\input texinfo.tex @c -*-texinfo-*- @c Everything between the start/end of header lines will be passed by @c Emacs's {texinfo,makeinfo}-format region commands. See the `start of @c header' node for more info. @c %**start of header @c Automake requires this @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 @comment %**end of header @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, 1990, 1991, 1992, 1993, 1995, 1996, 1997, 1998, 1999, 2001, 2001, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019 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 * Texinfo: (texinfo). The GNU documentation format. * install-info: (texinfo)Invoking install-info. Update info/dir entries. * makeinfo: (texinfo)Invoking makeinfo. 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 @c Set smallbook if printing in smallbook format so the example of the @c smallbook font is actually written using smallbook; in bigbook, a kludge @c is used for TeX output. Do this through the -t option to texi2dvi, @c so this same source can be used for other paper sizes as well. @c smallbook @c set smallbook @c @@clear smallbook @c If you like blank pages, add through texi2dvi -t. @c setchapternewpage odd @set txiindexatsignignore @set txiindexbackslashignore @set txiindexlessthanignore @set txiindexhyphenignore @titlepage @title Texinfo @subtitle The GNU Documentation Format @subtitle for Texinfo version @value{VERSION}, @value{UPDATED} @author Robert J. Chassell @author Richard M. Stallman @c Include the Distribution inside the titlepage so @c that headings are turned off. @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. @sp 1 Cover art by Etienne Suvasa. @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 @menu * Copying Conditions:: Your rights. * Overview:: Texinfo in brief. * Writing a Texinfo File:: Format of a Texinfo source file. * Beginning and Ending a File:: Beginning and end of a Texinfo file. * Nodes:: Writing nodes, the basic unit of Texinfo. * Chapter Structuring:: Creating chapters, sections, appendices, etc. * Cross References:: Writing cross-references. * Marking Text:: Marking words and phrases as code, keyboard input, meta-syntactic variables, and the like. * Quotations and Examples:: Block quotations, examples, etc. * Lists and Tables:: Itemized or numbered lists, and tables. * Special Displays:: Floating figures and footnotes. * Indices:: Creating indices. * Insertions:: Inserting @@-signs, braces, etc. * Breaks:: Forcing or preventing line and page breaks. * Definition Commands:: Describing functions and the like uniformly. * Internationalization:: Supporting languages other than English. * Conditionals:: Specifying text for only some output cases. * Defining New Texinfo Commands:: User-defined macros and aliases. * Include Files:: How to incorporate other Texinfo files. * Hardcopy:: Output for paper, with @TeX{}. * Generic Translator @command{texi2any}:: @command{texi2any}, an all-purpose converter. * Creating and Installing Info Files:: Details on Info output. * Generating HTML:: Details on HTML output. @c * texi2any Output Customization:: Fine tuning with initialization files. Appendices * @@-Command Details:: Details of the Texinfo @@-commands. * Tips:: Hints on how to write a Texinfo document. * Sample Texinfo Files:: Complete examples, including full texts. * Texinfo Mode:: Using the GNU Emacs Texinfo mode. * Headings:: How to write page headings and footings. * Catching Mistakes:: How to find mistakes in formatting. * Info Format Specification:: Technical details of the Info file format. * GNU Free Documentation License:: Copying this manual. * Command and Variable Index:: A menu containing commands and variables. * General Index:: A menu covering many topics. @detailmenu --- The Detailed Node Listing --- Overview of Texinfo * Reporting Bugs:: Submitting effective bug reports. * Output Formats:: Overview of the supported output formats. * Info Files:: What is an Info file? * Printed Books:: Characteristics of a printed book or manual. * Adding Output Formats:: Man pages and implementing new formats. * History:: Acknowledgements, contributors and genesis. Writing a Texinfo File * Command Syntax:: @@-commands are used for formatting. * Conventions:: General rules for writing a Texinfo file. * Comments:: Writing comments and ignored text in general. * Minimum:: What a Texinfo file must have. * Short Sample:: A short sample Texinfo file. Beginning and Ending a Texinfo File * Sample Beginning:: A sample beginning for a Texinfo file. * Texinfo File Header:: The first lines. * Document Permissions:: Ensuring your manual is free. * Titlepage & Copyright Page:: Creating the title and copyright pages. * Contents:: How to create a table of contents. * The Top Node:: Creating the `Top' node and master menu. * Global Document Commands:: Affecting formatting throughout. * Ending a File:: What is at the end of a Texinfo file? Texinfo File Header * First Line:: The first line of a Texinfo file. * Start of Header:: Formatting a region requires this. * @code{@@setfilename}:: Tell Info the name of the Info file. * @code{@@settitle}:: Create a title for the printed work. * End of Header:: Formatting a region requires this. Document Permissions * @code{@@copying}:: Declare the document's copying permissions. * @code{@@insertcopying}:: Where to insert the permissions. Title and Copyright Pages * @code{@@titlepage}:: Create a title for the printed document. * @code{@@titlefont @@center @@sp}:: The @code{@@titlefont}, @code{@@center}, and @code{@@sp} commands. * @code{@@title @@subtitle @@author}:: The @code{@@title}, @code{@@subtitle}, and @code{@@author} commands. * Copyright:: How to write the copyright notice and include copying permissions. * Heading Generation:: Turn on page headings after the title and copyright pages. The `Top' Node and Master Menu * Top Node Example:: * Master Menu Parts:: Global Document Commands * @code{@@documentdescription}:: Document summary for the HTML output. * @code{@@setchapternewpage}:: Start chapters on right-hand pages. * @code{@@headings}:: An option for turning headings on and off and double or single sided printing. * @code{@@paragraphindent}:: Specify paragraph indentation. * @code{@@firstparagraphindent}:: Suppressing first paragraph indentation. * @code{@@exampleindent}:: Specify environment indentation. Nodes * Texinfo Document Structure:: How Texinfo manuals are usually arranged. * Node Names:: How to choose node names. * Writing a Node:: How to write an @code{@@node} line. * Node Line Requirements:: Keep names unique. * First Node:: How to write a `Top' node. * @code{@@top} Command:: How to use the @code{@@top} command. * Node Menu Illustration:: A diagram, and sample nodes and menus. * @command{makeinfo} Pointer Creation:: Letting makeinfo determine node pointers. * Menus:: Listing subordinate nodes. Menus * Writing a Menu:: What is a menu? * Menu Example:: Two and three part menu entries. * Menu Location:: Menus go at the ends of nodes. * Menu Parts:: A menu entry has three parts. * Less Cluttered Menu Entry:: Two part menu entry. * Other Info Files:: How to refer to a different Info file. Chapter Structuring * Tree Structuring:: A manual is like an upside down tree @dots{} * Structuring Command Types:: How to divide a manual into parts. * @code{@@chapter}:: Chapter structuring. * @code{@@unnumbered @@appendix}:: * @code{@@majorheading @@chapheading}:: * @code{@@section}:: * @code{@@unnumberedsec @@appendixsec @@heading}:: * @code{@@subsection}:: * @code{@@unnumberedsubsec @@appendixsubsec @@subheading}:: * @code{@@subsubsection}:: Commands for the lowest level sections. * @code{@@part}:: Collections of chapters. * Raise/lower sections:: How to change commands' hierarchical level. Cross-references * References:: What cross-references are for. * Cross Reference Commands:: A summary of the different commands. * Cross Reference Parts:: A cross-reference has several parts. * @code{@@xref}:: Begin a reference with `See' @dots{} * Referring to a Manual as a Whole:: Refer to an entire manual. * @code{@@ref}:: A reference for the last part of a sentence. * @code{@@pxref}:: How to write a parenthetical cross-reference. * @code{@@anchor}:: Defining arbitrary cross-reference targets * @code{@@inforef}:: How to refer to an Info-only file. * @code{@@url}:: How to refer to a uniform resource locator. * @code{@@cite}:: How to refer to books not in the Info system. @code{@@xref} * One Argument:: @code{@@xref} with one argument. * Two Arguments:: @code{@@xref} with two arguments. * Three Arguments:: @code{@@xref} with three arguments. * Four and Five Arguments:: @code{@@xref} with four and five arguments. @code{@@url}, @code{@@uref@{@var{url}[, @var{text}][, @var{replacement}]@}} * @code{@@url} Examples:: Examples of using all the forms of @code{@@url}. * URL Line Breaking:: How lines are broken within @code{@@url} text. * @code{@@url} PDF Output Format:: A special option to hide links in PDF output. * PDF Colors:: Colorizing urls and other links in PDF output. Marking Text, Words and Phrases * Indicating:: How to indicate definitions, files, etc. * Emphasis:: How to emphasize text. Indicating Definitions, Commands, etc. * Useful Highlighting:: Highlighting provides useful information. * @code{@@code}:: Indicating program code. * @code{@@kbd}:: Showing keyboard input. * @code{@@key}:: Specifying keys. * @code{@@samp}:: Indicating a literal sequence of characters. * @code{@@verb}:: Indicating a verbatim sequence of characters. * @code{@@var}:: Indicating metasyntactic variables. * @code{@@env}:: Indicating environment variables. * @code{@@file}:: Indicating file names. * @code{@@command}:: Indicating command names. * @code{@@option}:: Indicating option names. * @code{@@dfn}:: Specifying definitions. * @code{@@abbr}:: Indicating abbreviations. * @code{@@acronym}:: Indicating acronyms. * @code{@@indicateurl}:: Indicating an example url. * @code{@@email}:: Indicating an electronic mail address. Emphasizing Text * @code{@@emph @@strong}:: How to emphasize text in Texinfo. * Smallcaps:: How to use the small caps font. * Fonts:: Various font commands for printed output. Quotations and Examples * Block Enclosing Commands:: Different constructs for different purposes. * @code{@@quotation}:: Writing a quotation. * @code{@@indentedblock}:: Block of text indented on left. * @code{@@example}:: Writing an example in a fixed-width font. * @code{@@verbatim}:: Writing a verbatim example. * @code{@@verbatiminclude}:: Including a file verbatim. * @code{@@lisp}:: Illustrating Lisp code. * @code{@@small@dots{}}:: Examples in a smaller font. * @code{@@display}:: Writing an example in the current font. * @code{@@format}:: Writing an example without narrowed margins. * @code{@@exdent}:: Undo indentation on a line. * @code{@@flushleft @@flushright}:: Pushing text flush left or flush right. * @code{@@raggedright}:: Avoiding justification on the right. * @code{@@noindent}:: Preventing paragraph indentation. * @code{@@indent}:: Forcing paragraph indentation. * @code{@@cartouche}:: Drawing rounded rectangles around text. Lists and Tables * Introducing Lists:: Texinfo formats lists for you. * @code{@@itemize}:: How to construct a simple list. * @code{@@enumerate}:: How to construct a numbered list. * Two-column Tables:: How to construct a two-column table. * Multi-column Tables:: How to construct generalized tables. Making a Two-column Table * @code{@@table}:: How to construct a two-column table. * @code{@@ftable @@vtable}:: Automatic indexing for two-column tables. * @code{@@itemx}:: How to put more entries in the first column. @code{@@multitable}: Multi-column Tables * Multitable Column Widths:: Defining multitable column widths. * Multitable Rows:: Defining multitable rows, with examples. Special Displays * Floats:: Figures, tables, and the like. * Images:: Including graphics and images. * Footnotes:: Writing footnotes. Floats * @code{@@float}:: Producing floating material. * @code{@@caption @@shortcaption}:: Specifying descriptions for floats. * @code{@@listoffloats}:: A table of contents for floats. Inserting Images * Image Syntax:: * Image Scaling:: Footnotes * Footnote Commands:: How to write a footnote in Texinfo. * Footnote Styles:: Controlling how footnotes appear in Info. Indices * Index Entries:: Choose different words for index entries. * Predefined Indices:: Use different indices for different kinds of entries. * Indexing Commands:: How to make an index entry. * Advanced Indexing:: Advanced indexing commands. * Printing Indices & Menus:: How to print an index in hardcopy and generate index menus in Info. * Combining Indices:: How to combine indices. * New Indices:: How to define your own indices. Combining Indices * @code{@@syncodeindex}:: How to merge two indices, using @code{@@code} font for the merged-from index. * @code{@@synindex}:: How to merge two indices, using the roman font for the merged-from index. Special Insertions * Special Characters:: Inserting @@ @{@} , \ # & * Inserting Quote Characters:: Inserting left and right quotes, in code. * Inserting Space:: Inserting the right amount of whitespace. * Inserting Accents:: Inserting accents and special characters. * Inserting Quotation Marks:: Inserting quotation marks. * Inserting Subscripts and Superscripts:: Inserting sub/superscripts. * Inserting Math:: Formatting mathematical expressions. * Glyphs for Text:: Inserting dots, bullets, currencies, etc. * Glyphs for Programming:: Indicating results of evaluation, expansion of macros, errors, etc. * Inserting Unicode:: Inserting a Unicode character by code point. Special Characters: Inserting @@ @{@} , \ # & * Inserting an Atsign:: @code{@@@@}, @code{@@atchar@{@}}. * Inserting Braces:: @code{@@@{ @@@}}, @code{@@l rbracechar@{@}}. * Inserting a Comma:: , and @code{@@comma@{@}}. * Inserting a Backslash:: \ and @code{@@backslashchar@{@}}. * Inserting a Hashsign:: # and @code{@@hashchar@{@}}. * Inserting an Ampersand:: & and @code{@@ampchar@{@}}. Inserting Space * Multiple Spaces:: Inserting multiple spaces. * Not Ending a Sentence:: Sometimes a . doesn't end a sentence. * Ending a Sentence:: Sometimes it does. * @code{@@frenchspacing}:: Specifying end-of-sentence spacing. * @code{@@dmn}:: Formatting a dimension. Glyphs for Text * @code{@@TeX @@LaTeX}:: The @TeX{} logos. * @code{@@copyright}:: The copyright symbol (c in a circle). * @code{@@registeredsymbol}:: The registered symbol (R in a circle). * @code{@@dots}:: How to insert ellipses: @dots{} and @enddots{} * @code{@@bullet}:: How to insert a bullet: @bullet{} * @code{@@euro}:: How to insert the euro currency symbol. * @code{@@pounds}:: How to insert the pounds currency symbol. * @code{@@textdegree}:: How to insert the degrees symbol. * @code{@@minus}:: How to insert a minus sign. * @code{@@geq @@leq}:: How to insert greater/less-than-or-equal signs. Glyphs for Programming * Glyphs Summary:: * @code{@@result}:: How to show the result of expression. * @code{@@expansion}:: How to indicate an expansion. * @code{@@print}:: How to indicate generated output. * @code{@@error}:: How to indicate an error message. * @code{@@equiv}:: How to indicate equivalence. * @code{@@point}:: How to indicate the location of point. * Click Sequences:: Inserting GUI usage sequences. Forcing and Preventing Breaks * Break Commands:: Summary of break-related commands. * Line Breaks:: Forcing line breaks. * @code{@@- @@hyphenation}:: Helping @TeX{} with hyphenation points. * @code{@@allowcodebreaks}:: Controlling line breaks within @@code text. * @code{@@w}:: Preventing unwanted line breaks in text. * @code{@@tie}:: Inserting an unbreakable but varying space. * @code{@@sp}:: Inserting blank lines. * @code{@@page}:: Forcing the start of a new page. * @code{@@group}:: Preventing unwanted page breaks. * @code{@@need}:: Another way to prevent unwanted page breaks. Definition Commands * Def Cmd Template:: Writing descriptions using definition commands. * Def Cmd Continuation Lines:: Continuing the heading over source lines. * Optional Arguments:: Handling optional and repeated arguments. * @code{@@deffnx}:: Group two or more `first' lines. * Def Cmds in Detail:: Reference for all the definition commands. * Def Cmd Conventions:: Conventions for writing definitions. * Sample Function Definition:: An example. The Definition Commands * Functions Commands:: Commands for functions and similar entities. * Variables Commands:: Commands for variables and similar entities. * Typed Functions:: Commands for functions in typed languages. * Typed Variables:: Commands for variables in typed languages. * Data Types:: The definition command for data types. * Abstract Objects:: Commands for object-oriented programming. Object-Oriented Programming * Variables: Object-Oriented Variables. * Methods: Object-Oriented Methods. Internationalization * @code{@@documentlanguage}:: Declaring the current language. * @code{@@documentencoding}:: Declaring the input encoding. Conditionally Visible Text * Conditional Commands:: Text for a given format. * Conditional Not Commands:: Text for any format other than a given one. * Raw Formatter Commands:: Using raw formatter commands. * Inline Conditionals:: Brace-delimited conditional text. * @code{@@set @@clear @@value}:: Variable tests and substitutions. * Testing for Texinfo Commands:: Testing if a Texinfo command is available. * Conditional Nesting:: Using conditionals inside conditionals. Flags: @code{@@set}, @code{@@clear}, conditionals, and @code{@@value} * @code{@@set @@value}:: Expand a flag variable to a string. * @code{@@ifset @@ifclear}:: Format a region if a flag is set. * @code{@@inlineifset @@inlineifclear}:: Brace-delimited flag conditionals. * @code{@@value} Example:: An easy way to update edition information. Defining New Texinfo Commands * Defining Macros:: Defining and undefining new commands. * Invoking Macros:: Using a macro, once you've defined it. * Macro Details:: Limitations of Texinfo macros. * @code{@@alias}:: Command aliases. * @code{@@definfoenclose}:: Customized highlighting. * External Macro Processors:: @code{#line} directives. External Macro Processors: Line Directives * @samp{#line} Directive:: * TeX: @samp{#line} and @TeX{}. * Syntax: @samp{#line} Syntax Details. Include Files * Using Include Files:: How to use the @code{@@include} command. * @code{texinfo-multiple-files-update}:: How to create and update nodes and menus when using included files. * Include Files Requirements:: @code{texinfo-multiple-files-update} needs. * Sample Include File:: A sample outer file with included files within it; and a sample included file. * Include Files Evolution:: How use of the @code{@@include} command has changed over time. Formatting and Printing Hardcopy * Use @TeX{}:: Use @TeX{} to format for hardcopy. * Format with @command{texi2dvi}:: The simplest way to format. * Format with @command{tex}/@command{texindex}:: Formatting with explicit shell commands. * Print with @command{lpr}:: How to print. * Within Emacs:: How to format and print from an Emacs shell. * Texinfo Mode Printing:: How to format and print in Texinfo mode. * Compile-Command:: How to print using Emacs's compile command. * Requirements Summary:: @TeX{} formatting requirements summary. * Preparing for @TeX{}:: What to do before you use @TeX{}. * Overfull hboxes:: What are and what to do with overfull hboxes. * @code{@@smallbook}:: How to print small format books and manuals. * A4 Paper:: How to print on A4 or A5 paper. * @code{@@pagesizes}:: How to print with customized page sizes. * Magnification:: How to print scaled up output. * PDF Output:: Portable Document Format output. * Obtaining @TeX{}:: How to obtain @TeX{}. Format with @command{tex}/@command{texindex} * Formatting Partial Documents:: * Details of @command{texindex}:: @command{texi2any}: The Generic Translator for Texinfo * Reference Implementation:: @command{texi2any}: the reference implementation. * Invoking @command{texi2any}:: Running the translator from a shell. * @command{texi2any} Environment Variables:: * @command{texi2any} Printed Output:: Calling @command{texi2dvi}. * Pointer Validation:: How to check that pointers point somewhere. * Customization Variables:: Configuring @command{texi2any}. * Internationalization of Document Strings:: Translating program-inserted text. * Invoking @command{pod2texi}:: Translating Perl pod to Texinfo. * @command{texi2html}:: An ancestor of @command{texi2any}. Customization Variables * Commands: Customization Variables for @@-Commands. * Options: Customization Variables and Options. * HTML: HTML Customization Variables. * Other: Other Customization Variables. Creating and Installing Info Files * Creating an Info File:: * Installing an Info File:: Creating an Info File * @command{makeinfo} Advantages:: @command{makeinfo} provides better error checking. * @code{makeinfo} in Emacs:: How to run @code{makeinfo} from Emacs. * @code{texinfo-format} commands:: Two Info formatting commands written in Emacs Lisp are an alternative to @code{makeinfo}. * Batch Formatting:: How to format for Info in Emacs batch mode. * Tag and Split Files:: How tagged and split files help Info to run better. Installing an Info File * Directory File:: The top level menu for all Info files. * New Info File:: Listing a new Info file. * Other Info Directories:: How to specify Info files that are located in other directories. * Installing Dir Entries:: How to specify what menu entry to add to the Info directory. * Invoking @command{install-info}:: @code{install-info} options. Generating HTML * HTML Translation:: Details of the HTML output. * HTML Splitting:: How HTML output is split. * HTML CSS:: Influencing HTML output with Cascading Style Sheets. * HTML Xref:: Cross-references in HTML output. HTML Cross-references * 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. htmlxref.cnf. Sample Texinfo Files * Short Sample Texinfo File:: * GNU Sample Texts:: * Verbatim Copying License:: * All-permissive Copying License:: Using Texinfo Mode * Texinfo Mode Overview:: How Texinfo mode can help you. * Emacs Editing:: Texinfo mode adds to GNU Emacs' general purpose editing features. * Inserting:: How to insert frequently used @@-commands. * Showing the Structure:: How to show the structure of a file. * Updating Nodes and Menus:: How to update or create new nodes and menus. * Info Formatting:: How to format for Info. * Printing:: How to format and print part or all of a file. * Texinfo Mode Summary:: Summary of all the Texinfo mode commands. Updating Nodes and Menus * Updating Commands:: Five major updating commands. * Updating Requirements:: How to structure a Texinfo file for using the updating command. * Other Updating Commands:: How to indent descriptions, insert missing nodes lines, and update nodes in sequence. Page Headings * Headings Introduced:: Conventions for using page headings. * Heading Format:: Standard page heading formats. * Heading Choice:: How to specify the type of page heading. * Custom Headings:: How to create your own headings and footings. Catching Mistakes * @command{makeinfo} Preferred:: @code{makeinfo} finds errors. * Debugging with Info:: How to catch errors with Info formatting. * Debugging with @TeX{}:: How to catch errors with @TeX{} formatting. * Using @code{texinfo-show-structure}:: How to use @code{texinfo-show-structure}. * Using @code{occur}:: How to list all lines containing a pattern. * Running @code{Info-validate}:: How to find badly referenced nodes. Finding Badly Referenced Nodes * Using @code{Info-validate}:: How to run @code{Info-validate}. * Unsplit:: How to create an unsplit file. * Tagifying:: How to tagify a file. * Splitting:: How to split a file manually. Info Format Specification * General: Info Format General Layout. * Text: Info Format Text Constructs. Info Format General Layout * Whole: Info Format Whole Manual. Split vs.@: nonsplit manuals. * 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. Info Format Text Constructs * Info Format Menu:: * Info Format Image:: * Info Format Printindex:: * Info Format Cross Reference:: @end detailmenu @end menu @c Reward readers for getting to the end of the menu :). @c Contributed by Arnold Robbins. @quotation Documentation is like sex: when it is good, it is very, very good; and when it is bad, it is better than nothing. ---Dick Brandon @end quotation @node Copying Conditions @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 @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 or PostScript format, including chapters, sections, cross-references, and indices. From the same Texinfo source file, you can create an HTML output file suitable for use with a web browser, you can create an Info file with special features to make browsing documentation easy, and also create a Docbook file or a transliteration to XML format. @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. You can edit a Texinfo file with any text editor, but it is especially convenient to use GNU Emacs since that editor 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, it provides almost no commands for controlling the final formatting. Texinfo is not intended to be a general-purpose formatting program, so if you need to lay out a newspaper, devise a glossy magazine ad, or follow the exact formatting requirements of a publishing house, Texinfo may not be the simplest tool. @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}. @menu * Reporting Bugs:: Submitting effective bug reports. * Output Formats:: Overview of the supported output formats. * Info Files:: What is an Info file? * Printed Books:: Characteristics of a printed book or manual. * Adding Output Formats:: Man pages and implementing new formats. * History:: Acknowledgements, contributors and genesis. @end menu @node Reporting Bugs @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. What's not critical is to ``narrow down'' the example to the smallest possible input---the actual input with which you discovered the bug will suffice. (Of course, if you do do experiments, the smaller the input file, the better.) @cindex Patches, contributing Patches are most welcome; if possible, please make them with @samp{@w{diff -c}} (@pxref{Top,,, diffutils, Comparing and Merging Files}) and include @file{ChangeLog} entries (@pxref{Change Log,,, emacs, The GNU Emacs Manual}), and follow the existing coding style. @node Output Formats @section Output Formats @cindex Output formats @cindex Back-end output formats Here is a brief overview of the output formats currently supported by Texinfo. @table @asis @item Info @cindex Info output, overview (Generated via @command{makeinfo}.) 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}. @item Plain text @cindex Plain text output, overview (Generated via @command{makeinfo --plaintext}.) This is almost the same as Info output with the navigational control characters are omitted. @item HTML @cindex HTML output, overview @cindex W3 consortium @cindex Mozilla @cindex Lynx @cindex Emacs-W3 (Generated via @command{makeinfo --html}.) HTML, standing for Hyper Text Markup Language, has become the most commonly used language for writing documents on the World Wide Web. Web browsers, 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{makeinfo} tries to use 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. For details of the HTML language and much related information, see @uref{http://www.w3.org/MarkUp/}. @xref{Generating HTML}. @item DVI @cindex DVI output, overview @pindex dvips @pindex xdvi (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}. (Be aware that the Texinfo language is very different from and much stricter than @TeX{}'s usual languages: plain @TeX{}, @LaTeX{}, Con@TeX{}t, etc.) @item PostScript @cindex PostScript output, overview (Generated via @command{texi2dvi --ps}.) PostScript is a page description language that became widely used around 1985 and is still used today. @uref{http://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}. @item PDF @cindex PDF output, overview @cindex Beebe, Nelson (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{http://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}. @item Docbook @cindex Docbook output, overview @cindex XML Docbook output, overview (Generated via @command{makeinfo --docbook}.) This is an XML-based format developed some years ago, 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. @item XML @cindex XML Texinfo output, overview @cindex Texinfo XML output, overview @cindex DTD, for Texinfo XML @pindex texinfo.dtd @pindex txixml2texi (Generated via @command{makeinfo --xml}.) XML is a generic syntax specification usable for any sort of content (a reference is at @uref{http://www.w3.org/XML}). The @command{makeinfo} XML output, unlike all the other output formats, is a transliteration of the Texinfo source rather than processed output. That is, it translates the Texinfo markup commands into XML syntax, for further processing by XML tools. The XML contains enough information to recreate the original content, except for syntactic constructs such as Texinfo macros and conditionals. The Texinfo source distribution includes a utility script @file{txixml2texi} to do that backward transformation. The details of the output syntax are defined in an XML DTD as usual, which is contained in a file @file{texinfo.dtd} included in the Texinfo source distribution and available via the Texinfo web pages. Texinfo XML files, and XML files in general, cannot be viewed in typical web browsers; they won't follow the DTD reference and as a result will simply report a (misleading) syntax error. @end table @node Info Files @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{makeinfo}, also known as @command{texi2any}, 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 @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. 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 a general purpose typesetting program. Texinfo provides a file @file{texinfo.tex} that contains information (definitions or @dfn{macros}) that @TeX{} uses when it typesets a Texinfo file. (@file{texinfo.tex} tells @TeX{} how to convert the Texinfo @@-commands to @TeX{} commands, which @TeX{} can then process to create the typeset document.) @file{texinfo.tex} contains the specifications for printing a document. You can get the latest version of @file{texinfo.tex} from the Texinfo home page, @uref{http://www.gnu.org/software/texinfo/}. In the United States, documents are most often printed on 8.5 inch by 11 inch pages (216@dmn{mm} by 280@dmn{mm}); this is the default size. But you can also print for 7 inch by 9.25 inch pages (178@dmn{mm} by 235@dmn{mm}, the @code{@@smallbook} size; or on A4 or A5 size paper (@code{@@afourpaper}, @code{@@afivepaper}). @xref{@code{@@smallbook}}, and @ref{A4 Paper}. @cindex Literate programming @TeX{} is freely distributable. It is written in a superset of Pascal for literate programming called WEB and can be compiled either in Pascal or (by using a conversion program that comes with the @TeX{} distribution) in C. @TeX{} is very powerful and has a great many features. 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{Obtaining @TeX{}}, for information on acquiring @TeX{}. It is not part of the Texinfo distribution. @node Adding Output 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. @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 @section History @cindex Stallman, Richard M. @cindex Chassell, Robert J. @cindex Fox, Brian @cindex Berry, Karl 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, and originally wrote the standalone @command{makeinfo} and @command{info} programs. Karl Berry has continued maintenance since Texinfo 3.8 (manual edition 2.22). @cindex Pinard, Fran@,{c}ois @cindex Schwab, Andreas @cindex Weinberg, Zack @cindex Weisshaus, Melissa @cindex Zaretskii, Eli @cindex Zuhn, David D. Our thanks go out to all who helped improve this work, particularly the indefatigable Eli Zaretskii and Andreas Schwab, who have provided patches beyond counting. Fran@,{c}ois Pinard and David@tie{}D. Zuhn, tirelessly recorded and reported mistakes and obscurities. Zack Weinberg did the impossible by implementing the macro syntax in @file{texinfo.tex}. Thanks to Melissa Weisshaus for her frequent reviews of nearly similar editions. Dozens of others have contributed patches and suggestions, they are gratefully acknowledged in the @file{ChangeLog} file. Our mistakes are our own. @cindex History of Texinfo @cindex Texinfo history @subheading Beginnings @cindex Scribe @cindex Reid, Brian 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, not too dissimilar format called Bolio. This then was converted to using @TeX{} as its typesetting language: 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. Richard Stallman (RMS) worked on both Bolio and Bo@TeX{}. He also developed a nifty on-line help format called Info, and then 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. Moving forward, 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}. @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. That implementation, however, was abandoned in favor of the current program, which parses the Texinfo input into a tree for processing. It still supports nearly all the features of @command{texi2html}. The new Perl program is much slower than the old C program. We hope the speed gap will close in the future, 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. Although of course it's perfectly plausible to write such support in C, in the particular case of @command{makeinfo}, it would have been tantamount to rewriting the entire program. In Perl, much of that comes essentially for free. @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, our Perl 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{}), and they will now be much more feasible to implement. Which leads to the last item: @item Making contributions easier. In general, due to the cleaner structure, the Perl program should be considerably easier than the C for anyone to read and contribute to, with the resulting obvious benefits. @end itemize @xref{Reference Implementation}, for more on the rationale for and role of @command{texi2any}. @node Writing a Texinfo 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. @menu * Conventions:: General rules for writing a Texinfo file. * Comments:: Writing comments and ignored text in general. * Minimum:: What a Texinfo file must have. * Short Sample:: A short sample Texinfo file. @end menu @node Conventions @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 @@-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@footnote{The word @dfn{argument} comes from the way it is used in mathematics and does not refer to a dispute between two people; it refers to the information presented to the command. According to the @cite{Oxford English Dictionary}, the word derives from the Latin for @dfn{to make clear, prove}; thus it came to mean `the evidence offered as proof', which is to say, `the information offered', which led to its mathematical meaning. In its other thread of derivation, the word came to mean `to assert in a manner against which others may make counter assertions', which led to the meaning of `argument' as a dispute.} 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 @cindex Form feed characters @cindex @kbd{CTRL-l} Form feed (@kbd{CTRL-l}) characters in the input are handled as follows: @table @asis @item PDF/DVI In normal text, treated as ending any open paragraph; essentially ignored between paragraphs. @item Info Output as-is between paragraphs (their most common use); 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. @item @cindex Tabs; don't use! @strong{Caution:} Last, do not use tab characters in a Texinfo file! (Except perhaps in verbatim modes.) @TeX{} uses variable-width fonts, which means that it is impractical at best to define a tab to work in all circumstances. Consequently, @TeX{} treats tabs like single spaces, and that is not what they look like in the source. Furthermore, @code{makeinfo} does nothing special with tabs, and thus a tab character in your input file will usually have a different appearance in the output. @noindent 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 itemize @node Comments @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. @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 @section What a Texinfo File Must Have @cindex Minimal Texinfo file (requirements) @cindex Must have in Texinfo file @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}. In order to be made into a printed manual and other output formats, a Texinfo file must begin with lines like this: @example @group \input texinfo @@settitle @var{name-of-manual} @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)} @noindent Here's an explanation: @itemize @bullet @item 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{}.) @item 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@. Strictly speaking, @code{@@settitle} is optional---if you don't mind your document being titled `Untitled'. @item The @code{@@bye} line at the end of the file on a line of its own tells the formatters 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. @end itemize Furthermore, you will usually provide a Texinfo file with 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 two lines at the beginning and the one line at the end. @node Short Sample @section A Short Sample Texinfo File @cindex Sample Texinfo file, with comments Here is a short but complete Texinfo file, so you can see how Texinfo source appears in practice. The first three parts of the file are mostly boilerplate: when writing a manual, you simply change the names as appropriate. The complete file, without interspersed comments, is shown in @ref{Short Sample Texinfo File}. @xref{Beginning and Ending a File}, for more documentation on the commands listed here. @subheading Header @noindent The header tells @TeX{} which definitions file to use, names the manual, and carries out other such housekeeping tasks. @example @group \input texinfo @@settitle Sample Manual 1.0 @end group @end example @subheading Summary Description and Copyright This segment describes the document and contains the copyright notice and copying permissions. This is done with the @code{@@copying} command. @noindent A real manual includes more text here, according to the license under which it is distributed. @xref{GNU Sample Texts}. @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 @subheading Titlepage, Copyright, Contents The title and copyright segment contains the title and copyright pages for the printed manual. The segment must be enclosed between @code{@@titlepage} and @code{@@end titlepage} commands. The title and copyright page does not appear in the online output. @noindent We use the @code{@@insertcopying} command to include the permission text from the previous section, instead of writing it out again; it is output on the back of the title page. The @code{@@contents} command generates a table of contents. @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 @@c Output the table of contents at the beginning. @@contents @end example @subheading `Top' Node and Master Menu The `Top' node starts off the online output; it does not appear in the printed manual. 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 @samp{@@top} command itself helps @command{makeinfo} determine the relationships between nodes. The `Top' node contains at least a top-level @dfn{menu} listing the chapters, and possibly a @dfn{Master Menu} listing all the nodes in the entire document. @example @@ifnottex @@node Top @@top Short Sample This is a short sample Texinfo file. @@end ifnottex @group @@menu * First Chapter:: The first chapter is the only chapter in this sample. * Index:: Complete index. @@end menu @end group @end example @subheading The Body of the Document @noindent The body segment contains all the text of the document, but not the indices or table of contents. This example illustrates a node and a chapter containing an enumerated list. @example @group @@node First Chapter @@chapter First Chapter @@cindex chapter, first @end group @group This is the first chapter. @@cindex index entry, another @end group @group Here is a numbered list. @@enumerate @@item This is the first item. @@item This is the second item. @@end enumerate @end group @end example @subheading The End of the Document This may contain commands for printing indices, and closes with the @code{@@bye} command, which marks the end of the document. @example @group @@node Index @@unnumbered Index @end group @group @@printindex cp @@bye @end group @end example @subheading Some Results Here is what the contents of the first chapter of the sample look like: @sp 1 @need 700 @quotation 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 @end quotation @node Beginning and Ending a File @anchor{Beginning a File} @c old name @chapter Beginning and Ending a Texinfo File @cindex Beginning a Texinfo file @cindex Texinfo file beginning @cindex File beginning This chapter expands on the minimal complete Texinfo source file previously given (@pxref{Short Sample}). Certain pieces of information must be provided at the beginning of a Texinfo file, such as the title of the document and the Top node. A table of contents is also generally produced here. @cindex Frontmatter, text in Straight text outside of any command before the Top node should be avoided. Such text is treated differently in the different output formats: at the time of writing, it is visible in @TeX{} and HTML, by default not shown in Info readers, and so on. @menu * Sample Beginning:: A sample beginning for a Texinfo file. * Texinfo File Header:: The first lines. * Document Permissions:: Ensuring your manual is free. * Titlepage & Copyright Page:: Creating the title and copyright pages. * Contents:: How to create a table of contents. * The Top Node:: Creating the `Top' node and master menu. * Global Document Commands:: Affecting formatting throughout. * Ending a File:: What is at the end of a Texinfo file? @end menu @node Sample Beginning @section Sample Texinfo File Beginning @cindex Example beginning of Texinfo file The following sample shows what is needed. The elements given here are explained in more detail in the following sections. Other commands are often included at the beginning of Texinfo files, but the ones here are the most critical. @xref{GNU Sample Texts}, for the full texts to be used in GNU manuals. @example \input texinfo @@settitle @var{name-of-manual} @var{version} @@copying This manual is for @var{program}, version @var{version}. Copyright @@copyright@{@} @var{years} @var{copyright-owner}. @group @@quotation Permission is granted to @dots{} @@end quotation @@end copying @end group @group @@titlepage @@title @var{name-of-manual-when-printed} @@subtitle @var{subtitle-if-any} @@subtitle @var{second-subtitle} @@author @var{author} @end group @group @@c The following two commands @@c start the copyright page. @@page @@vskip 0pt plus 1filll @@insertcopying @end group Published by @dots{} @@end titlepage @@c So the toc is printed at the start. @@contents @@ifnottex @@node Top @@top @var{title} This manual is for @var{program}, version @var{version}. @@end ifnottex @group @@menu * First Chapter:: Getting started @dots{} * Second Chapter:: @dots{} @dots{} * Copying:: Your rights and freedoms. @@end menu @end group @group @@node First Chapter @@chapter First Chapter @@cindex first chapter @@cindex chapter, first @dots{} @end group @end example @node Texinfo File Header @section Texinfo File Header @cindex Header for Texinfo files @cindex Texinfo file header Texinfo files start with at least two lines. These are the @code{\input texinfo} line and the @code{@@settitle} line. Also, if you want to format just part of the Texinfo file in Emacs, you must write the @code{@@settitle} line between start-of-header and end-of-header lines. These start- and end-of-header lines are optional, but they do no harm, so you might as well always include them. Any command that affects document formatting as a whole makes sense to include in the header. @code{@@synindex} (@pxref{@code{@@synindex}}), for instance, is another command often included in the header. Thus, the beginning of a Texinfo file looks approximately like this: @example @group \input texinfo @@settitle Sample Manual 1.0 @end group @end example (@xref{GNU Sample Texts} for complete sample texts.) @menu * First Line:: The first line of a Texinfo file. * Start of Header:: Formatting a region requires this. * @code{@@setfilename}:: Tell Info the name of the Info file. * @code{@@settitle}:: Create a title for the printed work. * End of Header:: Formatting a region requires this. @end menu @node First Line @subsection 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 Start of Header @subsection Start of Header @cindex Start of header line 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 line with an @code{@@settitle} line and, optionally, with other commands that globally affect the document formatting, such as @code{@@synindex} or @code{@@footnotestyle}; and then by an end-of-header line (@pxref{End of Header}). The start- and end-of-header lines allow you to format only part of a Texinfo file for Info or printing. @xref{@code{texinfo-format} commands}. 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}. @node @code{@@setfilename} @subsection @code{@@setfilename}: Set the Output File Name @anchor{setfilename}@c old name @findex setfilename @cindex Texinfo requires @code{@@setfilename} @cindex Output file name, required The @code{@@setfilename} line specifies the name of the output file to be generated. 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. @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, @code{makeinfo} uses the input file name to determine the output name: first, any of the extensions @code{.texi}, @code{.tex}, @code{.txi} or @code{.texinfo} is removed from the input file name; then, the output format specific extension is added---@code{.html} when generating HTML, @code{.info} when generating Info, etc. The @code{\input} line is still ignored in this processing, as well as leading blank lines. When producing another output format, @code{makeinfo} 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. @code{@@setfilename} used to be required by the Texinfo processors, and some other programs may still expect it to be present; for example, Automake (@pxref{Texinfo,,,automake, GNU Automake}). @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 is @file{texinfo} rather than @file{texinfo.info}. When @code{makeinfo} is running on operating systems such as MS-DOS which impose severe limits on file names, it may remove some characters from the original file name to leave enough space for the subfile suffix, thus producing files named @file{texin-10}, @file{gcc.i12}, etc. See also the @option{--output} option in @ref{Invoking @command{texi2any}}. @node @code{@@settitle} @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 (described in the previous section). This command tells @TeX{} the title to use in a header or footer for double-sided output, in case such headings are output. For more on headings for @TeX{}, see @ref{Heading Generation}. @cindex @code{} HTML tag @noindent then the Docbook output uses corresponding special tags (@code{}, etc.)@: instead of the default @code{ }. HTML output always uses @code{}. 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 @findex smallquotation Texinfo also provides a command @code{@@smallquotation}, which is just like @code{@@quotation} but uses a smaller font size where possible. @xref{@code{@@small@dots{}}}. @node @code{@@indentedblock} @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 @findex smallindentedblock Texinfo also provides a command @code{@@smallindentedblock}, which is just like @code{@@indentedblock} but uses a smaller font size where possible. @xref{@code{@@small@dots{}}}. @node @code{@@example} @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 an example that is not part of the running text, such as computer input or output. Write an @code{@@example} command at the beginning of a line by itself. Mark the end of the example with an @code{@@end example} command, also written at the beginning of a line by itself. An @code{@@example} environment has the following characteristics: @itemize @item Each line in the input file is a line in the output; that is, the source text is not filled as it normally is. @item Extra spaces and blank lines are significant. @item The output is indented. @item The output uses a fixed-width font. @item Texinfo commands @emph{are} expanded; if you want the output to be the input verbatim, use the @code{@@verbatim} environment instead (@pxref{@code{@@verbatim}}). @end itemize 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 lines containing @code{@@example} and @code{@@end example} will disappear from the output. To make the output look good, you should put a blank line before the @code{@@example} and another blank line after the @code{@@end example}. Blank lines inside the beginning @code{@@example} and the ending @code{@@end example}, on the other hand, do appear in the output. @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. In Emacs, you can use @kbd{M-x untabify} to convert tabs in a region to multiple spaces. @end quotation 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 want to embed code fragments within sentences, instead of displaying them, use the @code{@@code} command or its relatives (@pxref{@code{@@code}}). If you wish to write a ``comment'' on a line of an example in the normal roman font, you can use the @code{@@r} command (@pxref{Fonts}). @node @code{@@verbatim} @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. In the printed manual, 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: @c oops, got to trick this a bit: can't use @end verbatim inside @verbatim @example @exdent @t{@@verbatim} @exdent @t{@{} @exdent @key{TAB}@t{@@command with strange characters: @@'e} @exdent @t{expand@key{TAB}me} @exdent @t{@}} @exdent @t{@@end verbatim} @end example @noindent 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: @c more cheating ... @smallexample @exdent @t{@@smallformat} @exdent @t{@@verbatim} @exdent @t{... still verbatim, but in a smaller font ...} @exdent @t{@@end verbatim} @exdent @t{@@end smallformat} @end smallexample 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} @section @code{@@lisp}: Marking a Lisp Example @anchor{lisp}@c old name @findex lisp @cindex Lisp example The @code{@@lisp} command is used for Lisp code. It is synonymous with the @code{@@example} command. @lisp This is an example of text written between an @code{@@lisp} command and an @code{@@end lisp} command. @end lisp Use @code{@@lisp} instead of @code{@@example} 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. Mark the end of @code{@@lisp} with @code{@@end lisp} on a line by itself. @node @code{@@display} @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 @findex smalldisplay Texinfo also provides the environment @code{@@smalldisplay}, which is like @code{@@display} but uses a smaller font size. @xref{@code{@@small@dots{}}}. @node @code{@@format} @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. @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 @findex smallformat Texinfo also provides the environment @code{@@smallformat}, which is like @code{@@format} but uses a smaller font size. @xref{@code{@@small@dots{}}}. @node @code{@@exdent} @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. In a printed manual, the text on an @code{@@exdent} line is printed in the roman font. @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} has no effect in HTML output. @node @code{@@flushleft @@flushright} @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} @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 has no effect in Info and HTML output, where text is always set ragged right. 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} @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} @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} @section @code{@@cartouche}: Rounded Rectangles @anchor{cartouche}@c old name @findex cartouche @cindex Box with rounded corners @cindex Rounded rectangles, around text In a printed manual, the @code{@@cartouche} command draws a box with rounded corners around its contents. In HTML, a normal rectangle is drawn. @code{@@cartouche} has no effect in Info output. You can use this command to further highlight an example or quotation. 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} also implies @code{@@group} (@pxref{@code{@@group}}). @node @code{@@small@dots{}} @section @code{@@small@dots{}} Block Commands @anchor{small}@c old name @findex smallexample @findex smallformat @findex smalllisp @findex smallquotation @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 Info and HTML output, the @code{@@small@dots{}} commands are equivalent to their non-small companion commands. In @TeX{}, 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. A smaller font size is also retained in the Texinfo@tie{}XML transliteration. 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 Info, 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, a printed document looks better if you use only one of (for instance) @code{@@example} or @code{@@smallexample} consistently within a chapter. @node 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. @menu * Introducing Lists:: Texinfo formats lists for you. * @code{@@itemize}:: How to construct a simple list. * @code{@@enumerate}:: How to construct a numbered list. * Two-column Tables:: How to construct a two-column table. * Multi-column Tables:: How to construct generalized tables. @end menu @node Introducing Lists @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. @findex end 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} @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 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{makeinfo} 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} @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 brief summary of the alternatives. The summary is constructed using @code{@@enumerate} with an argument of @kbd{a}. @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 @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. @menu * @code{@@table}:: How to construct a two-column table. * @code{@@ftable @@vtable}:: Automatic indexing for two-column tables. * @code{@@itemx}:: How to put more entries in the first column. @end menu @node @code{@@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 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 before an @code{@@item} line (except the first one). This puts a blank line in the Info file. Except when the entries are very brief, a blank line looks better. End the table with a line consisting of @code{@@end table}, followed by a blank line. @TeX{} will always start a new paragraph after the table, so the blank line is needed for the Info output to be analogous. @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} @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} @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. 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 @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. @menu * Multitable Column Widths:: Defining multitable column widths. * Multitable Rows:: Defining multitable rows, with examples. @end menu @node 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. @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. @end enumerate @node Multitable Rows @subsection Multitable Rows @cindex Multitable rows @cindex Rows, of a multitable @findex item @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{} HTML/XML 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{} 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 @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. @menu * Floats:: Figures, tables, and the like. * Images:: Including graphics and images. * Footnotes:: Writing footnotes. @end menu @node Floats @section Floats @cindex Floats, in general 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 the present version of Texinfo, 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}}). @menu * @code{@@float}:: Producing floating material. * @code{@@caption @@shortcaption}:: Specifying descriptions for floats. * @code{@@listoffloats}:: A table of contents for floats. @end menu @node @code{@@float} @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 @code{@@listoffloats} output (@pxref{@code{@@listoffloats}}). Cross references to @var{label} are allowed. @cindex Floats, 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. @cindex Floats, 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} @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}) or other complex constructs. The same constraints apply to @code{@@caption} unless there is a @code{@@shortcaption}. @node @code{@@listoffloats} @subsection @code{@@listoffloats}: Tables of Contents for Floats @anchor{listoffloats}@c old name @findex listoffloats @cindex List of floats @cindex Floats, 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 And here's what the output from @code{@@listoffloats} looks like, given the example figure earlier in this chapter (the Info output is formatted as a menu): @display @ifinfo * Figure 12.1: fig:ex1. @end ifinfo @ifnotinfo @listoffloats Figure @end ifnotinfo @end display 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}}). 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. In Info, the result is a menu where each float can be selected. In HTML, each line is a link to the float. In printed output, the page number is included. Unnumbered floats (those without cross-reference labels) are omitted from the list of floats. @node Images @section Inserting Images @cindex Images, inserting @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. @menu * Image Syntax:: * Image Scaling:: @end menu @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 pdf@TeX{} 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 For Info, @code{makeinfo} includes @file{@var{filename}.txt} 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 For HTML, @code{makeinfo} outputs a reference to @file{@var{filename}.png}, @file{@var{filename}.jpg}, @file{@var{filename}.jpeg} or @file{@var{filename}.gif} (in that order). 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 For Docbook, @code{makeinfo} outputs 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}, 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 Info and HTML output, @code{makeinfo} uses the optional fifth argument @var{extension} to @code{@@image} for the filename 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. For @TeX{} output, if an image is the only thing in a paragraph it will ordinarily be displayed on a line by itself, respecting the current environment indentation, but without the normal paragraph indentation. If you want it centered, use @code{@@center} (@pxref{@code{@@titlefont @@center @@sp}}). @cindex Alt attribute for images @cindex Images, alternate text for @findex @sortas{-} -@r{ (in image alt string)} For HTML output, @code{makeinfo} sets the @dfn{alt attribute} for inline images to the optional @var{alttext} (fourth) argument to @code{@@image}, if supplied. If not supplied, @code{makeinfo} uses the full file name of the image being displayed. 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 @code{alt} 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, @code{makeinfo} writes a reference to the binary image file (trying @var{filename} suffixed with @file{@var{extension}}, @file{@var{.extension}}, @file{.png}, or @file{.jpg}, in that order) if one exists. It also literally includes the @file{.txt} file 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. @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. @node Image Scaling @subsection Image Scaling @cindex Images, 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 @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 @TeX{}, not in HTML or any other sort of output. @node 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. @menu * Footnote Commands:: How to write a footnote in Texinfo. * Footnote Styles:: Controlling how footnotes appear in Info. @end menu @node Footnote Commands @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 a printed manual or book, 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 @subsection Footnote Styles Info has two footnote styles, which determine where the text of the footnote is located: @itemize @bullet @cindex @samp{@r{End}} node footnote style @item In the `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 @cindex @samp{@r{Separate}} footnote style @item In the `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: @smallexample @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 smallexample @end itemize 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 an Info file's 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 before or shortly after the end-of-header line at the beginning of a Texinfo file. (You should include any @code{@@footnotestyle} command between the start-of-header and end-of-header lines, so the region formatting commands will format footnotes as specified.) 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. @node 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 an Info file, this information is a menu entry leading to the first node referenced. 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. @menu * Predefined Indices:: Use different indices for different kinds of entries. * Indexing Commands:: How to make an index entry. * Advanced Indexing:: Advanced indexing commands. * Index Entries:: Choose different words for index entries. * Printing Indices & Menus:: How to print an index in hardcopy and generate index menus in Info. * Combining Indices:: How to combine indices. * New Indices:: How to define your own indices. @end menu @node Predefined Indices @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 (@code{@@cindex}) Concept index, for general concepts. @item fn @cindex @code{fn} (function) index @findex findex (@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 (@code{@@kindex}) Keystroke index, for keyboard commands. @item pg @cindex @code{pg} (program) index @findex pindex (@code{@@pindex}) Program index, for names of programs. @item tp @cindex @code{tp} (data type) index @findex tindex (@code{@@tindex}) Data type index, for type names (such as structures defined in header files). @item vr @cindex @code{vr} (variable) index @findex vindex (@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}). @node Indexing Commands @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. 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 small roman font and entries for the other indices are printed in a small @code{@@code} 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 For the printed output, 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 To reduce the quantity of sort keys you need to provide explicitly, 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'. @node Advanced Indexing @section Advanced Indexing Commands @cindex Indexing, advanced @cindex Advanced indexing Texinfo provides several commands for doing advanced indexing, similar to the indices you may see in professionally published books. @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 villians @@cindex Superhumans @@subentry heros @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 betwen 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. These features are most useful with printed documents created with @TeX{}, and when translating Texinfo to Docbook. @node 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 @section Printing Indices and Menus @cindex Printing an index @cindex Indices, printing and menus @cindex Generating menus with indices @cindex Menus generated with indices To print an index means to include it as part of a manual or Info file. 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. To generate an index, you must include the @code{@@printindex} command at the place in the document where you want the index to appear. Also, as part of the process of creating a printed manual, you must run a program called @code{texindex} (@pxref{Hardcopy}) to sort the raw data to produce a sorted index file. The sorted index file is what is actually used to print the index. Texinfo offers six separate types of predefined index, which suffice in most cases. See the other parts of this chapter for information on this, as well as advanced indexing commands, defining your own new indices, combining indices, and, most importantly, advice on writing the actual index entries. This section focuses on printing indices, which is done with the @code{@@printindex} command. @findex printindex @code{@@printindex} takes one argument, a two-letter index abbreviation. It reads the corresponding sorted index file (for printed output), and formats it appropriately into an index. The @code{@@printindex} command does not generate a chapter heading for the index, since different manuals have different needs. Consequently, 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: @smallexample @group @@node Variable Index @@unnumbered Variable Index @@printindex vr @end group @group @@node Concept Index @@unnumbered Concept Index @@printindex cp @end group @end smallexample If you have more than one index, we recommend placing the concept index last. @itemize @item In printed output, @code{@@printindex} produces a traditional two-column index, with dot leaders between the 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: @smallexample * First index entry: Top. (line 7) @end smallexample @noindent The actual number of spaces is variable, to right-justify the line number; it's been reduced here to make the line fit in the printed manual. @item In plain text output, @code{@@printindex} produces the same menu, but the line numbers are relative to the start of the file, since that's more convenient for that format. @item In HTML output, @code{@@printindex} produces links to the index entries. @item In XML and Docbook output, it simply records the index to be printed. @end itemize @node Combining 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}. @menu * @code{@@syncodeindex}:: How to merge two indices, using @code{@@code} font for the merged-from index. * @code{@@synindex}:: How to merge two indices, using the roman font for the merged-from index. @end menu @node @code{@@syncodeindex} @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 variables 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} @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 @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 however 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{makeinfo} already reports an error if a new index conflicts well-known extension name. @node Insertions @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. @iftex These are: @itemize @bullet @item The Texinfo special characters: @samp{@@ @{@} , \ # &}. @item Whitespace within and around a sentence. @item Accents. @item Dots and bullets. @item The @TeX{} logo and the copyright symbol. @item The euro and pounds currency symbols. @item The degrees symbol. @item The minus sign. @item Mathematical expressions. @item Glyphs for examples of programming: evaluation, macros, errors, etc. @item Footnotes. @end itemize @end iftex @menu * Special Characters:: Inserting @@ @{@} , \ # & * Inserting Quote Characters:: Inserting left and right quotes, in code. * Inserting Space:: Inserting the right amount of whitespace. * Inserting Accents:: Inserting accents and special characters. * Inserting Quotation Marks:: Inserting quotation marks. * Inserting Subscripts and Superscripts:: Inserting sub/superscripts. * Inserting Math:: Formatting mathematical expressions. * Glyphs for Text:: Inserting dots, bullets, currencies, etc. * Glyphs for Programming:: Indicating results of evaluation, expansion of macros, errors, etc. * Inserting Unicode:: Inserting a Unicode character by code point. @end menu @node Special Characters @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. @menu * Inserting an Atsign:: @code{@@@@}, @code{@@atchar@{@}}. * Inserting Braces:: @code{@@@{ @@@}}, @code{@@l rbracechar@{@}}. * Inserting a Comma:: , and @code{@@comma@{@}}. * Inserting a Backslash:: \ and @code{@@backslashchar@{@}}. * Inserting a Hashsign:: # and @code{@@hashchar@{@}}. * Inserting an Ampersand:: & and @code{@@ampchar@{@}}. @end menu @node Inserting an Atsign @subsection Inserting `@@' with @code{@@@@} and @code{@@atchar@{@}} @cindex At sign, inserting @cindex Inserting @@ @r{(literal @samp{@@})} @findex @sortas{@@} @@ @r{(literal @samp{@@})} @findex atchar@{@} @r{(literal @samp{@@})} @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 @subsection Inserting `@{ `@}' with @code{@@@{ @@@}} and @code{@@l rbracechar@{@}} @findex @{ @r{(literal @samp{@{})} @findex @} @r{(literal @samp{@}})} @findex lbracechar@{@} @r{(literal @samp{@{})} @findex rbracechar@{@} @r{(literal @samp{@}})} @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 @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{@@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 @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 Texinfo documents may also use \ as a command character inside @code{@@math} (@pxref{Inserting Math}). In this case, @code{@@\} or @code{\backslash} produces 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 @subsection Inserting `#' with @code{@@hashchar@{@}} @findex hashchar@{@} @r{(literal @samp{#})} @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 @subsection Inserting `&' with @code{@@&} and @code{@@ampchar@{@}} @findex ampchar@{@} @r{(literal @samp{&})} @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 has a special meaning in Texinfo in just one restricted context. In the argument to a definition command (@pxref{Definition Commands}), Emacs Lisp keywords beginning with ampersands are recognized and typeset specially. @xref{A Sample Function Description,,, elisp, GNU Emacs Lisp Reference Manual}. For example: @example @@defun foo integer1 &optional integer2 &rest integers @@code@{foo@} described here. @@end defun @end example @noindent leads to the output @defun foo integer1 &optional integer2 &rest integers @code{foo} described here. @end defun So, in order to typeset an ampersand in such a context (for example, in documentation of a C++ function taking a reference as a parameter), it's necessary to use @code{@@&} or some other construct. Here's an example: @example @@deftypefn Function int foo (@@code@{const std::vector@@&@} bar) Documentation of @@code@{foo@}. @@end deftypefn @end example @noindent This gives the output @deftypefn Function int foo (@code{const std::vector @&} 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 @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{}. This works all right for text. However, in examples of computer code, readers are especially likely to cut and paste the text verbatim---and, unfortunately, some document viewers will mangle these characters. (The free PDF reader @command{xpdf} works fine, but other PDF readers, both free and nonfree, have problems.) If this is a concern for you, Texinfo provides these two commands: @table @code @item @@codequoteundirected @var{on-off} @findex codequoteundirected @cindex undirected single quote causes the output for the @code{'} character in code environments to be the undirected single quote, like this: @set txicodequoteundirected on @code{'}. @set txicodequoteundirected off @item @@codequotebacktick @var{on-off} @findex codequotebacktick @cindex backtick @cindex grave accent, standalone causes the output for the @code{`} character in code environments to be the backtick character (standalone grave accent), like this: @set txicodequotebacktick on @code{`}. @set txicodequotebacktick off @end table If you want these settings for only part of the document, @code{@@codequote... off} will restore the normal behavior, as in @code{@@codequoteundirected off}. These settings affect @code{@@code}, @code{@@example}, @code{@@kbd}, @code{@@samp}, @code{@@verb}, and @code{@@verbatim}. @xref{Useful Highlighting}. @vindex txicodequoteundirected@r{, obsolete variable} @vindex txicodequotebacktick@r{, obsolete variable} This feature used to be controlled by using @code{@@set} to change the values of the corresponding variables @code{txicodequoteundirected} and @code{txicodequotebacktick}; they are still supported, but the command interface is preferred. @node Inserting Space @section Inserting Space @cindex Inserting space @cindex Spacing, inserting The following sections describe commands that control spacing of various kinds within and after sentences. @menu * Multiple Spaces:: Inserting multiple spaces. * Not Ending a Sentence:: Sometimes a . doesn't end a sentence. * Ending a Sentence:: Sometimes it does. * @code{@@frenchspacing}:: Specifying end-of-sentence spacing. * @code{@@dmn}:: Formatting a dimension. @end menu @node Multiple Spaces @subsection Multiple Spaces @cindex Multiple spaces @cindex Whitespace, inserting @cindex Space, inserting horizontal @findex @findex @findex 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 Other possible uses of @code{@@@kbd{SPACE}} have been subsumed by @code{@@multitable} (@pxref{Multi-column Tables}). Do not follow any of these commands with braces. To produce a non-breakable space, see @ref{@code{@@tie}}. @node Not Ending 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)} @findex : 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 sentences. @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 @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)} @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 the HTML output, @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} @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; for HTML, we don't try to override the browser). 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; for XML, it outputs a transliteration of itself (@pxref{Output Formats}). @node @code{@@dmn} @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 a little extra space in the printed output. That is, on seeing @code{@@dmn}, @TeX{} inserts just enough space for proper typesetting; 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 prevent @TeX{} from inserting extra whitespace, as shown here. @xref{Not Ending a Sentence}. @node Inserting Accents @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). To get the true accented characters output in Info, not just the ASCII transliterations, it is necessary to specify @code{@@documentencoding} with an encoding which supports the required characters (@pxref{@code{@@documentencoding}}). In this case, you can also use non-ASCII (e.g., pre-accented) characters in the source file. @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 @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 @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{}'}}. @TeX{} converts two single quotes to left- and right-hand doubled quotation marks, @c this comes out as "like this" in Info, which is just confusing. @iftex ``like this'', @end iftex and Info converts doubled single-quote characters to ASCII double-quotes: @w{@t{`@w{}`@dots{}'@w{}'}} becomes @w{@t{"@dots{}"}}. 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, 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 UTF-8 @cindex ISO 8859-15 @cindex Latin 9 @cindex ISO 8859-1 @cindex Latin 1 In order to get the symbols for the quotation marks in encoded Info output, it is necessary to specify @code{@@documentencoding UTF-8}. (@xref{@code{@@documentencoding}}.) Double guillemets are also present in ISO 8859-1 (aka Latin@tie{}1) and ISO 8859-15 (aka Latin@tie{}9). @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. @cindex Single quotation marks @cindex Double quotation marks @cindex Left quotation marks @cindex Right quotation marks @findex quotedblleft @cindex `@w{}` @findex quoteleft @cindex ` @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). Traditions for quotation mark usage vary to a great extent between languages (@url{http://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 counter-intuitive. Thus, in this case the following aliases would be convenient: @example @@alias lgqq = quotedblbase @@alias rgqq = quotedblleft @end example @node Inserting Subscripts and 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, in either text or math, with the @code{@@sub} and @code{@@sup} commands. (For other mathematical expressions, see the next section.) For example, here is a purely textual subscript and superscript: @example here@@sub@{below@}@@sup@{above@} @end example @noindent produces: @display here@sub{below}@sup{above} @end display @cindex Math italic font Inside @code{@@math}, @code{@@sub} and @code{@@sup} produce mathematical subscripts and superscripts. This uses a different font in the @TeX{} output (math italic instead of text italic); it makes no difference in the other output formats. Here's an example: @example @@math@{e@@sup@{x@}@} @end example @noindent produces: @display @math{e@sup{x}} @end display In Info and plain text, regardless of being used inside @code{@@math}, @code{@@sub@{@var{text}@}} is 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 (@TeX{} math, HTML), the superscript is set above the subscript when both commands are given consecutively. @node Inserting Math @section @code{@@math}: Inserting Mathematical Expressions @anchor{math}@c old name @findex math @cindex Mathematical expressions, inserting @cindex Formulas, mathematical You can write a short mathematical expression with the @code{@@math} command. Write the mathematical expression between braces, like this: @example @@math@{(a + b) = (b + a)@} @end example @iftex @noindent This produces the following in @TeX{}: @display @math{(a + b) = (b + a)} @end display @noindent and the following in other formats: @end iftex @ifnottex @noindent This produces the following in Info and HTML: @end ifnottex @example (a + b) = (b + a) @end example @cindex MathML, not used The @code{@@math} command has no special effect on the Info and HTML output. @command{makeinfo} expands any @@-commands as usual, but it does not try to use produce good mathematical formatting in any way (no use of MathML, etc.). The HTML output is enclosed by @code{...}, but nothing more. @findex \mathopsup However, as far as the @TeX{} output is concerned, plain @TeX{} mathematical commands are allowed in @code{@@math}, starting with @samp{\}. In essence, @code{@@math} switches into plain @TeX{} math mode. (Exception: the plain @TeX{} command @code{\sup}, which typesets the mathematical operator name `sup', must be accessed as @code{\mathopsup}, due to the conflict with Texinfo's @code{@@sup} command.) This allows you to use all the plain @TeX{} math control sequences for symbols, functions, and so on, and thus get proper formatting in the @TeX{} output, at least. The @code{@@sub} and @code{@@sup} commands described in the previous section produce subscripts and superscripts in HTML output as well as @TeX{}; the plain @TeX{} characters @code{_} and @code{^} for subscripts and superscripts are recognized by @TeX{} inside @code{@@math}, but do nothing special in HTML or other output formats. It's best to use @samp{\} instead of @samp{@@} for any such mathematical commands; otherwise, @command{makeinfo} will complain. On the other hand, @command{makeinfo} does allow input with matching (but unescaped) braces, such as @samp{k_@{75@}}; it complains about such bare braces in regular input. Here's an example: @example @@math@{\sin 2\pi \equiv \cos 3\pi@} @end example @iftex @noindent which looks like this in @TeX{}: @display @math{\sin 2\pi \equiv \cos 3\pi} @end display @noindent but @end iftex @noindent which looks like the input in Info and HTML: @example \sin 2\pi \equiv \cos 3\pi @end example @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}. @cindex Displayed equations @cindex Equations, displayed For displayed equations, you must at present use @TeX{} directly (@pxref{Raw Formatter Commands}). @node Glyphs for Text @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{makeinfo} is concerned, but @TeX{} is not so lucky. @menu * @code{@@TeX @@LaTeX}:: The @TeX{} logos. * @code{@@copyright}:: The copyright symbol (c in a circle). * @code{@@registeredsymbol}:: The registered symbol (R in a circle). * @code{@@dots}:: How to insert ellipses: @dots{} and @enddots{} * @code{@@bullet}:: How to insert a bullet: @bullet{} * @code{@@euro}:: How to insert the euro currency symbol. * @code{@@pounds}:: How to insert the pounds currency symbol. * @code{@@textdegree}:: How to insert the degrees symbol. * @code{@@minus}:: How to insert a minus sign. * @code{@@geq @@leq}:: How to insert greater/less-than-or-equal signs. @end menu @node @code{@@TeX @@LaTeX} @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 Info, 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 Info, the result is just @samp{LaTeX}. (@LaTeX{} is another macro package built on top of @TeX{}, very loosely analogous to Texinfo in that it emphasizes logical structure, but much (much) larger.) The spelling of these commands are unusual for Texinfo, in that they use both uppercase and lowercase letters. @node @code{@@copyright} @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; in Info, 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} @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; in Info, this is @samp{(R)}. @node @code{@@dots} @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 would work for the Info file output, but would produce the wrong amount of space between the periods in the printed manual. 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} @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. In Info, an asterisk is 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} @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. Texinfo cannot magically synthesize support for the Euro symbol where the underlying system (fonts, software, whatever) does not support it. Therefore, you may find it preferable to use the word ``Euro''. (In banking contexts, the abbreviation for the Euro is EUR@.) @cindex ISO 8859-15, and Euro @cindex Latin 9, and Euro In order to get the Euro symbol in encoded Info output, for example, it is necessary to specify @code{@@documentencoding ISO-8859-15} or @code{@@documentencoding UTF-8} (@xref{@code{@@documentencoding}}.) The Euro symbol is in ISO 8859-15 (aka Latin@tie{}9), and is @emph{not} in the more widely-used ISO 8859-1 (Latin@tie{}1). @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} @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} @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} @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. In a fixed-width font, this is a single hyphen, but in a proportional font, 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 @noindent In the fixed-width font used by Info, @code{@@minus@{@}} is the same as a hyphen. You should not use @code{@@minus@{@}} inside @code{@@code} or @code{@@example} because the width distinction is not made in the fixed-width font they use. When you use @code{@@minus} to specify the mark beginning each entry in an itemized list, you do not need to type the braces (@pxref{@code{@@itemize}}). If you actually want to typeset some math that does a subtraction, it is better to use @code{@@math}. Then the regular @samp{-} character produces a minus sign, as in @code{@@math@{a-b@}} (@pxref{Inserting Math}). @node @code{@@geq @@leq} @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 @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}, or by @code{@@lisp} and @code{@@end lisp}. 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. @menu * Glyphs Summary:: * @code{@@result}:: How to show the result of expression. * @code{@@expansion}:: How to indicate an expansion. * @code{@@print}:: How to indicate generated output. * @code{@@error}:: How to indicate an error message. * @code{@@equiv}:: How to indicate equivalence. * @code{@@point}:: How to indicate the location of point. * Click Sequences:: Inserting GUI usage sequences. @end menu @node Glyphs Summary @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} @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, @lisp (cdr '(1 2 3)) @result{} (2 3) @end lisp @noindent may be read as ``@code{(cdr '(1 2 3))} evaluates to @code{(2 3)}''. @node @code{@@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 @@lisp (third '(a b c)) @@expansion@{@} (car (cdr (cdr '(a b c)))) @@result@{@} c @@end lisp @end group @end example @noindent produces @lisp @group (third '(a b c)) @expansion{} (car (cdr (cdr '(a b c)))) @result{} c @end group @end lisp @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} @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. @lisp @group (progn (print 'foo) (print 'bar)) @print{} foo @print{} bar @result{} bar @end group @end lisp @noindent In a Texinfo source file, this example is written as follows: @lisp @group @@lisp (progn (print 'foo) (print 'bar)) @@print@{@} foo @@print@{@} bar @@result@{@} bar @@end lisp @end group @end lisp @node @code{@@error} @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 @@lisp (+ 23 'x) @@error@{@} Wrong type argument: integer-or-marker-p, x @@end lisp @end example @noindent produces @lisp (+ 23 'x) @error{} Wrong type argument: integer-or-marker-p, x @end lisp @noindent This indicates that the following error message is printed when you evaluate the expression: @lisp Wrong type argument: integer-or-marker-p, x @end lisp The word @samp{@error{}} itself is not part of the error message. @node @code{@@equiv} @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 @@lisp (make-sparse-keymap) @@equiv@{@} (list 'keymap) @@end lisp @end example @noindent produces @lisp (make-sparse-keymap) @equiv{} (list 'keymap) @end lisp @noindent This indicates that evaluating @code{(make-sparse-keymap)} produces identical results to evaluating @code{(list 'keymap)}. @node @code{@@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 @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 @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. (@xref{@code{@@documentencoding}}.) @cindex Entity reference in HTML et al. @cindex @samp{@var{hex};}, output from @code{@@U} In HTML, XML, and Docbook, the output from @code{@@U} is always an entity reference of the form @samp{@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 @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, 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 occur normally. You can use the break, break prevention, or pagination commands to fix problematic line and page breaks. @menu * Break Commands:: Summary of break-related commands. * Line Breaks:: Forcing line breaks. * @code{@@- @@hyphenation}:: Helping @TeX{} with hyphenation points. * @code{@@allowcodebreaks}:: Controlling line breaks within @@code text. * @code{@@w}:: Preventing unwanted line breaks in text. * @code{@@tie}:: Inserting an unbreakable but varying space. * @code{@@sp}:: Inserting blank lines. * @code{@@page}:: Forcing the start of a new page. * @code{@@group}:: Preventing unwanted page breaks. * @code{@@need}:: Another way to prevent unwanted page breaks. @end menu @node Break 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 @section @code{@@*} and @code{@@/}: Generate and Allow Line Breaks @findex * @r{(force line break)} @findex / @r{(allow line break)} @cindex Line breaks, 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 in the other output format. @node @code{@@- @@hyphenation} @section @code{@@-} and @code{@@hyphenation}: Helping @TeX{} Hyphenate @anchor{- and hyphenation}@c old name @findex @sortas{-} - @r{(discretionary hyphen)} @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 help @TeX{} out. Texinfo supports two commands for this: @table @code @item @@- Insert a discretionary hyphen, i.e., a place where @TeX{} can (but does not have to) hyphenate. This is especially useful when you notice 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}@} Tell @TeX{} how to hyphenate @var{hy-phen-a-ted words}. As shown, you put a @samp{-} at each hyphenation point. For example: @example @@hyphenation@{man-u-script man-u-scripts@} @end example @noindent @TeX{} only uses the specified hyphenation points when the words match exactly, so give all necessary variants, such as plurals. @end table Info, HTML, and other non-@TeX{} output is not hyphenated, so none of these commands have any effect there. @node @code{@@allowcodebreaks} @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 problems, 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 HTML and @TeX{} output. @node @code{@@w} @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 You can also use the @code{@@w} command to prevent @TeX{} from automatically hyphenating a long name or phrase that happens to fall near the end of a line. @command{makeinfo} does not ever hyphenate words. @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 in Info or plain text output, though. @node @code{@@tie} @section @code{@@tie@{@}}: Inserting an Unbreakable Space @anchor{tie}@c old name @findex tie @r{(unbreakable interword space)} @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} @section @code{@@sp} @var{n}: Insert Blank Lines @anchor{sp}@c old name @findex sp @r{(line spacing)} @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 in both the printed manual and the Info file. @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} @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} @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 (on a line by itself) is used inside an @code{@@example} or similar construct to begin an unsplittable vertical group, which will appear entirely on one page in the printed output. The group is terminated by a line containing only @code{@@end group}. These two lines produce no output of their own, and in the Info file output they have no effect at all. @c Once said that these environments @c turn off vertical spacing between ``paragraphs''. @c Also, quotation used to work, but doesn't in texinfo-2.72 Although @code{@@group} would make sense conceptually in a wide variety of contexts, its current implementation works reliably 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.) In other contexts, @code{@@group} can cause anomalous vertical spacing. @need 750 This formatting requirement means that you should write: @example @group @@example @@group @dots{} @@end group @@end example @end group @end example @noindent with the @code{@@group} and @code{@@end group} commands inside the @code{@@example} and @code{@@end example} commands. The @code{@@group} command is most often used to hold an example together on one page. In this Texinfo manual, more than 100 examples contain text that is enclosed between @code{@@group} and @code{@@end group}. If you forget to end a group, you may get strange and unfathomable error messages when you run @TeX{}. This is because @TeX{} keeps trying to put the rest of the Texinfo file onto the one page and does not start to generate error messages until it has processed considerable text. It is a good rule of thumb to look for a missing @code{@@end group} if you get incomprehensible error messages in @TeX{}. @node @code{@@need} @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 tells @TeX{} to start a new page 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 @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 such artifacts in a uniform format. In the Info file, a definition causes the entity category---`Function', `Variable', or whatever---to appear at the beginning of the first line of the definition, followed by the entity's name and arguments. In the printed manual, the command causes @TeX{} to print the entity's name and its arguments on the left margin and print the category next to the right margin. In both output formats, the body of the definition is indented. Also, the name of the entity is entered into the appropriate index: @code{@@deffn} enters the name into the index of functions, @code{@@defvr} enters it into the index of variables, and so on (@pxref{Predefined Indices}). 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. @menu * Def Cmd Template:: Writing descriptions using definition commands. * Def Cmd Continuation Lines:: Continuing the heading over source lines. * Optional Arguments:: Handling optional and repeated arguments. * @code{@@deffnx}:: Group two or more `first' lines. * Def Cmds in Detail:: Reference for all the definition commands. * Def Cmd Conventions:: Conventions for writing definitions. * Sample Function Definition:: An example. @end menu @node Def Cmd Template @section The Template for a Definition @cindex Definition template @cindex Template for a definition The @code{@@deffn} command is used for definitions of entities that resemble functions. To write a definition using the @code{@@deffn} command, 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. (You may embed examples in the body.) Finally, end the definition with an @code{@@end deffn} command written on a line of its own. The other definition commands follow the same format: a line with the @code{@@def@dots{}} command and whatever arguments are appropriate for that command; the body of the definition; and a corresponding @code{@@end} line. The template for a definition looks like this: @example @group @@deffn @var{category} @var{name} @var{arguments}@dots{} @var{body-of-definition} @@end deffn @end group @end example @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. Some of the definition commands are more general than others. The @code{@@deffn} command, for example, is the general definition command for functions and the like---for entities that may take arguments. When you use this command, you specify the category to which the entity belongs. Three predefined, specialized variations (@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. @xref{Sample Function Definition}, for a detailed example of a function definition, including the use of @code{@@example} inside the definition. @node Def Cmd Continuation 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 @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, conventionally specified by using 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 @code{@@defspec} 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 @noindent The function is listed in the Command and Variable Index under @samp{foobar}. @node @code{@@deffnx} @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}. The @code{@@deffnx} command works exactly like @code{@@deffn} except that it does not generate extra vertical white space between it and the preceding line. @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 @section The Definition Commands Texinfo provides more than a dozen definition commands, all of which are described in this section. The definition commands automatically enter the name of the entity in the appropriate index: for example, @code{@@deffn}, @code{@@defun}, and @code{@@defmac} enter function names in the index of functions; @code{@@defvr} and @code{@@defvar} enter variable names in the index of variables. Although the examples that follow mostly illustrate Lisp, the commands can be used for other programming languages. @menu * Functions Commands:: Commands for functions and similar entities. * Variables Commands:: Commands for variables and similar entities. * Typed Functions:: Commands for functions in typed languages. * Typed Variables:: Commands for variables in typed languages. * Data Types:: The definition command for data types. * Abstract Objects:: Commands for object-oriented programming. @end menu @node Functions Commands @subsection Functions and Similar Entities This section describes the commands for describing functions and similar entities: @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 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}. @code{@@deffn} prints argument names such as @var{nchars} in slanted type in the printed output, because we think of these names as metasyntactic variables---they stand for the actual argument values. Within the text of the description, however, 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. The template for @code{@@deffn} is: @example @group @@deffn @var{category} @var{name} @var{arguments}@dots{} @var{body-of-definition} @@end deffn @end group @end example @findex defun @item @@defun @var{name} @var{arguments}@dots{} The @code{@@defun} command is the definition command for functions. @code{@@defun} is equivalent to @samp{@@deffn Function @dots{}}. Terminate the definition with @code{@@end defun} on a line of its own. Thus, the template is: @example @group @@defun @var{function-name} @var{arguments}@dots{} @var{body-of-definition} @@end defun @end group @end example @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 Variables Commands @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. The template is: @example @group @@defvr @var{category} @var{name} @var{body-of-definition} @@end defvr @end group @end example @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 The template is: @example @group @@defvar @var{name} @var{body-of-definition} @@end defvar @end group @end example @code{@@defvar} creates an entry in the index of variables for @var{name}. @findex defopt @item @@defopt @var{name} @cindex User options, marking 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{}} and works like @code{@@defvar}. It creates an entry in the index of variables. @end table @node Typed Functions @subsection Functions in Typed Languages @cindex Typed functions @cindex Functions, in typed languages The @code{@@deftypefn} command and its variations are for describing functions in 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 are 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, the type of 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}). Since in typed languages, the actual names of the arguments are typically scattered among data type names and keywords, Texinfo cannot find them without help. You can either (a)@tie{}write everything as straight text, and it will be printed in slanted type; (b)@tie{}use @code{@@var} for the variable names, which will uppercase the variable names in Info and use the slanted typewriter font in printed output; (c)@tie{}use @code{@@var} for the variable names and @code{@@code} for the type names and keywords, which will be dutifully obeyed. The template for @code{@@deftypefn} is: @example @group @@deftypefn @var{category} @var{data-type} @var{name} @var{arguments} @dots{} @var{body-of-description} @@end deftypefn @end group @end example @noindent Note that if the @var{category} or @var{data type} is more than one word then it must be enclosed in braces to make it a single argument. If you are describing a procedure in a language that has packages, such as Ada, you might consider using @code{@@deftypefn} in a manner somewhat contrary to the convention described in the preceding paragraphs. For example: @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}.) @code{@@deftypefn} creates an entry in the index of functions for @var{name}. @item @@deftypefun @var{data-type} @var{name} @var{arguments}@dots{} @findex deftypefun The @code{@@deftypefun} command is the specialized definition command for functions in typed languages. The command is equivalent to @samp{@@deftypefn Function @dots{}}. The template is: @example @group @@deftypefun @var{type} @var{name} @var{arguments}@dots{} @var{body-of-description} @@end deftypefun @end group @end example @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 is to put the return type on a line by itself. So Texinfo provides an option to do that: @code{@@deftypefnnewline on}. This affects typed functions only---not untyped functions, 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 Typed Variables @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 @need 800 The template is: @example @@deftypevr @var{category} @var{data-type} @var{name} @var{body-of-description} @@end deftypevr @end example @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{}}. The template is: @example @group @@deftypevar @var{data-type} @var{name} @var{body-of-description} @@end deftypevar @end group @end example @end table These commands create entries in the index of variables. @node 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 @need 950 The template is: @example @group @@deftp @var{category} @var{name-of-type} @var{attributes}@dots{} @var{body-of-definition} @@end deftp @end group @end example @code{@@deftp} creates an entry in the index of data types. @end table @node Abstract Objects @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 @item @@defcv @var{category} @var{class} @var{name} @findex defcv 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. @item @@deftypecv @var{category} @var{class} @var{data-type} @var{name} @findex deftypecv 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. Ordinarily, the data type is a programming language construct that should be marked with @code{@@code}. For instance: @example @group @@deftypecv @{Class Option@} Window @@code@{int@} border-pattern @dots{} @@end deftypecv @end group @end example @noindent produces: @deftypecv {Class Option} Window @code{int} border-pattern @dots{} @end deftypecv @code{@@deftypecv} creates an entry in the index of variables. @item @@defivar @var{class} @var{name} @findex defivar 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. @item @@deftypeivar @var{class} @var{data-type} @var{name} @findex deftypeivar 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. Ordinarily, the data type is a programming language construct that should be marked with @code{@@code}. For instance: @example @group @@deftypeivar Window @@code@{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 general definition command for these method-like entities. 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. The template is: @example @group @@defop @var{category} @var{class} @var{name} @var{arguments}@dots{} @var{body-of-definition} @@end defop @end group @end example @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 definition command for typed operations in object-oriented programming. It is similar to @code{@@defop} with the addition of the @var{data-type} parameter to specify the return type of the method. @code{@@deftypeop} creates an entry in the index of functions. @item @@defmethod @var{class} @var{name} @var{arguments}@dots{} @findex defmethod 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. @item @@deftypemethod @var{class} @var{data-type} @var{name} @var{arguments}@dots{} @findex deftypemethod The @code{@@deftypemethod} command is the definition command for methods in object-oriented 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 the return type of the method. @code{@@deftypemethod} creates an entry in the index of functions. @end table The typed commands are affected by the @code{@@deftypefnnewline} option (@pxref{Typed Functions,, Functions in Typed Languages}). @node Def Cmd Conventions @section Conventions for Writing Definitions @cindex Definition conventions @cindex Conventions for writing definitions 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. @node Sample Function Definition @section A Sample Function Definition @cindex Function definitions @cindex Command definitions @cindex Macro definitions, programming-language @cindex Sample function definition A function definition uses the @code{@@defun} and @code{@@end defun} commands. The name of the function follows immediately after the @code{@@defun} command and it is followed, on the same line, by the parameter list. Here is a definition from @ref{Calling Functions,,, elisp, The GNU Emacs Lisp Reference Manual}. @quotation @defun apply function &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 looks like this: @example @group @@defun apply function &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}. Ordinary variables and user options are described using a format like that for functions except that variables do not take arguments. @node Internationalization @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}. @menu * @code{@@documentlanguage}:: Declaring the current language. * @code{@@documentencoding}:: Declaring the input encoding. @end menu @node @code{@@documentlanguage} @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. @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}}). In September 2006, the W3C Internationalization Activity released a new recommendation for specifying languages: @url{http://www.rfc-editor.org/rfc/bcp/bcp47.txt}. When Gettext supports this new scheme, Texinfo will too. @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{http://en.wikipedia.org/wiki/ISO_3166}. @node @code{@@documentencoding} @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 The @code{@@documentencoding} command declares the input document encoding, and can also affect the encoding of the output. Write it on a line by itself, with a valid encoding specification following, near the beginning of the file. @example @@documentencoding @var{enc} @end example Texinfo supports these encodings: @table @code @item US-ASCII This has no particular effect, but it's included for completeness. @item UTF-8 The vast global character encoding, expressed in 8-bit bytes. @item ISO-8859-1 @itemx ISO-8859-15 @itemx ISO-8859-2 @cindex Euro symbol, and encodings These specify the 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 is the commonly used encoding for the Russian language. @item koi8-u This is the commonly used encoding for the Ukrainian language. @end table Specifying an encoding @var{enc} has the following effects: @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 @var{enc}. This allows Info readers to set the encoding appropriately. It looks like this: @example Local Variables: coding: @var{enc} End: @end example Also, in Info and plain text output, unless the option @option{--disable-encoding} is given to @command{makeinfo}, accent constructs and special characters, such as @code{@@'e}, are output as the actual 8-bit or UTF-8 character in the given encoding where possible. @cindex HTML output, and encodings @cindex @code{http-equiv}, and charset specification @cindex @code{} HTML tag, and charset specification In HTML output, a @samp{} tag is output, in the @samp{} section of the HTML, that specifies @var{enc}. 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 @end example In XML and Docbook output, UTF-8 is always used for the output, according to the conventions of those formats. @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. (Our plan to support other scripts is to create a @LaTeX{} back-end to @command{texi2any}, where the support is already present.) For maximum portability of Texinfo documents across the many different user environments in the world, we recommend sticking to 7-bit ASCII in the input unless your particular manual needs a substantial amount of non-ASCII, e.g., it's written in German. You can use the @code{@@U} command to insert an occasional needed character (@pxref{Inserting Unicode}). @node Conditionals @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 @menu * Conditional Commands:: Text for a given format. * Conditional Not Commands:: Text for any format other than a given one. * Raw Formatter Commands:: Using raw formatter commands. * Inline Conditionals:: Brace-delimited conditional text. * @code{@@set @@clear @@value}:: Variable tests and substitutions. * Testing for Texinfo Commands:: Testing if a Texinfo command is available. * Conditional Nesting:: Using conditionals inside conditionals. @end menu @node Conditional Commands @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 by @TeX{} when it typesets the printed manual, and by @command{makeinfo} when not producing Info output. The segment of text appears only in the Info file and, for historical compatibility, the plain text output. @findex ifdocbook @findex ifhtml @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 @@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 @@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 @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 @section Conditional Not Commands @findex ifnotdocbook @findex ifnothtml @findex ifnotinfo @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 @@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 @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 ifhtml @findex html Analogously, you can use @code{@@ifhtml @dots{} @@end ifhtml} to delimit Texinfo source to be included in HTML output only, and @code{@@html @dots{} @@end html} for a region of raw HTML. @cindex XML, including raw @findex ifxml @findex xml Likewise, you can use @code{@@ifxml @dots{} @@end ifxml} to delimit Texinfo source to be included in XML output only, and @code{@@xml @dots{} @@end xml} for a region of raw XML@. Regions of raw text in other formats will also be present in the XML output, but with protection of XML characters and within corresponding elements. For example, the raw HTML text: @example @group @@html
@@end html @end group @end example @noindent will be included in the XML output as: @example @group <br /> @end group @end example @cindex Docbook, including raw @findex ifdocbook @findex docbook Again likewise, you can use @code{@@ifdocbook @dots{} @@end ifdocbook} to delimit Texinfo source to be included in Docbook output only, and @code{@@docbook @dots{} @@end docbook} for a region of raw Docbook. 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. Use the raw formatter commands for their intended purpose, of providing material directly in the underlying format. When you simply want to give different Texinfo specifications for different output formats, use the @code{@@if@dots{}} conditionals and stay in Texinfo syntax. @node Inline Conditionals @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 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} @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 are brief descriptions of these commands, see the following sections for more details: @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 @menu * @code{@@set @@value}:: Expand a flag variable to a string. * @code{@@ifset @@ifclear}:: Format a region if a flag is set. * @code{@@inlineifset @@inlineifclear}:: Brace-delimited flag conditionals. * @code{@@value} Example:: An easy way to update edition information. @end menu @node @code{@@set @@value} @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. 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. 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 formatters 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 formatters 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 formatters 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 formatters 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: @example @@set myletter a @@'@@value@{myletter@} @c fails! @end example @node @code{@@ifset @@ifclear} @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 either printed or Info 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; in both printed and Info output, 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} @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 @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 @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{makeinfo} 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 @section Conditional Nesting @cindex Conditionals, nested @cindex Nesting conditionals Conditionals can be nested; however, the details are a little tricky. The difficulty comes with failing conditionals, such as @code{@@ifhtml} when HTML is not being produced, where the included text is to be ignored. However, it is not to be @emph{completely} ignored, since it is useful to have one @code{@@ifset} inside another, for example---that is a way to include text only if two conditions are met. 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 Technically, Texinfo requires that for a failing conditional, the ignored text must be properly nested with respect to that failing conditional. 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 Finally, as mentioned above, all conditional commands must be on lines by themselves, with no text (even spaces) before or after. Otherwise, the processors cannot reliably determine which commands to consider for nesting purposes. @node Defining New Texinfo Commands @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{@@alias} is a convenient way to define a new name for an existing command. @item @samp{@@definfoenclose} allows you to define new commands with customized output for all non-@TeX{} output formats. @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}}). @menu * Defining Macros:: Defining and undefining new commands. * Invoking Macros:: Using a macro, once you've defined it. * Macro Details:: Limitations of Texinfo macros. * @code{@@alias}:: Command aliases. * @code{@@definfoenclose}:: Customized highlighting. * External Macro Processors:: @code{#line} directives. @end menu @node Defining Macros @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 For a macro to work consistently with @TeX{}, @var{macroname} must consist entirely of letters: no digits, hyphens, underscores, or other special characters. So, we recommend using only letters. However, @command{makeinfo} will accept anything consisting 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}). 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 @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. For @code{makeinfo}, 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, @command{makeinfo} implements two rules for @dfn{automatic quoting} in some circumstances: @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, @command{makeinfo} does not control 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{makeinfo} 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 @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 does not happen in the following contexts in @command{makeinfo}: @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. @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{makeinfo} 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 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 @@macro Mac @@iftex text for TeX output @@end iftex @@ifnottex text for not TeX output @@end ifnottex @@end macro @end example @noindent you can do the following instead: @example @@iftex @@macro Mac text for TeX output @@end macro @@end iftex @@ifnottex @@macro Mac text for not TeX output @@end macro @@end ifnottex @end example @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 Likewise, 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 work-around. Otherwise, the comma may be taken as separating the arguments. 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 makeinfo. better to avoid commas altogether using this trick. @c an alternative to @, could be invented if needed. @item Ending a macro body with @samp{@@c} may cause text following the macro invocation to be ignored as a comment in @command{makeinfo}. 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 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 @command{makeinfo} implementation also has the following limitations (by design): @itemize @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 In the @code{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{makeinfo}, 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} @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. @command{makeinfo} will accept the same identifiers for aliases as it does for macro names, that is, alphanumerics and (except as the first character) @samp{-}. @node @code{@@definfoenclose} @section @code{@@definfoenclose}: Customized Highlighting @anchor{definfoenclose}@c old name @cindex Highlighting, customized @cindex Customized highlighting @findex definfoenclose An @code{@@definfoenclose} command may be used to define a highlighting command for all the non-@TeX{} output formats. A command defined using @code{@@definfoenclose} marks text by enclosing it in strings that precede and follow the text. You can use this to get closer control of your output. Presumably, if you define a command with @code{@@definfoenclose}, you will create a corresponding command for @TeX{}, either in @file{texinfo.tex}, @file{texinfo.cnf}, or within an @samp{@@iftex} or @samp{@@tex} in your document. 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. If you do a @code{@@definfoenclose} on the name of a predefined command (such as @code{@@emph}, @code{@@strong}, @code{@@t}, or @code{@@i}), the enclosure definition will override the built-in definition. We don't recommend this. 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 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. For @TeX{} formatting, you could write @example @@iftex @@global@@let@@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 everything else. The raw @TeX{} commands need to be in @samp{@@iftex}. @code{@@definfoenclose} command need not be within @samp{@@ifinfo}, unless you want to use different definitions for different output formats. @findex headword Here is another example: write @example @@definfoenclose headword, , : @end example @noindent near the beginning of the file, to define @code{@@headword} as an Info formatting command that inserts nothing before and a colon after the argument to @code{@@headword}. @samp{@@definfoenclose} definitions must not be recursive, directly or indirectly. @node External Macro Processors @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. @menu * @samp{#line} Directive:: * TeX: @samp{#line} and @TeX{}. * Syntax: @samp{#line} Syntax Details. @end menu @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. @vindex CPP_LINE_DIRECTIVES The @command{makeinfo} 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} directives, not processing with @TeX{} As mentioned, @command{makeinfo} 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{makeinfo}'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{makeinfo} first to expand macros and eliminate @samp{#line}. @item If you run @command{makeinfo} or its variants (@pxref{Generic Translator @command{texi2any}}), you can specify @option{--no-ifinfo --iftex -E somefile.out}, and then give @file{somefile.out} to @code{texi2dvi} in a separate command. @item Or you can run @option{makeinfo --dvi --Xopt -E}. (Or @option{--pdf} instead of @option{--dvi}.) @command{makeinfo} 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. This is another example of why we recommend running @command{makeinfo} for the best diagnostics (@pxref{@command{makeinfo} Advantages}). @node @samp{#line} Syntax Details @subsection @samp{#line} Syntax Details @cindex @samp{#line} 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 filename, 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 filename (@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 @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. @menu * Using Include Files:: How to use the @code{@@include} command. * @code{texinfo-multiple-files-update}:: How to create and update nodes and menus when using included files. * Include Files Requirements:: @code{texinfo-multiple-files-update} needs. * Sample Include File:: A sample outer file with included files within it; and a sample included file. * @code{@@verbatiminclude}:: Including a file verbatim. * Include Files Evolution:: How use of the @code{@@include} command has changed over time. @end menu @node Using Include Files @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 @@-commands are expanded in file names. The one most likely to be useful is @code{@@value} (@pxref{@code{@@set @@value}}), and even then only in complicated situations. 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. @node @code{texinfo-multiple-files-update} @section @code{texinfo-multiple-files-update} @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: @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 @section 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 Sample Include 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 before running @code{texinfo-multiple-files-update}, which would insert a main or master menu: @example @group \input texinfo @@c -*-texinfo-*- @c %**start of header @@settitle Include Example @c %**end of header @end group ... @xref{Sample Texinfo Files}, for examples of the rest of the frontmatter ... @group @@ifnottex @@node Top @@top Include Example @@end ifnottex @end group @group @@include foo.texinfo @@include bar.texinfo @@include concept-index.texinfo @@bye @end group @end example An included file, such as @file{foo.texinfo}, 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.texinfo} might be as simple as this: @example @group @@node Concept Index @@unnumbered Concept Index @@printindex cp @end group @end example The outer Texinfo source file for @cite{The GNU Emacs Lisp Reference Manual} is named @file{elisp.texi}. This outer file contains a master menu with 417 entries and a list of 41 @code{@@include} files. @node @code{@@verbatiminclude} @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}}). The name of the file is taken literally, with a single exception: @code{@@value@{@var{var}@}} references are expanded. 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.) For a method on printing the file contents in a smaller font size, see the end of the section on @code{@@verbatim}. @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. @node Hardcopy @chapter Formatting and Printing Hardcopy @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, three major shell commands are used to print formatted output from a Texinfo manual: one converts the Texinfo source into something printable, a second sorts indices, and a third actually prints the formatted document. 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). If you are using GNU Emacs, you can use commands provided by Texinfo mode instead of shell commands. In addition to the three commands to format a file, sort the indices, and print the result, Texinfo mode offers key bindings for commands to recenter the output buffer, show the print queue, and delete a job from the print queue. Details are in the following sections. @menu * Use @TeX{}:: Use @TeX{} to format for hardcopy. * Format with @command{texi2dvi}:: The simplest way to format. * Format with @command{tex}/@command{texindex}:: Formatting with explicit shell commands. * Print with @command{lpr}:: How to print. * Within Emacs:: How to format and print from an Emacs shell. * Texinfo Mode Printing:: How to format and print in Texinfo mode. * Compile-Command:: How to print using Emacs's compile command. * Requirements Summary:: @TeX{} formatting requirements summary. * Preparing for @TeX{}:: What to do before you use @TeX{}. * Overfull hboxes:: What are and what to do with overfull hboxes. * @code{@@smallbook}:: How to print small format books and manuals. * A4 Paper:: How to print on A4 or A5 paper. * @code{@@pagesizes}:: How to print with customized page sizes. * Magnification:: How to print scaled up output. * PDF Output:: Portable Document Format output. * Obtaining @TeX{}:: How to obtain @TeX{}. @end menu @node Use @TeX{} @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. @xref{Obtaining @TeX{}}, for information on how to obtain @TeX{}. It is not included in the Texinfo package, being a vast suite of software in itself. @node Format with @command{texi2dvi} @section Format with @command{texi2dvi} @pindex texi2dvi @r{(shell script)} @cindex DVI, output in The @code{texi2dvi} program takes care of all the steps for producing a @TeX{} DVI file from a Texinfo document. Similarly, @code{texi2pdf} produces a PDF file. To run @code{texi2dvi} or @code{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 input filenames to @code{texi2dvi} and @code{texi2pdf} must include any extension, such as @samp{.texi}. (Under MS-DOS and perhaps in other circumstances, you may need to run @samp{sh texi2dvi foo.texi} instead of relying on the operating system to invoke the shell on the @samp{texi2dvi} script.) 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 (@pxref{PDF Output}), 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 @code{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{makeinfo} instead of the @TeX{} implementation (@pxref{Macro Details}). Each implementation has its own limitations and advantages. If this option is used, no line in the source file may begin with the string @code{@@c@tie{}_texi2dvi} or the string @code{@@c@tie{}(_texi2dvi)}. @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 @pindex pdfetex @command{texi2dvi} will use @command{etex} (or @command{pdfetex}) 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. (These days, @command{pdftex} and @command{pdfetex} are exactly the same, but we still run @command{pdfetex} to cater to ancient @TeX{} installations.) @cindex filename 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} @section Format with @command{tex}/@command{texindex} @cindex Shell formatting with @code{tex} and @code{texindex} @cindex Formatting with @code{tex} and @code{texindex} @cindex DVI file You can do the basic formatting of a Texinfo file with the shell command @code{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 @code{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 @code{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 @code{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 @code{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 @code{texindex} command reports but otherwise ignores such files. For each file specified, @code{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 @code{texindex} does not alter it. After you have sorted the indices, you need to rerun @code{tex} on the Texinfo file. This regenerates the output file, this time with up-to-date index entries. Finally, you may need to run @code{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 @code{texi2dvi}; see the previous section.) @enumerate @item Run @code{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 @code{texindex} on the raw index files. This creates the corresponding sorted index files (with three letter extensions). @item Run @code{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 @code{texindex}. @item Run @code{tex} one last time. This time the correct page numbers are written for the cross-references. @end enumerate @menu * Formatting Partial Documents:: * Details of @command{texindex}:: @end menu @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, 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 @code{makeinfo}, just like its @code{--no-validate} option (@pxref{Pointer Validation}). Furthermore, you need not run @code{texindex} each time after you run @code{tex}. The @code{tex} formatting command simply uses whatever sorted index files happen to exist from a previous use of @code{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 @code{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{http://en.wikipedia.org/wiki/Literate_programming}) using Texinfo for documentation and (portable) @code{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} @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 @code{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 @code{lpr} setup on your machine, you might 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 @code{texi2pdf} instead of @code{texi2dvi}; a PDF is often directly printable. Or you can generate a PCL file by using @code{dvilj} instead of @code{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} @code{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 Within Emacs @section Printing From an Emacs Shell @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 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}). In this shell, you can format and print the document. @xref{Hardcopy, , Format and Print Hardcopy}, for details. You can switch to and from the shell buffer while @code{tex} is running and do other editing. If you are formatting a long document on a slow machine, this can be very convenient. For example, you can use @code{texi2dvi} from an Emacs shell. Here is one way to use @code{texi2pdf} to format and print @cite{Using and Porting GNU CC} from a shell within Emacs: @example @group texi2pdf gcc.texi lpr gcc.pdf @end group @end example See the next section for more information about formatting and printing in Texinfo mode. @node Texinfo Mode Printing @section 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. @table @kbd @item C-c C-t C-b @itemx M-x texinfo-tex-buffer Run @code{texi2dvi} on the current buffer. @item C-c C-t C-r @itemx M-x texinfo-tex-region Run @TeX{} on the current region. @item C-c C-t C-i @itemx M-x texinfo-texindex Sort the indices of a Texinfo file formatted with @code{texinfo-tex-region}. @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 @code{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 @section 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 @code{tex} or @code{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 Requirements Summary @section @TeX{} Formatting Requirements Summary @cindex Requirements for formatting @cindex Minimal requirements for formatting @cindex Formatting requirements Every Texinfo file that is to be input to @TeX{} must begin with a @code{\input} command: @example \input texinfo @end example @noindent This instructs @TeX{} to load the macros it needs to process a Texinfo file. Every Texinfo file must end with a line that terminates @TeX{}'s processing and forces out unfinished pages: @example @@bye @end example Strictly speaking, these two lines are all a Texinfo file needs to be processed successfully by @TeX{}. Usually, however, the beginning includes a @code{@@settitle} command to define the title of the printed manual, a title page, a copyright page, permissions, and a table of contents. Besides @code{@@bye}, the end of a file usually includes indices. (Not to mention that most manuals contain a body of text as well.) For more information, see: @itemize @bullet @item @ref{@code{@@settitle}}. @item @ref{@code{@@setchapternewpage}}. @item @ref{Headings}. @item @ref{Titlepage & Copyright Page}. @item @ref{Printing Indices & Menus}. @item @ref{Contents}. @end itemize @node Preparing for @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, installing @cindex EC fonts, installing @cindex CM-Super fonts, 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}). @pindex feymr10@r{, 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.) On MS-DOS/MS-Windows, you'd do this like this (note the use of the @samp{;} character as directory separator, instead of @samp{:}): @example set TEXINPUTS=.;d:/home/me/mylib;c: @end example @noindent It is customary for DOS/Windows users to put such commands in the @file{autoexec.bat} file, or in the Windows registry. @node 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 @code{@@smallbook} @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. However, you can direct @TeX{} 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.) If you write the @code{@@smallbook} command between the start-of-header and end-of-header lines, the Texinfo mode @TeX{} region formatting command, @code{texinfo-tex-region}, will format the region in ``small'' book size (@pxref{Start of Header}). @xref{@code{@@small@dots{}}}, for information about commands that make it easier to produce examples for a smaller manual. @xref{Format with @command{texi2dvi}}, and @ref{Preparing for @TeX{}}, for other ways to format with @code{@@smallbook} that do not require changing the source file. @node A4 Paper @section Printing on A4 Paper @cindex A4 paper, printing on @cindex A5 paper, printing on @cindex Paper size, A4 @cindex European A4 paper @findex afourpaper @findex afivepaper You can tell @TeX{} to format a document for printing on European size A4 paper (or A5) with the @code{@@afourpaper} (or @code{@@afivepaper}) command. Write the command on a line by itself near the beginning of the Texinfo file, before the title page. For example, this is how you would write the header for this manual: @example @group \input texinfo @@c -*-texinfo-*- @@c %**start of header @@settitle Texinfo @@afourpaper @@c %**end of header @end group @end example @xref{Format with @command{texi2dvi}}, and @ref{Preparing for @TeX{}}, for other ways to format for different paper sizes that do not require changing the source file. @findex afourlatex @findex afourwide 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. @node @code{@@pagesizes} @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}}, and @ref{Preparing for @TeX{}}, for other ways to specify @code{@@pagesizes} that do not require changing the source file. @node Magnification @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 PDF Output @section PDF Output @cindex PDF output @cindex Output, in PDF @pindex pdftex The simplest way to generate PDF output from Texinfo source is to run the convenience script @command{texi2pdf} (or @command{pdftexi2dvi}); this executes the @command{texi2dvi} script with the @option{--pdf} option (@pxref{Format with @command{texi2dvi}}). If for some reason you want to process the document by hand, you can run the @command{pdftex} program instead of plain @command{tex}. That is, run @samp{pdftex foo.texi} instead of @samp{tex foo.texi}. @dfn{PDF} stands for `Portable Document Format'. It was invented by Adobe Systems some years ago for document interchange, based on their PostScript language. Related links: @itemize @item GNU GV, a @uref{http://www.gnu.org/software/gv/, Ghostscript-based PDF reader}. (It can also preview PostScript documents.) @item @code{xpdf}, a freely available standalone @uref{http://www.foolabs.com/xpdf/, PDF reader} for the X window system. @item @uref{https://en.wikipedia.org/wiki/Portable_Document_Format, PDF at Wikipedia}. @end itemize At present, Texinfo does not provide @samp{@@ifpdf} or @samp{@@pdf} commands as for the other output formats, since PDF documents contain many internal low-level offsets and cross-references that would be hard or impossible to specify at the Texinfo source level. PDF files require dedicated software to be displayed, unlike the plain ASCII formats (Info, HTML) that Texinfo supports. They also tend to be much larger than the DVI files output by @TeX{} by default. Nevertheless, a PDF file does define an actual typeset document in a self-contained file, notably including all the fonts that are used, so it has its place. @node Obtaining @TeX{} @section 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 Generic Translator @command{texi2any} @chapter @command{texi2any}: The Generic 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: @table @asis @item Info (by default, or with @option{--info}), @item HTML (with @option{--html}), @item plain text (with @option{--plaintext}), @item Docbook (with @option{--docbook}), @item Texinfo XML (with @option{--xml}). @end table @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. The rest of this chapter goes into the details. @menu * Reference Implementation:: @command{texi2any}: the reference implementation. * Invoking @command{texi2any}:: Running the translator from a shell. * @command{texi2any} Environment Variables:: * @command{texi2any} Printed Output:: Calling @command{texi2dvi}. * Pointer Validation:: How to check that pointers point somewhere. * Customization Variables:: Configuring @command{texi2any}. * Internationalization of Document Strings:: Translating program-inserted text. * Invoking @command{pod2texi}:: Translating Perl pod to Texinfo. * @command{texi2html}:: An ancestor of @command{texi2any}. @end menu @node Reference Implementation @section @command{texi2any}: A Texinfo Reference Implementation @cindex @command{texi2any}, as reference implementation @cindex Reference implementation @cindex Implementation, @command{texi2any} as reference Above, we called @command{texi2any} ``the'' translator for Texinfo instead of just ``a'' translator, even though (of course) it's technically and legally possible for other implementations to be written. The reason is that alternative implementations are very likely to have subtle, or not-so-subtle, differences in behavior, and thus Texinfo documents would become dependent on the processor. Therefore, it is important to have a reference implementation that defines parts of the language not fully specified by the manual (often intentionally so). It is equally important to have consistent command-line options and other behavior for all processors. @cindex Tree representation of documents @cindex Syntax tree representation of documents @cindex Abstract syntax tree representation of documents For this reason, the once-independent @command{texi2html} Perl Texinfo processor was made compatible with the C implementation of @command{makeinfo}, to avoid continuing with two different implementations (@pxref{History}). The current implementation, @command{texi2any}, serves as the reference implementation. It inherited the design of customization and other features from @command{texi2html} (for more on @command{texi2html} compatibility, @pxref{@command{texi2html}}). However, @code{texi2any} is a full reimplementation: it constructs a tree-based representation of the input document for all back-ends to work from. @cindex Texinfo language tests @cindex Tests, of Texinfo language Extensive tests of the language were developed at the same time as @command{texi2any}; we plead with anyone thinking of writing a program to parse Texinfo input to at least make use of these tests. @cindex Examples of using @command{texi2any} @findex Texinfo::Parser module The @command{texi2html} wrapper script (@pxref{@command{texi2html}}) provides a very simple example of calling @command{texi2any} from a shell script; it's in @file{util/texi2html} in the Texinfo sources. More consequentially, @command{texi-elements-by-size} is an example Perl script using the @code{Texinfo::Parser} module interface; it's also in the @file{util} source directory. (Its functionality may also be useful to authors; @pxref{texi-elements-by-size}.) @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 Invoking @command{texi2any} @section Invoking @command{texi2any}/@command{makeinfo} from a Shell @anchor{Invoking makeinfo} @pindex makeinfo @pindex texi2any To process a Texinfo file, invoke @command{texi2any} or @command{makeinfo} (the two names are synonyms for the same program; we'll use the names interchangeably) 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.texinfo @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 @code{makeinfo} options @cindex Options for @code{makeinfo} @anchor{texi2any Options} @cindex @code{texi2any} options @cindex Options for @code{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.texinfo} in which lines are filled to only 68 columns: @example texi2any --fill-column=68 bison.texinfo @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{path} @opindex --conf-dir=@var{path} Prepend @var{path} to the directory search list for finding customization files that may be loaded with @option{--init-file} (see below). The @var{path} 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 W3C cascading style sheets specifications, in the @samp{