum, Conventions, Overview @@comment node-name, next, previous, up @@section Comments @end group @end example or like this (without the @code{@@comment} line): @example @group @@node Comments, Minimum, Conventions, Overview @@section Comments @end group @end example or like this (without the explicit node pointers): @example @group @@node Comments @@section Comments @end group @end example @noindent In this example, `Comments' is the name of both the node and the section. The next node is called `Minimum' and the previous node is called `Conventions'. The `Comments' section is within the `Overview' node, which is specified by the `Up' pointer. If a file has a `Top' node, it must be called @samp{top} or @samp{Top} and be the first node in the file. The menu updating commands create a menu of sections within a chapter, a menu of subsections within a section, and so on. This means that you must have a `Top' node if you want a menu of chapters. @node Update Multiple Files @nodedescriptionblock How to create and update nodes and menus when using included files. @end nodedescriptionblock @subsection Update Outer File and Include Files @anchor{@code{texinfo-multiple-files-update}}@c old node name @findex texinfo-multiple-files-update GNU Emacs Texinfo mode provides the @code{texinfo-multiple-files-update} command. This command creates or updates `Next', `Previous', and `Up' pointers of included files as well as those in the outer or overall Texinfo file, and it creates or updates a main menu in the outer file. Depending on whether you call it with optional arguments, the command updates only the pointers in the first @code{@@node} line of the included files or all of them. With @kbd{C-u} as a prefix argument, create and insert a master menu in the outer file. With a numeric prefix argument, such as @kbd{C-u 2}, first update all the menus and all the `Next', `Previous', and `Up' pointers of all the included files before creating and inserting a master menu in the outer file. In more details: @table @kbd @item M-x texinfo-multiple-files-update Called without any arguments: @itemize @minus @item Create or update the `Next', `Previous', and `Up' pointers of the first @code{@@node} line in each file included in an outer or overall Texinfo file. @item Create or update the `Top' level node pointers of the outer or overall file. @item Create or update a main menu in the outer file. @end itemize @item C-u M-x texinfo-multiple-files-update Called with @kbd{C-u} as a prefix argument: @itemize @minus{} @item Create or update pointers in the first @code{@@node} line in each included file. @item Create or update the `Top' level node pointers of the outer file. @item Create and insert a master menu in the outer file. The master menu is made from all the menus in all the included files. @end itemize @item C-u 8 M-x texinfo-multiple-files-update Called with a numeric prefix argument, such as @kbd{C-u 8}: @itemize @minus @item Create or update @emph{all} the `Next', `Previous', and `Up' pointers of all the included files. @item Create or update @emph{all} the menus of all the included files. @item Create or update the `Top' level node pointers of the outer or overall file. @item And then create a master menu in the outer file. This is similar to invoking @code{texinfo-master-menu} with an argument when you are working with just one file. @end itemize @end table Note the use of the prefix argument in interactive use: with a regular prefix argument, just @w{@kbd{C-u}}, the @code{texinfo-multiple-files-update} command inserts a master menu; with a numeric prefix argument, such as @kbd{C-u 8}, the command updates @emph{every} pointer and menu in @emph{all} the files and then inserts a master menu. @node Include Files Requirements @nodedescriptionblock How to structure outer file and include files for the updating command. @end nodedescriptionblock @subsection Include Files Requirements @cindex Include files requirements @cindex Requirements for include files If you plan to use the @code{texinfo-multiple-files-update} command, the outer Texinfo file that lists included files within it should contain nothing but the beginning and end parts of a Texinfo file, and a number of @code{@@include} commands listing the included files. It should not even include indices, which should be listed in an included file of their own. Moreover, each of the included files must contain exactly one highest level node (conventionally, @code{@@chapter} or equivalent), and this node must be the first node in the included file. Furthermore, each of these highest level nodes in each included file must be at the same hierarchical level in the file structure. Usually, each is a @code{@@chapter}, an @code{@@appendix}, or an @code{@@unnumbered} node. Thus, normally, each included file contains one, and only one, chapter or equivalent-level node. The outer file should contain only @emph{one} node, the `Top' node. It should @emph{not} contain any nodes besides the single `Top' node. The @code{texinfo-multiple-files-update} command will not process them. @node Other Updating Commands @nodedescriptionblock How to indent descriptions, insert missing nodes lines, and update nodes in sequence. @end nodedescriptionblock @subsection Other Updating Commands In addition to the major updating commands, Texinfo mode possesses several less frequently used updating commands: @table @kbd @findex texinfo-insert-node-lines @item M-x texinfo-insert-node-lines Insert @code{@@node} lines before the @code{@@chapter}, @code{@@section}, and other sectioning commands wherever they are missing throughout a region in a Texinfo file. With an argument (@kbd{C-u} as prefix argument, if interactive), the command @code{texinfo-insert-node-lines} not only inserts @code{@@node} lines but also inserts the chapter or section titles as the names of the corresponding nodes. In addition, it inserts the titles as node names in pre-existing @code{@@node} lines that lack names. Since node names should be more concise than section or chapter titles, you must manually edit node names so inserted. For example, the following marks a whole buffer as a region and inserts @code{@@node} lines and titles throughout: @example C-x h C-u M-x texinfo-insert-node-lines @end example This command inserts titles as node names in @code{@@node} lines; the @code{texinfo-start-menu-description} command (@pxref{Inserting, Inserting Frequently Used Commands}) inserts titles as descriptions in menu entries, a different action. However, in both cases, you need to edit the inserted text. @findex texinfo-indent-menu-description @item M-x texinfo-indent-menu-description Indent every description in the menu following point to the specified column. You can use this command to give yourself more space for descriptions. With an argument (@kbd{C-u} as prefix argument, if interactive), the @code{texinfo-indent-menu-description} command indents every description in every menu in the region. However, this command does not indent the second and subsequent lines of a multi-line description. @findex texinfo-sequential-node-update @item M-x texinfo-sequential-node-update Insert the names of the nodes immediately following and preceding the current node as the `Next' or `Previous' pointers regardless of those nodes' hierarchical level. This means that the `Next' node of a subsection may well be the next chapter. Sequentially ordered nodes are useful for novels and other documents that you read through sequentially. (However, in Info, the @kbd{g *} command lets you look through the file sequentially, so sequentially ordered nodes are not strictly necessary.) With an argument (prefix argument, if interactive), the @code{texinfo-sequential-node-update} command sequentially updates all the nodes in the region. @end table @node Info Formatting @nodedescription How to format for Info. @section Formatting for Info @cindex Formatting for Info @cindex Running an Info formatter @cindex Info formatting Texinfo mode provides several commands for formatting part or all of a Texinfo file for Info. @node @command{texi2any} in Emacs @nodedescription How to run @command{texi2any} from Emacs. @subsection Running @command{texi2any}/@command{makeinfo} Within Emacs @c anchor{makeinfo in Emacs}@c prev name @anchor{@code{makeinfo} in Emacs}@c prev name @anchor{@command{makeinfo} Advantages}@c node merged in this one @cindex Running @command{makeinfo} in Emacs @cindex Running @command{texi2any} in Emacs @cindex @command{makeinfo} inside Emacs @cindex @command{texi2any} inside Emacs @cindex Shell, running @command{makeinfo} in @cindex Shell, running @command{texi2any} in The @command{texi2any} program provides better error messages than either of the Emacs formatting commands. We recommend it. The @command{texi2any} program is independent of Emacs. You can run @command{texi2any} (or @command{makeinfo}) in GNU Emacs Texinfo mode by using either the @code{makeinfo-region} or the @code{makeinfo-buffer} commands. In Texinfo mode, the commands are bound to @kbd{C-c C-m C-r} and @kbd{C-c C-m C-b} by default. @table @kbd @item C-c C-m C-r @itemx M-x makeinfo-region Format the current region for Info. @findex makeinfo-region @item C-c C-m C-b @itemx M-x makeinfo-buffer Format the current buffer for Info. @findex makeinfo-buffer @end table When you invoke @code{makeinfo-region} the output goes to a temporary @c FIXME or to the file based on input file name? buffer. When you invoke @code{makeinfo-buffer} output goes to the file set with @code{@@setfilename} (@pxref{@code{@@setfilename}}). The Emacs @code{makeinfo-region} and @code{makeinfo-buffer} commands run the @command{texi2any} program in a temporary shell buffer. If @command{texi2any} finds any errors, Emacs displays the error messages in the temporary buffer. @cindex Errors, parsing @cindex Parsing errors @findex next-error You can parse the error messages by typing @kbd{C-x `} (@code{next-error}). This causes Emacs to go to and position the cursor on the line in the Texinfo source that @command{texi2any} thinks caused the error. @xref{Compilation, , Running @code{make} or Compilers Generally, emacs, The GNU Emacs Manual}, for more information about using the @code{next-error} command. In addition, you can kill the shell in which the @command{texi2any} command is running or make the shell buffer display its most recent output. @table @kbd @findex makeinfo-kill-job @item C-c C-m C-k @itemx M-x makeinfo-kill-job Kill the current running @command{texi2any} (or @command{makeinfo}) job (from @code{makeinfo-region} or @code{makeinfo-buffer}). @findex makeinfo-recenter-output-buffer @item C-c C-m C-l @itemx M-x makeinfo-recenter-output-buffer Redisplay the @command{texi2any} shell buffer to display its most recent output. @end table @noindent (Note that the parallel commands for killing and recentering a @TeX{} job are @kbd{C-c C-t C-k} and @kbd{C-c C-t C-l}. @xref{Texinfo Mode Printing}.) You can specify options for @command{texi2any} by setting the @code{makeinfo-options} variable with either the @kbd{M-x customize} or the @kbd{M-x set-variable} command, or by setting the variable in your @file{.emacs} initialization file. For example, you could write the following in your @file{.emacs} file: @example @group (setq makeinfo-options "--paragraph-indent=0 --no-split --fill-column=70 --verbose") @end group @end example @noindent @c Writing these three cross-references using xref results in @c three references to the same named manual, which looks strange. @iftex For more information, see @ref{@command{texi2any} Options}, as well as ``Easy Customization Interface,'' ``Examining and Setting Variables,'' and ``Init File'' in @cite{The GNU Emacs Manual}. @end iftex @ifnottex For more information, see@* @ref{Easy Customization, , Easy Customization Interface, emacs, The GNU Emacs Manual},@* @ref{Examining, , Examining and Setting Variables, emacs, The GNU Emacs Manual},@* @ref{Init File, , , emacs, The GNU Emacs Manual}, and@* @ref{@command{texi2any} Options}. @end ifnottex @node @code{texinfo-format} commands @nodedescriptionblock Two Info formatting commands written in Emacs Lisp are an alternative to @command{texi2any}. @end nodedescriptionblock @subsection The @code{texinfo-format@dots{}} Commands @c anchor{texinfo-format commands}@c prev name In GNU Emacs in Texinfo mode, you can format part or all of a Texinfo file with the @code{texinfo-format-region} command. This formats the current region and displays the formatted text in a temporary buffer called @samp{*Info Region*}. Similarly, you can format a buffer with the @code{texinfo-format-buffer} command. This command creates a new buffer and generates the Info file in it. Typing @kbd{C-x C-s} will save the Info file under the name specified by the @code{@@setfilename} line which must be near the beginning of the Texinfo file. @table @kbd @findex texinfo-format-region @item C-c C-e C-r @itemx @code{texinfo-format-region} Format the current region for Info. @findex texinfo-format-buffer @item C-c C-e C-b @itemx @code{texinfo-format-buffer} Format the current buffer for Info. @end table The @code{texinfo-format-region} and @code{texinfo-format-buffer} commands provide you with some error checking, and other functions can provide you with further help in finding formatting errors. These procedures are described in an appendix; see @ref{Catching Mistakes}. However, the @command{texi2any} program provides better error checking (@pxref{@command{texi2any} in Emacs}). A peculiarity of the @code{texinfo-format-buffer} and @code{texinfo-format-region} commands is that they do not indent (nor fill) paragraphs that contain @code{@@w} or @code{@@*} commands. @node Printing with Emacs @nodedescription How to format with @TeX{} and print with Emacs. @section Formatting and Printing with Emacs GNU Emacs can be used for formatting and printing with @TeX{}, from an Emacs Shell. Texinfo mode also provides predefined key commands for formatting and printing. @node Texinfo Mode Printing @nodedescription How to format and print part or all of a file. @subsection Formatting and Printing in Texinfo Mode @cindex Region printing in Texinfo mode @cindex Format and print in Texinfo mode @cindex Print and format in Texinfo mode Texinfo mode provides several predefined key commands for @TeX{} formatting and printing. These include commands for sorting indices, looking at the printer queue, killing the formatting job, and recentering the display of the buffer in which the operations occur. @cindex Printing a region or buffer @cindex Region formatting and printing @cindex Buffer formatting and printing @cindex Part of file formatting and printing Often, when you are writing a document, you want to typeset and print only part of a file to see what it will look like. You can use the @code{texinfo-tex-region} and related commands for this purpose. Use the @code{texinfo-tex-buffer} command to format all of a buffer. For @code{texinfo-tex-region} or @code{texinfo-tex-buffer} to work, the file @emph{must} start with a @samp{\input texinfo} line and must include a @code{@@settitle} line. The file must end with @code{@@bye} on a line by itself. (When you use @code{texinfo-tex-region}, you must surround the @code{@@settitle} line with start-of-header and end-of-header lines.) @table @kbd @findex texinfo-tex-buffer @item C-c C-t C-b @itemx M-x texinfo-tex-buffer Run @command{texi2dvi} on the buffer. In addition to running @TeX{} on the buffer, this command automatically creates or updates indices as needed. @item C-c C-t C-r @itemx M-x texinfo-tex-region Run @TeX{} on the current region. If @@-commands related to printed output are between the start-of-header and end-of-header lines, then @code{texinfo-tex-region} will format the region accordingly. For example, if you write the @code{@@smallbook} command between the start-of-header and end-of-header lines, @code{texinfo-tex-region}, will format the region in ``small'' book size. @item C-c C-t C-i @itemx M-x texinfo-texindex Run @command{texindex} to sort the indices of a Texinfo file formatted with @code{texinfo-tex-region}. The @code{texinfo-tex-region} command does not run @command{texindex} automatically; it only runs the @command{tex} typesetting command. You must run the @code{texinfo-tex-region} command a second time after sorting the raw index files with the @command{texindex} command. (Usually, you do not format an index when you format a region, only when you format a buffer. Now that the @command{texi2dvi} command exists, there is little or no need for this command.) @item C-c C-t C-p @itemx M-x texinfo-tex-print Print a DVI file that was made with @code{texinfo-tex-region} or @code{texinfo-tex-buffer}. @item C-c C-t C-q @itemx M-x tex-show-print-queue Show the print queue. @item C-c C-t C-d @itemx M-x texinfo-delete-from-print-queue Delete a job from the print queue; you will be prompted for the job number shown by a preceding @kbd{C-c C-t C-q} command (@code{texinfo-show-tex-print-queue}). @item C-c C-t C-k @itemx M-x tex-kill-job Kill the currently running @TeX{} job started by either @code{texinfo-tex-region} or @code{texinfo-tex-buffer}, or any other process running in the Texinfo shell buffer. @item C-c C-t C-x @itemx M-x texinfo-quit-job Quit a @TeX{} formatting job that has stopped because of an error by sending an @key{x} to it. When you do this, @TeX{} preserves a record of what it did in a @file{.log} file. @item C-c C-t C-l @itemx M-x tex-recenter-output-buffer Redisplay the shell buffer in which the @TeX{} printing and formatting commands are run to show its most recent output. @end table @need 1000 Thus, the usual sequence of commands for formatting a buffer is as follows (with comments to the right): @example @group C-c C-t C-b @r{Run @command{texi2dvi} on the buffer.} C-c C-t C-p @r{Print the DVI file.} C-c C-t C-q @r{Display the printer queue.} @end group @end example The Texinfo mode @TeX{} formatting commands start a subshell in Emacs called the @file{*tex-shell*}. The @code{texinfo-tex-command}, @code{texinfo-texindex-command}, and @code{tex-dvi-print-command} commands are all run in this shell. You can watch the commands operate in the @samp{*tex-shell*} buffer, and you can switch to and from and use the @samp{*tex-shell*} buffer as you would any other shell buffer. @need 1500 The formatting and print commands depend on the values of several variables. The default values are: @example @group @r{Variable} @r{Default value} texinfo-texi2dvi-command "texi2dvi" texinfo-tex-command "tex" texinfo-texindex-command "texindex" texinfo-delete-from-print-queue-command "lprm" texinfo-tex-trailer "@@bye" tex-start-of-header "%**start" tex-end-of-header "%**end" tex-dvi-print-command "lpr -d" tex-show-queue-command "lpq" @end group @end example You can change the values of these variables with the @kbd{M-x set-variable} command (@pxref{Examining, , Examining and Setting Variables, emacs, The GNU Emacs Manual}), or with your @file{.emacs} initialization file (@pxref{Init File, , , emacs, The GNU Emacs Manual}). @cindex Customize Emacs package (@t{Development/Docs/Texinfo}) Beginning with version 20, GNU Emacs offers a user-friendly interface, called @dfn{Customize}, for changing values of user-definable variables. @xref{Easy Customization, , Easy Customization Interface, emacs, The GNU Emacs Manual}, for more details about this. The Texinfo variables can be found in the @samp{Development/Docs/Texinfo} group, once you invoke the @kbd{M-x customize} command. @node Compile-Command @nodedescription How to print using Emacs's compile command. @subsection Using the Local Variables List @cindex Local variables @cindex Compile command for formatting @cindex Format with the compile command Yet another way to apply the @TeX{} formatting command to a Texinfo file is to put that command in a @dfn{local variables list} at the end of the Texinfo file. You can then specify the @command{tex} or @command{texi2dvi} commands as a @code{compile-command} and have Emacs run it by typing @kbd{M-x compile}. This creates a special shell called the @file{*compilation*} buffer in which Emacs runs the compile command. For example, at the end of the @file{gdb.texi} file, after the @code{@@bye}, you could put the following: @example @group Local Variables: compile-command: "texi2dvi gdb.texi" End: @end group @end example @noindent This technique is most often used by programmers who also compile programs this way; see @ref{Compilation, , , emacs, The GNU Emacs Manual}. @node Texinfo Mode Summary @nodedescription Summary of all the Texinfo mode commands. @section Texinfo Mode Summary In Texinfo mode, each set of commands has default keybindings that begin with the same keys. All the commands that are custom-created for Texinfo mode begin with @kbd{C-c}. The keys are somewhat mnemonic. @subheading Insert Commands The insert commands are invoked by typing @kbd{C-c} twice and then the first letter of the @@-command to be inserted. (It might make more sense mnemonically to use @kbd{C-c C-i}, for `custom insert', but @kbd{C-c C-c} is quick to type.) @example C-c C-c c @r{Insert} @samp{@@code}. C-c C-c d @r{Insert} @samp{@@dfn}. C-c C-c e @r{Insert} @samp{@@end}. C-c C-c i @r{Insert} @samp{@@item}. C-c C-c n @r{Insert} @samp{@@node}. C-c C-c s @r{Insert} @samp{@@samp}. C-c C-c v @r{Insert} @samp{@@var}. C-c @{ @r{Insert braces.} C-c ] C-c @} @r{Move out of enclosing braces.} @group C-c C-c C-d @r{Insert a node's section title} @r{in the space for the description} @r{in a menu entry line.} @end group @end example @subheading Show Structure The @code{texinfo-show-structure} command is often used within a narrowed region. @example C-c C-s @r{List all the headings.} @end example @subheading The Master Update Command The @code{texinfo-master-menu} command creates a master menu; and can be used to update every node and menu in a file as well. @c Probably should use @tables in this section. @example @group C-c C-u m M-x texinfo-master-menu @r{Create or update a master menu.} @end group @group C-u C-c C-u m @r{With @kbd{C-u} as a prefix argument, first} @r{create or update all nodes and regular} @r{menus, and then create a master menu.} @end group @end example @subheading Update Pointers The update pointer commands are invoked by typing @kbd{C-c C-u} and then either @kbd{C-n} for @code{texinfo-update-node} or @kbd{C-e} for @code{texinfo-every-node-update}. @example C-c C-u C-n @r{Update a node.} C-c C-u C-e @r{Update every node in the buffer.} @end example @subheading Update Menus Invoke the update menu commands by typing @kbd{C-c C-u} and then either @kbd{C-m} for @code{texinfo-make-menu} or @kbd{C-a} for @code{texinfo-all-menus-update}. To update both nodes and menus at the same time, precede @kbd{C-c C-u C-a} with @kbd{C-u}. @example C-c C-u C-m @r{Make or update a menu.} @group C-c C-u C-a @r{Make or update all} @r{menus in a buffer.} @end group @group C-u C-c C-u C-a @r{With @kbd{C-u} as a prefix argument,} @r{first create or update all nodes and} @r{then create or update all menus.} @end group @end example @subheading Format for Info The Info formatting commands that are written in Emacs Lisp are invoked by typing @kbd{C-c C-e} and then either @kbd{C-r} for a region or @kbd{C-b} for the whole buffer. The Info formatting commands that are based on the @command{texi2any}/@command{makeinfo} program are invoked by typing @kbd{C-c C-m} and then either @kbd{C-r} for a region or @kbd{C-b} for the whole buffer. @need 800 @noindent Use the @code{texinfo-format@dots{}} commands: @example @group C-c C-e C-r @r{Format the region.} C-c C-e C-b @r{Format the buffer.} @end group @end example @need 750 @noindent Use @command{texi2any}/@command{makeinfo}: @example C-c C-m C-r @r{Format the region.} C-c C-m C-b @r{Format the buffer.} C-c C-m C-l @r{Recenter the @command{texi2any} output buffer.} C-c C-m C-k @r{Kill the @command{texi2any} formatting job.} @end example @subheading Typeset and Print The @TeX{} typesetting and printing commands are invoked by typing @kbd{C-c C-t} and then another control command: @kbd{C-r} for @code{texinfo-tex-region}, @kbd{C-b} for @code{texinfo-tex-buffer}, and so on. @example C-c C-t C-r @r{Run @TeX{} on the region.} C-c C-t C-b @r{Run} @command{texi2dvi} @r{on the buffer.} C-c C-t C-i @r{Run} @command{texindex}. C-c C-t C-p @r{Print the DVI file.} C-c C-t C-q @r{Show the print queue.} C-c C-t C-d @r{Delete a job from the print queue.} C-c C-t C-k @r{Kill the current @TeX{} formatting job.} C-c C-t C-x @r{Quit a currently stopped @TeX{} formatting job.} C-c C-t C-l @r{Recenter the output buffer.} @end example @subheading Other Updating Commands The remaining updating commands do not have standard keybindings because they are rarely used. @example @group M-x texinfo-insert-node-lines @r{Insert missing @code{@@node} lines in region.} @r{With @kbd{C-u} as a prefix argument,} @r{use section titles as node names.} @end group @group M-x texinfo-multiple-files-update @r{Update a multi-file document.} @r{With @kbd{C-u 2} as a prefix argument,} @r{create or update all nodes and menus} @r{in all included files first.} @end group @group M-x texinfo-indent-menu-description @r{Indent descriptions.} @end group @group M-x texinfo-sequential-node-update @r{Insert node pointers in strict sequence.} @end group @end example @node Formatting Info files @nodedescription Processing directly Info files. @section Direct Formatting of Info files @cindex Direct formatting of Info files In general, there is no need to edit or process Info files. Most of the content of Info file is plain text, but the tag tables require computing offsets for nodes and indirect files (@pxref{Tag and Split Files}), which is impractical. The Texinfo processors output well-formatted Info from Texinfo input. Also, lot of information from the Texinfo source is lost in the Info file. The Texinfo source is therefore more suitable to analyse a manual, be it for error reporting, for statistics, or to set up translations. Still, especially with manually written Info files, there are some situations where it may be interesting to process Info files directly, in particular to compute Info files node offsets and to compute split Info files file offsets. Two Emacs commands do that. @code{Info-tagify} adds a tag table for a nonsplit file lacking one. This function is also useful for Info file validation (@pxref{Running @code{Info-validate}}). It is also possible to split a nonsplit Info file with @code{Info-split}. @node Tagifying @nodedescription How to tagify a file. @subsection Tagifying a File @cindex Making a tag table manually @cindex Tag table, making manually @cindex Info files @subentry making a tag table Texinfo processors create tag tables automatically. The only exception arise when @code{texinfo-format-buffer} is called with a prefix, as @kbd{C-u M-x texinfo-format-buffer}, to create an non split Info file without a tag table (which can be useful in some cases for Info file validation, @pxref{Unsplit and Tagify}). Adding a tag table is therefore more generally useful for manually written Info files. To create a tag table for an nonsplit file, visit the Info file you wish to tagify and type: @example M-x Info-tagify @end example @noindent (Note the uppercase @samp{I} in @code{Info-tagify}.) This creates an Info file with a tag table. A tag table is part of a well formed Info file (@pxref{Tag and Split Files}). A tag table is also needed to validate or split the Info file. @node Splitting @nodedescription How to split a file manually. @subsection Splitting a File Manually @cindex Splitting an Info file manually @cindex Info files @subentry splitting manually You should split a large file or else let the @code{texinfo-format-buffer} or @code{makeinfo-buffer} command do it for you automatically. (Generally you will let one of the formatting commands do this job for you. @xref{Info Formatting}.) The split-off files are called the indirect subfiles. Tag tables are created automatically by the formatting command; you only need to create a tag table yourself if you are doing the job manually. @xref{Tagifying}, for information about creating a tag table. Visit the Info file you wish to tagify and split manually and type the two commands: @example M-x Info-tagify M-x Info-split @end example @noindent (Note that the @samp{I} in @samp{Info} is uppercase.) When you use the @code{Info-split} command, the buffer is modified into a (small) Info file which lists the indirect subfiles. This file should be saved in place of the original visited file. The indirect subfiles are written in the same directory the original file is in, with names generated by appending @samp{-} and a number to the original file name. The primary file still functions as an Info file, but it contains just the tag table and a directory of subfiles. @xref{Tag and Split Files}. @node Catching Mistakes @nodedescription How to find mistakes in formatting. @section Catching Mistakes @cindex Structure, catching mistakes in @cindex Nodes, catching mistakes @cindex Catching mistakes @cindex Correcting mistakes @cindex Mistakes, catching @cindex Problems, catching @cindex Debugging the Texinfo structure Besides mistakes in the content of your documentation, there are two kinds of mistake you can make with Texinfo: you can make mistakes with @@-commands, and you can make mistakes with the structure of the nodes and chapters. For finding problems with @@-commands, you can run @TeX{} or a region formatting command on the region that has a problem; indeed, you can run these commands on each region as you write it. For finding problems with the structure of nodes and chapters, you can use @kbd{C-c C-s} (@code{texinfo-show-structure}) and the related @code{occur} command and you can use the @kbd{M-x Info-validate} command. @node @command{texi2any} Preferred @nodedescription @command{texi2any} finds errors. @subsection @command{texi2any} Preferred @c anchor{makeinfo Preferred}@c prev name @anchor{@code{makeinfo} Preferred}@c prev name The @command{texi2any} program does an excellent job of catching errors and reporting them---far better than @code{texinfo-format-region} or @code{texinfo-format-buffer}. In addition, the various functions for automatically creating and updating node pointers and menus remove many opportunities for human error. Use @command{texi2any} (or its Texinfo mode manifestations, @code{makeinfo-region} and @code{makeinfo-buffer}) to format your file and check for other errors. This is the best way to work with Texinfo. But if you cannot use @command{texi2any}, or your problem is very puzzling, then you may want to use the tools described in this section. @node Debugging with Info @nodedescription How to catch errors with Info formatting. @subsection Catching Errors with Info Formatting @cindex Catching errors with Info formatting @cindex Debugging with Info formatting After you have written part of a Texinfo file, you can use the @code{texinfo-format-region} or the @code{makeinfo-region} command to see whether the region formats properly. Most likely, however, you are reading this section because for some reason you cannot use the @code{makeinfo-region} command; therefore, the rest of this section presumes that you are using @code{texinfo-format-region}. If you have made a mistake with an @@-command, @code{texinfo-format-region} will stop processing at or after the error and display an error message. To see where in the buffer the error occurred, switch to the @samp{*Info Region*} buffer; the cursor will be in a position that is after the location of the error. Also, the text will not be formatted after the place where the error occurred (or more precisely, where it was detected). For example, if you accidentally end a menu with the command @code{@@end menus} with an `s' on the end, instead of with @code{@@end menu}, you will see an error message that says: @example @@end menus is not handled by texinfo @end example @noindent The cursor will stop at the point in the buffer where the error occurs, or not long after it. The buffer will look like this: @example @group ---------- Buffer: *Info Region* ---------- * Menu: * Using texinfo-show-structure:: How to use `texinfo-show-structure' to catch mistakes. * Running Info-validate:: How to check for unreferenced nodes. @@end menus @point{} ---------- Buffer: *Info Region* ---------- @end group @end example The @code{texinfo-format-region} command sometimes provides slightly odd error messages. For example, the following cross-reference fails to format: @example (@@xref@{Catching Mistakes, for more info.) @end example @noindent In this case, @code{texinfo-format-region} detects the missing closing brace but displays a message that says @samp{Unbalanced parentheses} rather than @samp{Unbalanced braces}. This is because the formatting command looks for mismatches between braces as if they were parentheses. Sometimes @code{texinfo-format-region} fails to detect mistakes. For example, in the following, the closing brace is swapped with the closing parenthesis: @example (@@xref@{Catching Mistakes), for more info.@} @end example @noindent Formatting produces: @example (*Note for more info.: Catching Mistakes) @end example The only way for you to detect this error is to realize that the reference should have looked like this: @example (*Note Catching Mistakes::, for more info.) @end example Incidentally, if you are reading this node in Info and type @kbd{f @key{RET}} (@code{Info-follow-reference}), you will generate an error message that says: @example No such node: "Catching Mistakes) The only way @dots{} @end example @noindent This is because Info perceives the example of the error as the first cross-reference in this node and if you type a @key{RET} immediately after typing the Info @kbd{f} command, Info will attempt to go to the referenced node. If you type @kbd{f catch @key{TAB} @key{RET}}, Info will complete the node name of the correctly written example and take you to the `Catching Mistakes' node. (If you try this, you can return from the `Catching Mistakes' node by typing @kbd{l} (@code{Info-last}).) @node Debugging with @TeX{} @nodedescription How to catch errors with @TeX{} formatting. @subsection Debugging with @TeX{} @cindex Catching errors with @TeX{} formatting @cindex Debugging with @TeX{} formatting You can also catch mistakes when you format a file with @TeX{}. Usually, you will want to do this after you have run @code{texinfo-format-buffer} (or, better, @code{makeinfo-buffer}) on the same file, because @code{texinfo-format-buffer} sometimes displays error messages that make more sense than @TeX{}. (@xref{Debugging with Info}, for more information.) For example, @TeX{} was run on a Texinfo file, part of which is shown here: @example ---------- Buffer: texinfo.texi ---------- name of the Texinfo file as an extension. The @@samp@{??@} are `wildcards' that cause the shell to substitute all the raw index files. (@@xref@{sorting indices, for more information about sorting indices.) ---------- Buffer: texinfo.texi ---------- @end example @noindent (The cross-reference lacks a closing brace.) @TeX{} produced the following output, after which it stopped: @example ---------- Buffer: *tex-shell* ---------- Runaway argument? @{sorting indices, for more information about sorting indices.) @@ETC. ! Paragraph ended before @@xref was complete. <to be read again> @@par l.27 ? ---------- Buffer: *tex-shell* ---------- @end example In this case, @TeX{} produced an accurate and understandable error message: @example Paragraph ended before @@xref was complete. @end example @noindent @samp{@@par} is an internal @TeX{} command of no relevance to Texinfo. @samp{l.27} means that @TeX{} detected the problem on line 27 of the Texinfo file. The @samp{?} is the prompt @TeX{} uses in this circumstance. Unfortunately, @TeX{} is not always so helpful, and sometimes you must truly be a Sherlock Holmes to discover what went wrong. In any case, if you run into a problem like this, you can do one of three things. @enumerate @item You can tell @TeX{} to continue running and ignore just this error by typing @key{RET} at the @samp{?} prompt. @item You can tell @TeX{} to continue running and to ignore all errors as best it can by typing @kbd{r @key{RET}} at the @samp{?} prompt. This is often the best thing to do. However, beware: the one error may produce a cascade of additional error messages as its consequences are felt through the rest of the file. To stop @TeX{} when it is producing such an avalanche of error messages, type @kbd{C-c} (or @kbd{C-c C-c}, if you are running a shell inside Emacs). @item You can tell @TeX{} to stop this run by typing @kbd{x @key{RET}} at the @samp{?} prompt. @end enumerate If you are running @TeX{} inside Emacs, you need to switch to the shell buffer and line at which @TeX{} offers the @samp{?} prompt. Sometimes @TeX{} will format a file without producing error messages even though there is a problem. This usually occurs if a command is not ended but @TeX{} is able to continue processing anyhow. For example, if you fail to end an itemized list with the @code{@@end itemize} command, @TeX{} will write a DVI file that you can print out. The only error message that @TeX{} will give you is the somewhat mysterious comment: @example (@@end occurred inside a group at level 1) @end example @noindent However, if you print the DVI file, you will find that the text of the file that follows the itemized list is entirely indented as if it were part of the last item in the itemized list. The error message is the way @TeX{} says that it expected to find an @code{@@end} command somewhere in the file; but that it could not determine where it was needed. Another source of notoriously hard-to-find errors is a missing @code{@@end group} command. If you ever are stumped by incomprehensible errors, look for a missing @code{@@end group} command first. If the Texinfo file lacks header lines, @TeX{} may stop in the beginning of its run and display output that looks like the following. The @samp{*} indicates that @TeX{} is waiting for input. @example This is TeX, Version 3.14159 (Web2c 7.0) (test.texinfo [1]) * @end example @noindent In this case, simply type @kbd{\end @key{RET}} after the asterisk. Then write the header lines in the Texinfo file and run the @TeX{} command again. (Note the use of the backslash, @samp{\}. @TeX{} uses @samp{\} instead of @samp{@@}; and in this circumstance, you are working directly with @TeX{}, not with Texinfo.) @node Running @code{Info-validate} @nodedescription How to find badly referenced nodes. @subsection Finding Badly Referenced Nodes @anchor{Running Info-Validate}@c old name @findex Info-validate @cindex Nodes, checking for badly referenced @cindex Checking for badly referenced nodes @cindex Looking for badly referenced nodes @cindex Finding badly referenced nodes @cindex Badly referenced nodes You can use the @code{Info-validate} command to check whether any of the `Next', `Previous', `Up' or other node pointers fail to point to a node. This command checks that every node pointer points to an existing node. The @code{Info-validate} command works only on Info files, not on Texinfo files. The @command{texi2any} program validates pointers automatically, so you do not need to use the @code{Info-validate} command if you are using @command{texi2any}. With the customization variable @code{CHECK_NORMAL_MENU_STRUCTURE} set, @command{texi2any} will also warn if the nodes pointers (either explicitly or automatically set) are not consistent with the order of node menu entries. @command{texi2any} does not check that every `Next' pointer is matched by a `Previous' (in the node where the `Next' points) which points back, since it may be correct for a non standard document structure. You only may need to use @code{Info-validate} if you are unable to run @command{texi2any} and instead must create an Info file using @code{texinfo-format-region} or @code{texinfo-format-buffer}, or if you write an Info file from scratch. @node Using @code{Info-validate} @nodedescription How to run @code{Info-validate}. @subsubsection Using @code{Info-validate} @cindex Using @code{Info-validate} @cindex Info validating a large file @cindex Validating a large file To use @code{Info-validate}, visit the Info file you wish to check and type: @example M-x Info-validate @end example @noindent Note that the @code{Info-validate} command requires an uppercase `I'@. You may also need to create a tag table before running @code{Info-validate}. @xref{Tagifying}. If your file is valid, you will receive a message that says ``File appears valid''. However, if you have a pointer that does not point to a node, error messages will be displayed in a buffer called @samp{*problems in info file*}. For example, @code{Info-validate} was run on a test file that contained only the first node of this manual. One of the messages said: @example In node "Overview", invalid Next: Texinfo Mode @end example @noindent This meant that the node called @samp{Overview} had a `Next' pointer that did not point to anything (which was true in this case, since the test file had only one node in it). Now suppose we add a node named @samp{Texinfo Mode} to our test case but we do not specify a `Previous' for this node. Then we will get the following error message: @example In node "Texinfo Mode", should have Previous: Overview @end example @noindent This is because, with a standard document structure, every `Next' pointer should be matched by a `Previous' (in the node where the `Next' points) which points back. @code{Info-validate} also checks that all menu entries and cross-references point to actual nodes. @code{Info-validate} requires a tag table and does not work with files that have been split. (The @code{texinfo-format-buffer} command automatically splits large files.) In order to use @code{Info-validate} on a large file, you must run @code{texinfo-format-buffer} with an argument so that it does not split the Info file; and you must create a tag table for the unsplit file. @node Unsplit and Tagify @nodedescriptionblock How to create an unsplit file and add a tag table for validation. @end nodedescriptionblock @subsubsection Creating an Unsplit File and Adding a Tag Table @anchor{Unsplit} @c old name @cindex Creating an unsplit file @cindex Unsplit file creation You can run @code{Info-validate} only on a single Info file that has a tag table. The command will not work on the indirect subfiles that are generated when a master file is split. If you have a large file (longer than 300,000 bytes or so), you need to run the @code{texinfo-format-buffer} or @code{makeinfo-buffer} command in such @c FIXME probably always a tag table with makeinfo-buffer? a way that it does not create indirect subfiles. You will also need to create a tag table for the Info file. After you have done this, you can run @code{Info-validate} and look for badly referenced nodes. The first step is to create an unsplit Info file. To prevent @code{texinfo-format-buffer} from splitting a Texinfo file into smaller Info files, give a prefix to the @kbd{M-x texinfo-format-buffer} command: @example C-u M-x texinfo-format-buffer @end example @noindent or else @example C-u C-c C-e C-b @end example @noindent When you do this, @code{texinfo-format-buffer} will not split the file and will not create a tag table for it. After creating an unsplit Info file, you must create a tag table for it (@pxref{Tagifying}). Visit the unsplit Info file created by @code{texinfo-format-buffer} and type: @example M-x Info-tagify @end example The third step is to validate the Info file: @example M-x Info-validate @end example @noindent (Note the uppercase @samp{I} in @code{Info-validate}.) In brief, the steps are: @example @group C-u M-x texinfo-format-buffer M-x Info-tagify M-x Info-validate @end group @end example After you have validated the node structure, you can rerun @code{texinfo-format-buffer} in the normal way so it will construct a tag table and split the file automatically, or you can make the tag table and split the file manually (@pxref{Splitting}). @node Batch Formatting @nodedescription How to format for Info in Emacs batch mode. @section Batch Formatting @cindex Batch formatting for Info @cindex Info batch formatting You can format Texinfo files for Info using @code{batch-texinfo-format} and Emacs batch mode. You can run Emacs in batch mode from any shell, including a shell inside of Emacs. (@xref{Initial Options,,, emacs, The GNU Emacs Manual}.) Here is a shell command to format all the files that end in @file{.texinfo} in the current directory: @example emacs -batch -funcall batch-texinfo-format *.texinfo @end example @noindent Emacs processes all the files listed on the command line, even if an error occurs while attempting to format some of them. Run @code{batch-texinfo-format} only with Emacs in batch mode as shown; it is not interactive. It kills the batch mode Emacs on completion. @code{batch-texinfo-format} is convenient if you lack @command{texi2any} and want to format several Texinfo files at once. When you use Batch mode, you create a new Emacs process. This frees your current Emacs, so you can continue working in it. (When you run @code{texinfo-format-region} or @code{texinfo-format-buffer}, you cannot use that Emacs for anything else until the command finishes.) @node Global Document Commands @nodedescription Affecting formatting throughout. @appendix Global Document Commands @cindex Global Document Commands Here are additional commands which affect the document as a whole. Most of these commands are for customizing the appearance of the printed output. They are generally all given before the Top node, if they are given at all. @node @code{@@setchapternewpage} @nodedescription Start chapters on right-hand pages. @section @code{@@setchapternewpage}: Blank Pages Before Chapters @anchor{setchapternewpage}@c old name @findex setchapternewpage @cindex Starting chapters @cindex Pages, starting odd In an officially bound book, text is usually printed on both sides of the paper, chapters start on right-hand pages, and right-hand pages have odd numbers. But in short reports, text often is printed only on one side of the paper. Also in short reports, chapters sometimes do not start on new pages, but are printed on the same page as the end of the preceding chapter, after a small amount of vertical whitespace. You can use the @code{@@setchapternewpage} command with various arguments to specify how chapters should be started in printed output and whether headers should be formatted for printing on one or both sides of the paper (single-sided or double-sided printing). Write the @code{@@setchapternewpage} command at the beginning of a line followed by its argument. For example, you would write the following to cause each chapter to start on a fresh odd-numbered page: @example @@setchapternewpage odd @end example You can specify one of three alternatives with the @code{@@setchapternewpage} command: @table @asis @item @code{@@setchapternewpage off} Typeset a new chapter on the same page as the last chapter, after skipping some vertical whitespace. Also, format page headers for single-sided printing. @item @code{@@setchapternewpage on} Start new chapters on new pages and format page headers for single-sided printing. This is the form most often used for short reports or personal printing. This is the default. @item @code{@@setchapternewpage odd} Start new chapters on new, odd-numbered pages (right-handed pages) and typeset for double-sided printing. This is the form most often used for books and manuals. @end table Texinfo does not have a @code{@@setchapternewpage even} command, because there is no printing tradition of starting chapters or books on an even-numbered page. If you don't like the default headers that @code{@@setchapternewpage} sets, you can explicit control them with the @code{@@headings} command. @xref{@code{@@headings}}. At the beginning of a manual or book, pages are not numbered---for example, the title and copyright pages of a book are not numbered. By convention, table of contents and frontmatter pages are numbered with roman numerals and not in sequence with the rest of the document. The @code{@@setchapternewpage} has no effect in output formats that do not have pages, such as Info and HTML. We recommend not including any @code{@@setchapternewpage} command in your document source at all, since such desired pagination is not intrinsic to the document. For a particular hard copy run, if you don't want the default output (no blank pages, same headers on all pages) use the @option{--texinfo} option to @command{texi2dvi} to specify the output you want. @node Headings @section Page Headings @nodedescription Page headings. @anchor{Headings Introduced}@c old name @cindex Headings @cindex Footings @cindex Page numbering @cindex Page headings @cindex Formatting headings and footings Most printed manuals contain headings along the top of every page except the title and copyright pages. Some manuals also contain footings. @c HTML output also supports something like these, but in a @c completely different way: @pxref{Customizing HTML Page Layout}. Headings and footings have no meaning in Info or the other output formats. Texinfo provides two standard heading formats, one for manuals printed on one side of each sheet of paper, and the other for manuals printed on both sides of the paper. By default, nothing is specified for the footing of a Texinfo file, so the footing remains blank. Texinfo also has several heading and footing commands that you can use to generate your own heading and footing formats. In Texinfo, headings and footings are single lines at the tops and bottoms of pages; you cannot create multiline headings or footings. Each header or footer line is divided into three parts: a left part, a middle part, and a right part. Any part, or a whole line, may be left blank. Text for the left part of a header or footer line is set flushleft; text for the middle part is centered; and, text for the right part is set flushright. @node @code{@@headings} @nodedescriptionblock An option for turning headings on and off and double or single sided printing. @end nodedescriptionblock @subsection The @code{@@headings} Command @anchor{headings on off}@c old name @findex headings The @code{@@headings} command is rarely used. It specifies what kinds of page headings and footings to print on each page. Usually, this is controlled by the @code{@@setchapternewpage} command. You need the @code{@@headings} command only if the @code{@@setchapternewpage} command does not do what you want. You can use @code{@@headings} as follows: @table @code @item @@headings off Turn off printing of page headings. @item @@headings single Turn on page headings appropriate for single-sided printing. @item @@headings double Turn on page headings appropriate for double-sided printing. @item @@headings singleafter @itemx @@headings doubleafter Turn on @code{single} or @code{double} headings, respectively, after the current page is output. @item @@headings on Turn on page headings: @code{single} if @samp{@@setchapternewpage on}, @code{double} otherwise. @end table For example, suppose you write @code{@@setchapternewpage off} before the @code{@@titlepage} command to start a new chapter on the same page as the end of the last chapter. This command also causes page headers to be typeset for single-sided printing. To cause page headers to be typeset for double-sided printing, write @code{@@headings double}. You can stop any page headings at all from being generated by writing @code{@@headings off} on a line of its own, like this: @example @@headings off @end example @node Heading Format @nodedescription Standard page heading formats. @subsection Standard Heading Formats Texinfo provides two standard heading formats, one for manuals printed on one side of each sheet of paper, and the other for manuals printed on both sides of the paper. The standard format for single-sided printing consists of a header line in which the left-hand part contains the name of the chapter, the central part is blank, and the right-hand part contains the page number. A single-sided page looks like this: @example @group _______________________ | | | chapter page number | | | | Start of text ... | | ... | | | @end group @end example In the standard double-sided format, the left part of the left-hand (even-numbered) page contains the page number, the central part is blank, and the right part contains the title (specified by the @code{@@settitle} command). The left part of the right-hand (odd-numbered) page contains the name of the chapter, the central part is blank, and the right part contains the page number. An even-numbered page and an odd-numbered page, side by side as in an open book, look like this: @example @group _______________________ _______________________ | | | | | page number title | | chapter page number | | | | | | Start of text ... | | More text ... | | ... | | ... | | | | | @end group @end example @noindent The chapter name is preceded by the word ``Chapter'', the chapter number and a colon. This makes it easier to keep track of where you are in the manual. Note that on pages where a new chapter starts, some text may be omitted from the heading line. @ignore @c not germane to headings? we don't document \bindingoffset or \normaloffset @c anywhere. In double sided printing, @TeX{} will adjust the widths of the left- and right-hand margins. Usually, widths are correct, but during double-sided printing, it is wise to check that pages will bind properly---sometimes a printer will produce output in which the even-numbered pages have a larger right-hand margin than the odd-numbered pages.) @end ignore By default, nothing is specified for the footing of a Texinfo file, so the footing remains blank. @node Custom Headings @nodedescription How to create your own headings and footings. @subsection How to Make Your Own Headings You can use the standard headings provided with Texinfo or specify your own. By default, Texinfo has no footers, so if you specify them, the available page size for the main text will be slightly reduced. Texinfo provides six commands for specifying headings and footings: @itemize @bullet @item @code{@@everyheading} and @code{@@everyfooting} generate page headers and footers that are the same for both even- and odd-numbered pages. @item @code{@@evenheading} and @code{@@evenfooting} commands generate headers and footers for even-numbered (left-hand) pages. @item @code{@@oddheading} and @code{@@oddfooting} generate headers and footers for odd-numbered (right-hand) pages. @end itemize You must cancel the predefined heading commands with the @code{@@headings off} command before defining your own specifications. @need 1000 Here is how to place the chapter name at the left, the page number in the center, and the date at the right of every header for both even- and odd-numbered pages: @example @group @@headings off @@everyheading @@thischapter @@| @@thispage @@| @@today@{@} @end group @end example @noindent You need to divide the left part from the central part and the central part from the right part by inserting @samp{@@|} between parts. Otherwise, the specification command will not be able to tell where the text for one part ends and the next part begins. Each part can contain text or @@-commands. The text is printed as if the part were within an ordinary paragraph in the body of the page. The @@-commands replace themselves with the page number, date, chapter name, or whatever. @need 950 Here are the six heading and footing commands: @table @code @findex everyheading @findex everyfooting @item @@everyheading @var{left} @@| @var{center} @@| @var{right} @itemx @@everyfooting @var{left} @@| @var{center} @@| @var{right} The `every' commands specify the format for both even- and odd-numbered pages. These commands are for documents that are printed on one side of each sheet of paper, or for documents in which you want symmetrical headers or footers. @findex evenheading @findex evenfooting @findex oddheading @findex oddfooting @item @@evenheading @var{left} @@| @var{center} @@| @var{right} @itemx @@oddheading @var{left} @@| @var{center} @@| @var{right} @itemx @@evenfooting @var{left} @@| @var{center} @@| @var{right} @itemx @@oddfooting @var{left} @@| @var{center} @@| @var{right} The `even' and `odd' commands specify the format for even-numbered pages and odd-numbered pages. These commands are for books and manuals that are printed on both sides of each sheet of paper. @end table Use the @samp{@@this@dots{}} series of @@-commands to provide the names of chapters and sections and the page number. You can use the @samp{@@this@dots{}} commands in the left, center, or right portions of headers and footers. @need 1000 Here are the @samp{@@this@dots{}} commands: @table @code @findex thispage @item @@thispage Expands to the current page number. @findex thissectionname @item @@thissectionname Expands to the name of the current section. @findex thissectionnum @item @@thissectionnum Expands to the number of the current section. @findex thissection @item @@thissection Expands to the number and name of the current section, in the format `Section 1: Title'. @findex thischaptername @item @@thischaptername Expands to the name of the current chapter. @findex thischapternum @item @@thischapternum Expands to the number of the current chapter, or letter of the current appendix. @findex thischapter @item @@thischapter Expands to the number and name of the current chapter, in the format `Chapter 1: Title'. @findex thistitle @item @@thistitle Expands to the name of the document, as specified by the @code{@@settitle} command. @findex thisfile @item @@thisfile For @code{@@include} files only: expands to the name of the current @code{@@include} file. If the current Texinfo source file is not an @code{@@include} file, this command has no effect. This command does @emph{not} provide the name of the current Texinfo source file unless it is an @code{@@include} file. (@xref{Include Files}, for more information about @code{@@include} files.) @end table @noindent You can also use the @code{@@today@{@}} command, which expands to the current date, in `1 Jan 1900' format. @findex today Other @@-commands and text are printed in a header or footer just as if they were in the body of a page. It is useful to incorporate text, particularly when you are writing drafts: @example @group @@headings off @@everyheading @@emph@{Draft!@} @@| @@thispage @@| @@thischapter @@everyfooting @@| @@| Version: 0.27: @@today@{@} @end group @end example Beware of overlong titles: they may overlap another part of the header or footer and blot it out. If you have very short chapters and/or sections, several of them can appear on a single page. You can specify which chapters and sections you want @code{@@thischapter}, @code{@@thissection} and other such macros to refer to on such pages as follows: @table @code @findex everyheadingmarks @findex everyfootingmarks @item @@everyheadingmarks @var{ref} @itemx @@everyfootingmarks @var{ref} The @var{ref} argument can be either @code{top} (the @code{@@this...} commands will refer to the chapter/section at the top of a page) or @code{bottom} (the commands will reflect the situation at the bottom of a page). These @samp{@@every...} commands specify what to do on both even- and odd-numbered pages. @findex evenheadingmarks @findex oddheadingmarks @findex evenfootingmarks @findex oddfootingmarks @item @@evenheadingmarks @var{ref} @itemx @@oddheadingmarks @var{ref} @itemx @@evenfootingmarks @var{ref} @itemx @@oddfootingmarks @var{ref} These @samp{@@even...} and @samp{@@odd...} commands specify what to do on only even- or odd-numbered pages, respectively. The @var{ref} argument is the same as with the @samp{@@every...} commands. @end table Write these commands immediately after the @code{@@...contents} commands, or after the @code{@@end titlepage} command if you don't have a table of contents or if it is printed at the end of your manual. These commands have no effect in @LaTeX{}. By default, for @TeX{}, the @code{@@this...} commands reflect the situation at the bottom of a page both in headings and in footings. @node @code{@@paragraphindent} @nodedescription Specify paragraph indentation. @section @code{@@paragraphindent}: Controlling Paragraph Indentation @anchor{paragraphindent}@c old name @findex paragraphindent @cindex Indenting paragraphs, control of @cindex Paragraph indentation control The Texinfo processors may insert whitespace at the beginning of the first line of each paragraph, thereby indenting that paragraph. You can use the @code{@@paragraphindent} command to specify this indentation. Write a @code{@@paragraphindent} command at the beginning of a line followed by either @samp{asis} or a number: @example @@paragraphindent @var{indent} @end example The indentation is according to the value of @var{indent}: @table @asis @item @code{asis} Do not change the existing indentation (not implemented in printed output). @item @code{none} @itemx 0 Omit all indentation. @item @var{n} Indent by @var{n} space characters in Info output, by @var{n} ems in printed output. @end table The default value of @var{indent} is 3. @code{@@paragraphindent} is ignored for HTML output. It is best to write the @code{@@paragraphindent} command before the end-of-header line at the beginning of a Texinfo file, so the region formatting commands indent paragraphs as specified. @xref{Start of Header}. @node @code{@@firstparagraphindent} @nodedescription Suppressing first paragraph indentation. @section @code{@@firstparagraphindent}: Indenting After Headings @anchor{firstparagraphindent}@c old name @findex firstparagraphindent @cindex First paragraph, suppressing indentation of @cindex Suppressing first paragraph indentation @cindex Preventing first paragraph indentation @cindex Indenting, suppressing of first paragraph @cindex Headings, indentation after As you can see in the present manual, the first paragraph in any section is not indented by default. Typographically, indentation is a paragraph separator, which means that it is unnecessary when a new section begins. This indentation is controlled with the @code{@@firstparagraphindent} command: @example @@firstparagraphindent @var{word} @end example The first paragraph after a heading is indented according to the value of @var{word}: @table @asis @item @code{none} Prevents the first paragraph from being indented (default). This option is ignored by @command{makeinfo} if @code{@@paragraphindent asis} is in effect. @item @code{insert} Include normal paragraph indentation. This respects the paragraph indentation set by a @code{@@paragraphindent} command (@pxref{@code{@@paragraphindent}}). @end table @code{@@firstparagraphindent} is ignored for HTML and DocBook output. It is best to write the @code{@@firstparagraphindent} command before the end-of-header line at the beginning of a Texinfo file, so the region formatting commands indent paragraphs as specified. @xref{Start of Header}. @node @code{@@exampleindent} @nodedescription Specify environment indentation. @section @code{@@exampleindent}: Environment Indenting @anchor{exampleindent}@c old name @findex exampleindent @cindex Indenting environments @cindex Environment indentation @cindex Example indentation The Texinfo processors indent each line of @code{@@example} and similar environments. You can use the @code{@@exampleindent} command to specify this indentation. Write an @code{@@exampleindent} command at the beginning of a line followed by either @samp{asis} or a number: @example @@exampleindent @var{indent} @end example The indentation is according to the value of @var{indent}: @table @asis @item @code{asis} Do not change the existing indentation (not implemented in printed output). @item 0 Omit all indentation. @item @var{n} Indent environments by @var{n} space characters in Info output, by @var{n} ems in printed output. @end table The default value of @var{indent} is 5 spaces in Info, and 0.4@dmn{in} in printed output, which is somewhat less. (The reduction is to help fit more characters onto physical lines in printed manuals.) It is best to write the @code{@@exampleindent} command before the end-of-header line at the beginning of a Texinfo file, so the region formatting commands indent paragraphs as specified. @xref{Start of Header}. @node @code{@@smallbook} @nodedescription How to print small format books and manuals. @section @code{@@smallbook}: Printing ``Small'' Books @anchor{smallbook}@c old name @findex smallbook @cindex Small book size @cindex Book, printing small @cindex Page sizes for books @cindex Size of printed book By default, @TeX{} typesets pages for printing in an 8.5 by 11 inch format, which is the ``letter'' size commonly used in the United States. However, you can direct @TeX{} or @LaTeX{} to typeset a document in a 7 by 9.25 inch format that is suitable for bound books by inserting the following command on a line by itself at the beginning of the Texinfo file, before the title page: @example @@smallbook @end example @noindent (Since many books are about 7 by 9.25 inches, this command might better have been called the @code{@@regularbooksize} command, but it came to be called the @code{@@smallbook} command by comparison to the 8.5 by 11 inch format.) @xref{Format with @command{texi2dvi} or @command{texi2pdf}}, and @ref{Preparing for @TeX{}}, for other ways to format with @code{@@smallbook} with @TeX{} that do not require changing the source file. @node A4 Paper @nodedescription How to print on A4, A5 or B6 paper. @section Printing on A4 Paper @cindex A4 paper, printing on @cindex Paper size, A4 @cindex European A4 paper @findex afourpaper You can format a document for printing on ISO 216 A4 paper size with the @code{@@afourpaper} command. Write the command on a line by itself near the beginning of the Texinfo file, before the title page. @cindex A5 paper, printing on @findex afourlatex @findex afourwide @findex afivepaper @findex bsixpaper You may or may not prefer the formatting that results from the command @code{@@afourlatex}. There's also @code{@@afourwide} for A4 paper in wide format, @code{@@afivepaper} for A5 paper, and @code{@@bsixpaper} for B6 paper. @xref{Format with @command{texi2dvi} or @command{texi2pdf}} and @ref{Preparing for @TeX{}}, for other ways to format for different paper sizes that do not require changing the source file. @node @code{@@pagesizes} @nodedescription How to print with customized page sizes. @section @code{@@pagesizes} [@var{width}][, @var{height}]: Custom Page Sizes @anchor{pagesizes}@c old node name @findex pagesizes @cindex Custom page sizes @cindex Page sizes, customized @cindex Text width and height @cindex Width of text area @cindex Height of text area @cindex Depth of text area You can explicitly specify the height and (optionally) width of the main text area on the page with the @code{@@pagesizes} command. Write this on a line by itself near the beginning of the Texinfo file, before the title page. The height comes first, then the width if desired, separated by a comma. Examples: @example @@pagesizes 200mm,150mm @c for b5 paper @end example @noindent and @example @@pagesizes 11.5in @c for legal paper @end example @cindex B5 paper, printing on @cindex Legal paper, printing on This would be reasonable for printing on B5-size paper. To emphasize, this command specifies the size of the @emph{text area}, not the size of the paper (which is 250@dmn{mm} by 177@dmn{mm} for B5, 14@dmn{in} by 8.5@dmn{in} for legal). @cindex Margins on page, not controllable To make more elaborate changes, such as changing any of the page margins, you must define a new command in @file{texinfo.tex} or @file{texinfo.cnf}. @xref{Format with @command{texi2dvi} or @command{texi2pdf}}, and @ref{Preparing for @TeX{}}, for other ways to specify @code{@@pagesizes} that do not require changing the source file. @node Microtypography @nodedescription Improving the appearance of paragraphs. @section Microtypography Some versions of @TeX{}, namely pdf@TeX{} and Lua@TeX{}, have @dfn{microtypography} features. These involve stretching font glyphs slightly, and allowing text to produce very slightly into the margins. Use of these gives @TeX{} more flexibility in breaking a paragraph into lines, and can improve paragraph appearance by reducing hyphenation and producing a more consistent typographic color. @findex microtype @file{texinfo.tex} uses these features (`microtype' for short) when available. You can turn microtype off by specifying @samp{@@microtype off} in your input file; likewise, @samp{@@microtype on} turns microtype back on. @cindex CM-Super fonts @subentry for @LaTeX{} The fonts used in @LaTeX{} output may not be scalable. If fonts are not scalable, using microtypography could trigger an error when converting the @LaTeX{} output. Therefore microtypography is not turned on in the default case in @LaTeX{} output. It is possible to turn it on with @samp{@@microtype on}. A way to get scalable fonts for the font used in the default @LaTeX{} output is to install the CM-Super font package (@url{http://ctan.org/pkg/cm-super}). The @code{@@microtype} command does nothing for other output formats. @node Magnification @nodedescription How to print scaled up output. @section Magnification @anchor{Cropmarks and Magnification} @c old name @findex \mag @r{(raw @TeX{} magnification)} @cindex Magnified printing @cindex Larger or smaller pages You can attempt to direct @TeX{} to typeset pages larger or smaller than usual with the @code{\mag} @TeX{} command. Everything that is typeset is scaled proportionally larger or smaller. (@code{\mag} stands for ``magnification''.) This is @emph{not} a Texinfo @@-command, but is a raw @TeX{} command that is prefixed with a backslash. You have to write this command between @code{@@tex} and @code{@@end tex} (@pxref{Raw Formatter Commands}). Follow the @code{\mag} command with an @samp{=} and then a number that is 1000 times the magnification you desire. For example, to print pages at 1.2 normal size, write the following near the beginning of the Texinfo file, before the title page: @example @group @@tex \global\mag=1200 @@end tex @end group @end example With some printing technologies, you can print normal-sized copies that look better than usual by giving a larger-than-normal master to your print shop. They do the reduction, thus effectively increasing the resolution. Depending on your system, DVI files prepared with a nonstandard-@code{\mag} may not print or may print only with certain magnifications. Be prepared to experiment. @node Info Format Specification @nodedescription Technical details of the Info file format. @appendix Info Format Specification @cindex Info format specification @cindex Specification of Info format @cindex Definition of Info format Here we describe the technical details of the Info format. In this formal description, the characters @code{<>*()|=#} are used for the language of the description itself. Other characters are literal. The formal constructs used are typical: @code{<...>} indicates a metavariable name, @samp{=} means definition, @samp{*} repetition, @samp{?} optional, @samp{()} grouping, @samp{|} alternation, and @samp{#} comment. @c Exception: @samp{*} at the beginning of a line is literal. @c (Is it really worth stating this?) In general, programs that read Info files should try to be case-insensitive to keywords that occur in the file (for example, @samp{Tag Table} and @samp{Tag table} should be equivalent) in order to support Info-generating programs that use different capitalization. We specify literal parentheses (those that are part of the Info format) with @t{<lparen>} and @t{<rparen>}, meaning the single characters @samp{(} and @samp{)} respectively. Finally, the two-character sequence @samp{^@var{x}} means the single character @samp{CTRL-@var{x}}, for any @var{x}. This format definition was written some 25 years after the Info format was first devised. So in the event of conflicts between this definition and actual practice, practice wins. It also assumes some general knowledge of Texinfo; it is meant to be a guide for implementors rather than a rigid technical standard. We may refer back to other parts of this manual for examples and definitions, rather than redundantly spelling out every detail. @menu * Whole: Info Format Whole Manual. * Preamble: Info Format Preamble. * Indirect: Info Format Indirect Table. * Tag table: Info Format Tag Table. * Local variables: Info Format Local Variables. * Regular nodes: Info Format Regular Nodes. * Menu: Info Format Menu. * Image: Info Format Image. * Printindex: Info Format Printindex. * Cross-Reference: Info Format Cross Reference. @end menu @node Info Format Whole Manual @nodedescription Split vs.@: nonsplit manuals. @section Info Format: A Whole Manual @cindex Nonsplit manuals, Info format of @cindex Split manuals, Info format of @cindex Whole manual, in Info format To begin, an Info manual is either @dfn{nonsplit} (contained wholly within a single file) or @dfn{split} (across several files). The syntax for a nonsplit manual is: @example <nonsplit info file> = <preamble> <node>* <tag table>? <local variables>? @end example When split, there is a @dfn{main file}, which contains only pointers to the nodes given in other @dfn{subfiles}. The main file looks like this: @example <split info main file> = <preamble> <indirect table> <tag table> <local variables>? @end example The subfiles in a split manual have the following syntax: @example <split info subfile> = <preamble> <node>* @end example Note that the tag table is not optional for split files, as it is used with the indirect table to deduce which subfile a particular node is in. Several of the sections in an Info file (such as nodes or tag tables) begin with a sequence: @example <separator> = (^L)?^_(^L)?^J @end example @noindent That is, a @samp{CTRL-_} character followed by a newline, with optional formfeed characters. @node Info Format Preamble @section Info Format: Preamble @cindex Preamble, in Info format The @t{<preamble>} is text at the beginning of all output files. It is not intended to be visible by default in an Info viewer, but may be displayed upon user request. @example <preamble> = <identification> # "This is FILENAME, produced by ..." <copying text> # Expansion of @@copying text. <dir entries> # Derived from @@dircategory and @@direntry. @end example @noindent These pieces are: @table @t @item <identification line> An arbitrary string beginning the output file, followed by a blank line. @item <copying text> The expansion of a @code{@@copying} environment, if the manual has one (@pxref{@code{@@copying}}). @item <dir entries> The result of any @code{@@dircategory} and @code{@@direntry} commands present in the manual (@pxref{Installing Dir Entries}). @end table @node Info Format Indirect Table @section Info Format: Indirect Table @cindex Indirect table, in Info format @example <indirect table> = <separator> Indirect: (<filename>: <bytepos>)* @end example The indirect table is written to the main file in the case of split output only. It specifies, as a decimal integer, the starting byte position (zero-based) that the first node of each subfile would have if the subfiles were concatenated together in order, not including the top-level file. The first node of actual content is pointed to by the first entry. As an example, suppose split output is generated for the GDB manual. The top-level file @file{gdb.info} will contain something like this: @example <separator> Indirect: gdb.info-1: 1878 gdb.info-2: 295733 ... @end example This tells Info viewers that the first node of the manual occurs at byte 1878 of the file @file{gdb.info-1} (which would be after that file's preamble.) The first node in the @file{gdb.info-2} subfile would start at byte 295733 if @file{gdb.info-2} were appended to @file{gdb.info-1}, including any preamble sections in both files. Unfortunately, Info-creating programs such as @command{makeinfo} have not always implemented these rules perfectly, due to various bugs and oversights. Therefore, robust Info viewers should fall back to searching ``nearby'' the given position for a node, instead of giving up immediately if the position is not exactly at a node beginning. @node Info Format Tag Table @section Info Format: Tag Table @cindex Tag table, in Info format @example <tag table> = <separator> Tag Table: (<lparen>Indirect<rparen>)? (Node|Ref): <nodeid>^?<bytepos> <separator> End Tag Table @end example The @samp{(Indirect)} line appears in the case of split output only. The tag table specifies the starting byte position of each node and anchor in the file. In the case of split output, it is only written in the main output file. Each line defines an identifier as either an anchor or a node, as specified. For example, @samp{Node: Top^?1647} says that the node named @samp{Top} starts at byte 1647 while @samp{Ref: Overview-Footnote-1^?30045} says that the anchor named @samp{Overview-Footnote-1} starts at byte 30045. It is an error to define the same identifier both ways. In the case of nonsplit output, the byte positions simply refer to the location in the output file. In the case of split output, the byte positions refer to an imaginary file created by concatenating all the split files (but not the top-level file). See the previous section. Here is an example: @example ^_ Tag Table: Node: Top^?89 Node: Ch1^?292 ^_ End Tag Table @end example @noindent This specifies a manual with two nodes, `Top' and `Ch1', at byte positions 89 and 292 respectively. Because the @samp{(Indirect)} line is not present, the manual is not split. Preamble sections or other non-node sections of files do not have a tag table entry. @node Info Format Local Variables @section Info Format: Local Variables @cindex Local variable section, in Info format The local variables section is optional and is currently used to give the encoding information. It may be augmented in the future. @example <local variables> = <separator> Local Variables: coding: <encoding> End: @end example @xref{@code{@@documentencoding}}. @node Info Format Regular Nodes @section Info Format: Regular Nodes @cindex Info nodes, in Info format Regular nodes look like this: @example <node> = <separator> File: <fn>, Node: <id1>, (Next: <id2>, )? (Prev: <id3>, )? Up: <id4> <general text, until the next ^_ or end-of-file> @end example @noindent At least one space or tab must be present after each colon and comma, but any number of spaces are ignored. The @t{<id>} node identifiers have following format: @example <id> = (<lparen><infofile><rparen>)?<node-spec>? <node-spec> = <nodename> | <del><nodename><del> <del> = ^? @end example This @t{<node>} defines @t{<id1>} in file @t{<fn>}, which is typically either @samp{manualname} or @samp{manualname.info}. No parenthesized @t{<infofile>} component may appear within @t{<id1>}. Each of the identifiers after @code{Next}, @code{Prev} and @code{Up} refer to nodes or anchors within a file. These pointers normally refer within the same file, but @samp{(dir)} is often used to point to the top-level dir file. If an @t{<infofile>} component is used then the node name may be omitted, in which case the node identifier refers to the @samp{Top} node within the referenced file. The @code{Next} and @code{Prev} pointers are optional. The @code{Up} pointer is technically also optional, although most likely this indicates a mistake in the node structuring. Conventionally, the nodes are arranged to form a tree, but this is not a requirement of the format. Node names containing periods, commas, colons or parentheses can confuse Info readers. If it is necessary to refer to a node whose name contains any of these, the @t{<nodename>} should be surrounded by a pair of @code{DEL} characters (@samp{CTRL-?}, character number 127). @command{makeinfo} adds these characters when needed in the default case. Note that not all Info readers recognize this syntax. @xref{Info Node Names Constraints}. The @t{<general text>} of the node can include the special constructs described next. @node Info Format Menu @section Info Format: Menu @cindex Menus, in Info format Conventionally menus appear at the end of nodes, but the Info format places no restrictions on their location. @example <menu> = * Menu: (<menu entry> | <menu comment>)* @end example The parts of a @t{<menu entry>} are also described in @ref{Menu Parts}. They have the same syntax as cross-references, with a leading @samp{*} instead of @samp{* (N|n)ote} (@pxref{Info Format Cross Reference}). Indices extend the menu format to specify the destination line; @pxref{Info Format Printindex}. A @t{<menu comment>} is any line not beginning with @samp{*} that appears either at the beginning of the menu or is separated from a menu entry by one or more blank lines. These comments are intended to be displayed as part of the menu, as-is (@pxref{Writing a Menu}). @node Info Format Image @section Info Format: Image @cindex Images @subentry in Info format The @code{@@image} command results in the following special directive within the Info file (@pxref{Images}): @example <image> = ^@@^H[image src="<image file>" (text="<txt file contents>")? (alt="<alt text>")? ^@@^H] @end example The line breaks and indentation in this description are editorial; the whitespace between the different parts of the directive in Info files is arbitrary. In the strings @t{<image file>}, @t{<txt file contents>} and @t{<alt text>}, @samp{"} is quoted as @samp{\"} and @samp{\} is quoted as @samp{\\}. The txt and alt specifications are optional. The @t{alt} value serves the same purpose as in HTML: A prose description of the image. In text-only displays or speech systems, for example, the @t{alt} value may be used instead of displaying the (typically graphical) @t{<image file>}. The @t{<txt file contents>}, if present, should be taken as an ASCII representation of the image, for possible use on a text-only display. The format does not prescribe the choice between displaying the @t{<image file>}, the @t{<alt text>} or the @t{<txt file contents>}. @node Info Format Printindex @section Info Format: Printindex @cindex Indices, in Info format An index in Info format is a kind of menu, with an additional directive at the beginning to mark it as an index menu. @example <printindex> = ^@@^H[index^@@^H] * Menu: <index entry>* @end example The @t{<index entry>} items are similar to normal menu entries, but the free-format description is replaced by the line number of where the entries occurs in the text: @example <index entry> = * <entry text>: <node-spec>. <line-spec> <line-spec> = <lparen>line <lineno><rparen> @end example @noindent The initial part, @samp{<entry text>: <entry node>.}, should be on a single line. The @t{<entry text>} is the index term. Even though @t{<entry text>} is followed by a colon, it may itself contain colons, so Info readers should try to include as much of the line as possible in the @t{<entry text>}. (However, @t{<entry text>} may not contain the @code{DEL} characters that may occur in @t{<node-spec>}.) @t{<lineno>} is an unsigned integer, given relative to the start of the @t{<entry node>}. An optional line break may occur before @samp{<line-spec>}. Here is an example: @example ^@@^H[index^@@^H] * Menu: * thunder: Weather Phenomena. (line 5) @end example This means that an index entry for `thunder' appears at line 5 of the node `Weather Phenomena'. @node Info Format Cross Reference @section Info Format: Cross-reference @cindex Cross-references, in Info format A general cross-reference in Info format has one of the following two forms: @example <cross-reference> = * (N|n)ote <id>:: @c| * (N|n)ote <label>:<id>(.|,)? | * (N|n)ote <label>:<id>(.|,) <id> = (<lparen><infofile><rparen>)?<node-spec>? <label> = <label text> | <del><label text><del> @end example No space should occur between the @samp{*} character and the following @samp{N} or @samp{n}. @samp{*Note} should be used at the start of a sentence, otherwise @samp{*note} should be used. (Some Info readers, such as the one in Emacs, can display @samp{*Note} and @samp{*note} as @samp{See} and @samp{see} respectively.) In both cases, @t{<label text>} is descriptive text. In both forms the @t{<id>} refers to a node or anchor, in the same way as a reference in the node information line does (@pxref{Info Format Regular Nodes}). The optional parenthesized @samp{<infofile>} is the name of the manual being referenced, and @t{<node-spec>} gives the node or anchor within that manual. The second form has a descriptive label. A cross-reference in this form should usually be terminated with a comma or period, to make it feasible to find the end of the @t{<id>}. If @t{<label>} contains a colon character (@t{:}), it should be surrounded with a pair of @t{<del>} characters. Likewise, quoting characters may be used for the node name if it contains problematic characters; then a terminating comma or period is not needed. As stated earlier, this quoting mechanism is not supported in all Info-reading programs. The format does not prescribe how to find other manuals to resolve such references. Here are some examples: @example *note GNU Free Documentation License:: *note Tag table: Info Format Tag Table, for details. *Note Overview: (make)Top. *Note ^?:^?: (bash)Bourne Shell Builtins. *Note alloca.h: (gnulib)^?alloca.h^?. @end example The first shows a reference to a node in the current manual using the short form. The second also refers to a node in the current manual, namely `Info Format Tag Table'; the `Tag table' before the @samp{:} is only a label on this particular reference, and the @samp{for details.} is text belonging to the sentence, not part of the reference. The third example refers to the node `Top' in another manual, namely @samp{make}, with `Overview' being the label for this cross-reference. The fourth example shows a colon character being quoted in a label, and the fifth example shows a period being quoted in a node name. @xref{Cross References}. @node GNU Free Documentation License @nodedescription Copying this manual. @appendix GNU Free Documentation License @include fdl.texi @node Command and Variable Index @unnumbered Command and Variable Index This is an alphabetical list of all the @@-commands, assorted Emacs Lisp functions, and several variables. To make the list easier to use, the commands are listed without their preceding @samp{@@}. @printindex fn @node General Index @nodedescription A menu covering many topics. @unnumbered General Index @printindex cp @bye