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This is Info file texinfo, produced by Makeinfo-1.47 from the input file texinfo2.tex. This file documents Texinfo, a documentation system that uses a single source file to produce both on-line information and a printed manual. Copyright (C) 1988, 1990, 1991, 1992 Free Software Foundation, Inc. This is the second edition of the Texinfo documentation, and is consistent with version 2 of `texinfo.tex'. Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies. Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one. Permission is granted to copy and distribute translations of this manual into another language, under the above conditions for modified versions, except that this permission notice may be stated in a translation approved by the Foundation. File: texinfo, Node: titlefont center sp, Next: title subtitle author, Prev: titlepage, Up: Titlepage & Copyright Page `@titlefont', `@center', and `@sp' ---------------------------------- You can use the `@titlefont', `@sp', and `@center' commands to create a title page for a printed document. (This is the first of the two methods for creating a title page in Texinfo.) Use the `@titlefont' command to select a large font suitable for the title itself. For example: @titlefont{Texinfo} Use the `@center' command at the beginning of a line to center the remaining text on that line. Thus, @center @titlefont{Texinfo} centers the title, which in this example is "Texinfo" printed in the title font. Use the `@sp' command to insert vertical space. For example: @sp 2 This inserts two blank lines on the printed page. (*Note `@sp': sp, for more information about the `@sp' command.) A template for this method looks like this: @titlepage @sp 10 @center @titlefont{NAME-OF-MANUAL-WHEN-PRINTED} @sp 2 @center SUBTITLE-IF-ANY @sp 2 @center AUTHOR ... @end titlepage The spacing of the example fits an 8 1/2 by 11 inch manual. File: texinfo, Node: title subtitle author, Next: Copyright & Permissions, Prev: titlefont center sp, Up: Titlepage & Copyright Page `@title', `@subtitle', and `@author' ------------------------------------ You can use the `@title', `@subtitle', and `@author' commands to create a title page in which the vertical and horizontal spacing is done for you automatically. This contrasts with the method described in the previous section, in which the `@sp' command is needed to adjust vertical spacing. Write the `@title', `@subtitle', or `@author' commands at the beginning of a line followed by the title, subtitle, or author. The `@title' command produces a line in which the title is set flush to the left-hand side of the page in a larger than normal font. The title is underlined with a black rule. The `@subtitle' command sets subtitles in a normal-sized font flush to the right-hand side of the page. The `@author' command sets the names of the author or authors in a middle-sized font flush to the left-hand side of the page on a line near the bottom of the title page. The names are underlined with a black rule that is thinner than the rule that underlines the title. (The black rule only occurs if the `@author' command line is followed by an `@page' command line.) There are two ways to use the `@author' command: you can write the name or names on the remaining part of the line that starts with an `@author' command: @author by Jane Smith and John Doe or you can write the names one above each other by using two (or more) `@author' commands: @author Jane Smith @author John Doe (Only the bottom name is underlined with a black rule.) A template for this method looks like this: @titlepage @title NAME-OF-MANUAL-WHEN-PRINTED @subtitle SUBTITLE-IF-ANY @subtitle SECOND-SUBTITLE @author AUTHOR @page ... @end titlepage Contrast this form with the form of a title page written using the `@sp', `@center', and `@titlefont' commands: @titlepage @sp 10 @center @titlefont{Name of Manual When Printed} @sp 2 @center Subtitle, If Any @sp 1 @center Second subtitle @sp 2 @center Author @page ... @end titlepage File: texinfo, Node: Copyright & Permissions, Next: end titlepage, Prev: title subtitle author, Up: Titlepage & Copyright Page Copyright Page and Permissions ------------------------------ By international treaty, the copyright notice for a book should be either on the title page or on the back of the title page. The copyright notice should include the year followed by the name of the organization or person who owns the copyright. When the copyright notice is on the back of the title page, that page is customarily not numbered. Therefore, in Texinfo, the information on the copyright page should be within `@titlepage' and `@end titlepage' commands. Use the `@page' command to cause a page break. To push the copyright notice and the other text on the copyright page towards the bottom of the page, you can write a somewhat mysterious line after the `@page' command that reads like this: @vskip 0pt plus 1filll This is a TeX command that is not supported by the Info formatting commands. The `@vskip' command inserts whitespace. The `0pt plus 1filll' means to put in zero points of mandatory whitespace, and as much optional whitespace as needed to push the following text to the bottom of the page. Note the use of three `l's in the word `filll'; this is the correct usage in TeX. In a printed manual, the `@copyright{}' command generates a `c' inside a circle. (In Info, it generates `(C)'.) The copyright notice itself has the following legally defined sequence: Copyright (C) YEAR COPYRIGHT-OWNER It is customary to put information on how to get a manual after the copyright notice, followed by the copying permissions for the manual. Note that permissions must be given here as well as in the summary segment within `@ifinfo' and `@end ifinfo' that immediately follows the header since this text appears only in the printed manual and the `ifinfo' text appears only in the Info file. *Note Sample Permissions::, for the standard text. File: texinfo, Node: end titlepage, Next: headings on off, Prev: Copyright & Permissions, Up: Titlepage & Copyright Page Heading Generation ------------------ An `@end titlepage' command on a line by itself not only marks the end of the title and copyright pages, but also causes TeX to start generating page headings and page numbers. To repeat what is said elsewhere, Texinfo has two standard page heading formats, one for documents which are printed on one side of each sheet of paper (single-sided printing), and the other for documents which are printed on both sides of each sheet (double-sided printing). (*Note `@setchapternewpage': setchapternewpage.) You can specify these formats in different ways: * The conventional way is to write an `@setchapternewpage' command before the title page commands, and then have the `@end titlepage' command start generating page headings in the manner desired. (*Note `@setchapternewpage': setchapternewpage.) * Alternatively, you can use the `@headings' command to prevent page headings from being generated or to start them for either single or double-sided printing. (Write an `@headings' command immediately after the `@end titlepage' command. *Note The `@headings' Command: headings on off, for more information.) * Or, you may specify your own page heading and footing format. *Note Page Headings: Headings, for detailed information about page headings and footings. Most documents are formatted with the standard single-sided or double-sided format, using `@setchapternewpage odd' for double-sided printing and no `@setchapternewpage' command for single-sided printing. File: texinfo, Node: headings on off, Prev: end titlepage, Up: Titlepage & Copyright Page The `@headings' Command ----------------------- The `@headings' command is rarely used. It specifies what kind of page headings and footings to print on each page. Usually, this is controlled by the `@setchapternewpage' command. You need the `@headings' command only if the `@setchapternewpage' command does not do what you want, or if you want to turn off pre-defined page headings prior to defining your own. Write an `@headings' command immediately after the `@end titlepage' command. There are four ways to use the `@headings' command: `@headings off' Turn off printing of page headings. `@headings single' Turn on page headings appropriate for single-sided printing. `@headings double' `@headings on' Turn on page headings appropriate for double-sided printing. The two commands, `@headings on' and `@headings double', are synonymous. For example, suppose you write `@setchapternewpage off' before the `@titlepage' command to tell TeX to start a new chapter on the same page as the end of the last chapter. This command also causes TeX to typeset page headers for single-sided printing. To cause TeX to typeset for double sided printing, write `@headings double' after the `@end titlepage' command. You can stop TeX from generating any page headings at all by writing `@headings off' on a line of its own immediately after the line containing the `@end titlepage' command, like this: @end titlepage @headings off The `@headings off' command overrides the `@end titlepage' command, which would otherwise cause TeX to print page headings. You can also specify your own style of page heading and footing. *Note Page Headings: Headings, for more information. File: texinfo, Node: The Top Node, Next: Software Copying Conditions, Prev: Titlepage & Copyright Page, Up: Beginning a File The `Top' Node and Master Menu ============================== The `Top' node is the node from which you enter an Info from outside. A `Top' node should contain a brief description of the Info file and an extensive, master menu for the whole Info file. This helps the reader understand what the Info file is about. Also, you should write the version number of the program to which the Info file applies; or, at least, the edition number. The contents of the `Top' node should appear only in the Info file; none of it should appear in printed output, so enclose it between `@ifinfo' and `@end ifinfo' commands. (TeX does not print either an `@node' line or a menu; they appear only in Info; strictly speaking, you are not required to enclose these parts between `@ifinfo' and `@end ifinfo', but it is simplest to do so. *Note Conditionally Visible Text: Conditionals.) * Menu: * Title of Top Node:: Sketch what the file is about. * Master Menu Parts:: A master menu has three or more parts. File: texinfo, Node: Title of Top Node, Next: Master Menu Parts, Up: The Top Node `Top' Node Title ---------------- Sometimes, you will want to place an `@top' sectioning command line containing the title of the document immediately after the `@node Top' line (*note The `@top' Sectioning Command: makeinfo top command., for more information). For example, the beginning of the Top node of this manual contains an `@top' sectioning command, a short description, and edition and version information. It looks like this: ... @end titlepage @ifinfo @node Top, Copying, (dir), (dir) @top Texinfo Texinfo is a documentation system... This is edition... ... @end ifinfo @menu * Copying:: Texinfo is freely redistributable. * Overview:: What is Texinfo? ... @end menu In a `Top' node, the `Previous', and `Up' nodes usually refer to the top level directory of the whole Info system, which is called `(dir)'. File: texinfo, Node: Master Menu Parts, Prev: Title of Top Node, Up: The Top Node Parts of a Master Menu ---------------------- A "master menu" is a detailed main menu listing all the nodes in a file. A master menu is enclosed in `@menu' and `@end menu' commands and does not appear in the printed document. Generally, a master menu is divided into parts. * The first part contains the major nodes in the Texinfo file: the nodes for the chapters, chapter-like sections, and the appendices. * The second part contains nodes for the indices. * The third and subsequent parts contain a listing of the other, lower level nodes, often ordered by chapter. This way, rather than go through an intermediary menu, an inquirer can go directly to a particular node when searching for specific information. These menu items are not required; add them if you think they are a convenience. Each section in the menu can be introduced by a descriptive line. So long as the line does not begin with an asterisk, it will not be treated as a menu entry. (*Note Writing a Menu::, for more information.) For example, the master menu for this manual looks like the following (but has many more entries): @menu * Copying:: Texinfo is freely redistributable. * Overview:: What is Texinfo? * Texinfo Mode:: Special features in GNU Emacs. ... ... * Command and Variable Index:: An entry for each @-command. * Concept Index:: An entry for each concept. --- The Detailed Node Listing --- Overview of Texinfo * Info Files:: What is an Info file? * Printed Manuals:: Characteristics of a printed manual. ... ... Using Texinfo Mode * Info on a Region:: Formatting part of a file for Info. ... ... @end menu File: texinfo, Node: Software Copying Conditions, Prev: The Top Node, Up: Beginning a File Software Copying Conditions =========================== If the Texinfo file has a section containing the "General Public License" and the distribution information and a warranty disclaimer for the software that is documented, this section usually follows the `Top' node. The General Public License is very important to Project GNU software. It ensures that you and others will continue to have a right to use and share the software. The copying and distribution information and the disclaimer are followed by an introduction or else by the first chapter of the manual. Although an introduction is not a required part of a Texinfo file, it is very helpful. Ideally, it should state clearly and concisely what the file is about and who would be interested in reading it. In general, an introduction would follow the licensing and distribution information, although sometimes people put it earlier in the document. Usually, an introduction is put in an `@unnumbered' section. (*Note The `@unnumbered' and `@appendix' Commands: unnumbered & appendix.) File: texinfo, Node: Ending a File, Next: Structuring, Prev: Beginning a File, Up: Top Ending a Texinfo File ********************* The end of a Texinfo file should include the commands that create indices and generate detailed and summary tables of contents. And it must include the `@bye' command that marks the last line processed by TeX. For example: @node Concept Index, , Variables Index, Top @comment node-name, next, previous, up @unnumbered Concept Index @printindex cp @contents @bye * Menu: * Printing Indices & Menus:: How to print an index in hardcopy and generate index menus in Info. * Contents:: How to create a table of contents. * File End:: How to mark the end of a file. File: texinfo, Node: Printing Indices & Menus, Next: Contents, Up: Ending a File Index Menus and Printing an Index ================================= 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 `@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 `@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 `texindex' (*note Format/Print 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 different types of predefined index: the concept index, the function index, the variables index, the keystroke index, the program index, and the data type index (*note Predefined Indices::.). Each index type has a two-letter name: `cp', `fn', `vr', `ky', `pg', and `tp'. You may merge indices, or put them into separate sections (*note Combining Indices::.). The `@printindex' command takes a two-letter index name, reads the corresponding sorted index file and formats it appropriately into an index. The `@printindex' command does not generate a chapter heading for the index. Consequently, you should precede the `@printindex' command with a suitable section or chapter command (usually `@unnumbered') to supply the chapter heading and put the index into the table of contents. Precede the `@unnumbered' command with an `@node' line. For example: @node Variables Index, Concept Index, Function Index, Top @comment node-name, next, previous, up @unnumbered Variable Index @printindex vr @node Concept Index, , Variables Index, Top @comment node-name, next, previous, up @unnumbered Concept Index @printindex cp @summarycontents @contents @bye (Readers often prefer that the concept index come last in a book, since that makes it easiest to find.) File: texinfo, Node: Contents, Next: File End, Prev: Printing Indices & Menus, Up: Ending a File Generating a Table of Contents ============================== The `@chapter', `@section', and other structuring commands supply the information to make up a table of contents, but they do not cause an actual table to appear in the manual. To do this, you must use the `@contents' and `@summarycontents' commands: `@contents' Generate a table of contents in a printed manual, including all chapters, sections, subsections, etc., as well as appendices and unnumbered chapters. (Headings generated by the `@heading' series of commands do not appear in the table of contents.) The `@contents' command should be written on a line by itself. `@shortcontents' `@summarycontents' (`@summarycontents' is a synonym for `@shortcontents'; the two commands are exactly the same.) Generate a short or summary table of contents that lists only the chapters (and appendices and unnumbered chapters). Omit sections, subsections and subsubsections. Only a long manual needs a short table of contents in addition to the full table of contents. Write the `@shortcontents' command on a line by itself right *before* the `@contents' command. The table of contents commands automatically generate a chapter-like heading at the top of the first table of contents page. Write the table of contents commands at the very end of a Texinfo file, just before the `@bye' command, following any index sections--anything in the Texinfo file after the table of contents commands will be omitted from the table of contents. When you print a manual with a table of contents, the table of contents will be printed last and numbered with roman numerals. You need to place those pages in their proper place, after the title page, yourself. (This is the only collating you need to do for a printed manual. The table of contents is printed last because it is generated after the rest of the manual is typeset.) Here is an example of where to write table of contents commands: INDICES... @shortcontents @contents @bye Since an Info file uses menus instead of tables of contents, the Info formatting commands ignore the `@contents' and `@shortcontents' commands. File: texinfo, Node: File End, Prev: Contents, Up: Ending a File `@bye' File Ending ================== An `@bye' command terminates TeX or Info formatting. None of the formatting commands see any of the file following `@bye'. The `@bye' command should be on a line by itself. If you wish, you may follow the `@bye' line with notes. These notes will not be formatted and will not appear in either Info or a printed manual; it is as if text after `@bye' were within `@ignore' ... `@end ignore'. Also, you may follow the `@bye' line with a local variables list. *Note Using Local Variables and the Compile Command: Compile-Command, for more information. File: texinfo, Node: Structuring, Next: Nodes, Prev: Ending a File, Up: Top Chapter Structuring ******************* The "chapter structuring" commands divide a document into a hierarchy of chapters, sections, subsections, and subsubsections. These commands generate large headings; they also provide information for the table of contents of a printed manual (*note Generating a Table of Contents: Contents.). The chapter structuring commands do not create an Info node structure, so normally you should put an `@node' command immediately before each chapter structuring command (*note Nodes::.). The only time you are likely to use the chapter structuring commands without using the node structuring commands is if you are writing a document that contains no cross references and will never be transformed into Info format. It is unlikely that you will ever write a Texinfo file that is intended only as an Info file and not as a printable document. If you do, you might still use chapter structuring commands to create a heading at the top of each node--but you don't need to. * Menu: * Tree Structuring:: A manual is like an upside down tree ... * Structuring Command Types:: How to divide a manual into parts. * makeinfo top:: The `@top' command, part of the `Top' node. * chapter:: * unnumbered & appendix:: * majorheading & chapheading:: * section:: * unnumberedsec appendixsec heading:: * subsection:: * unnumberedsubsec appendixsubsec subheading:: * subsubsection:: Commands for the lowest level sections. File: texinfo, Node: Tree Structuring, Next: Structuring Command Types, Up: Structuring Tree Structure of Sections ========================== A Texinfo file is usually structured like a book with chapters, sections, subsections, and the like. This structure can be visualized as a tree (or rather as an upside-down tree) with the root at the top and the levels corresponding to chapters, sections, subsection, and subsubsections. Here is a diagram that shows a Texinfo file with three chapters, each of which has two sections. Top | ------------------------------------- | | | Chapter 1 Chapter 2 Chapter 3 | | | -------- -------- -------- | | | | | | Section Section Section Section Section Section 1.1 1.2 2.1 2.2 3.1 3.2 In a Texinfo file that has this structure, the beginning of Chapter 2 looks like this: @node Chapter 2, Chapter 3, Chapter 1, top @chapter Chapter 2 The chapter structuring commands are described in the sections that follow; the `@node' and `@menu' commands are described in following chapters. (*Note Nodes::, and see *Note Menus::.) File: texinfo, Node: Structuring Command Types, Next: makeinfo top, Prev: Tree Structuring, Up: Structuring Types of Structuring Command ============================ The chapter structuring commands fall into four groups or series, each of which contains structuring commands corresponding to the hierarchical levels of chapters, sections, subsections, and subsubsections. The four groups are the `@chapter' series, the `@unnumbered' series, the `@appendix' series, and the `@heading' series. Each command produces titles that have a different appearance on the printed page or Info file; only some of the commands produce titles that are listed in the table of contents of a printed book or manual. * The `@chapter' and `@appendix' series of commands produce numbered or lettered entries both in the body of a printed work and in its table of contents. * The `@unnumbered' series of commands produce unnumbered entries both in the body of a printed work and in its table of contents. The `@top' command, which has a special use, is a member of this series (*note `@top': makeinfo top.). * The `@heading' series of commands produce unnumbered headings that do not appear in a table of contents. The heading commands never start a new page. * The `@majorheading' command produces results similar to using the `@chapheading' command but generates a larger vertical whitespace before the heading. * When an `@setchapternewpage' command says to do so, the `@chapter', `@unnumbered', and `@appendix' commands start new pages in the printed manual; the `@heading' commands do not. Here are the four groups of chapter structuring commands: No new pages Numbered Unnumbered Lettered and numbered Unnumbered In contents In contents In contents Not in contents @top @majorheading @chapter @unnumbered @appendix @chapheading @section @unnumberedsec @appendixsec @heading @subsection @unnumberedsubsec @appendixsubsec @subheading @subsubsection @unnumberedsubsubsec @appendixsubsubsec @subsubheading File: texinfo, Node: makeinfo top, Next: chapter, Prev: Structuring Command Types, Up: Structuring `@top' ====== The `@top' command is a special sectioning command that you use only after an `@node Top' line at the beginning of a Texinfo file. The `@top' command tells the `makeinfo' formatter which node is the `Top' node. It has the same typesetting effect as `@unnumbered' (*note `@unnumbered': (`@appendix')unnumbered & appendix.). For detailed information, see *Note The `@top' Command: makeinfo top command. File: texinfo, Node: chapter, Next: unnumbered & appendix, Prev: makeinfo top, Up: Structuring `@chapter' ========== `@chapter' identifies a chapter in the document. Write the command at the beginning of a line and follow it on the same line by the title of the chapter. For example, this chapter in this manual is entitled "Chapter Structuring"; the `@chapter' line looks like this: @chapter Chapter Structuring In TeX, the `@chapter' command creates a chapter in the document, specifying the chapter title. The chapter is numbered automatically. In Info, the `@chapter' command causes the title to appear on a line by itself, with a line of asterisks inserted underneath. Thus, in Info, the above example produces the following output: Chapter Structuring ******************* File: texinfo, Node: unnumbered & appendix, Next: majorheading & chapheading, Prev: chapter, Up: Structuring `@unnumbered', `@appendix' ========================== Use the `@unnumbered' command to create a chapter that appears in a printed manual without chapter numbers of any kind. Use the `@appendix' command to create an appendix in a printed manual that is labelled by letter instead of by number. For Info file output, the `@unnumbered' and `@appendix' commands are equivalent to `@chapter': the title is printed on a line by itself with a line of asterisks underneath. (*Note `@chapter': chapter.) To create an appendix or an unnumbered chapter, write an `@appendix' or `@unnumbered' command at the beginning of a line and follow it on the same line by the title, as you would if you were creating a chapter. File: texinfo, Node: majorheading & chapheading, Next: section, Prev: unnumbered & appendix, Up: Structuring `@majorheading', `@chapheading' =============================== The `@majorheading' and `@chapheading' commands put chapter-like headings in the body of a document. However, neither command causes TeX to produce a numbered heading or an entry in the table of contents; and neither command causes TeX to start a new page in a printed manual. In TeX, an `@majorheading' command generates a larger vertical whitespace before the heading than an `@chapheading' command but is otherwise the same. In Info, the `@majorheading' and `@chapheading' commands are equivalent to `@chapter': the title is printed on a line by itself with a line of asterisks underneath. (*Note `@chapter': chapter.) File: texinfo, Node: section, Next: unnumberedsec appendixsec heading, Prev: majorheading & chapheading, Up: Structuring `@section' ========== In a printed manual, an `@section' command identifies a numbered section within a chapter. The section title appears in the table of contents. In Info, an `@section' command provides a title for a segment of text, underlined with `='. This section is headed with an `@section' command and looks like this in the Texinfo file: @section @code{@@section} To create a section, write the `@section' command at the beginning of a line and follow it on the same line by the section title. Thus, @section This is a section produces This is a section ================= in Info. File: texinfo, Node: unnumberedsec appendixsec heading, Next: subsection, Prev: section, Up: Structuring `@unnumberedsec', `@appendixsec', `@heading' ============================================ The `@unnumberedsec', `@appendixsec', and `@heading' commands are, respectively, the unnumbered, appendix-like, and heading-like equivalents of the `@section' command. (*Note `@section': section.) `@unnumberedsec' The `@unnumberedsec' command may be used within an unnumbered chapter or within a regular chapter or appendix to provide an unnumbered section. `@appendixsec' `@appendixsection' `@appendixsection' is a longer spelling of the `@appendixsec' command; the two are synonymous. Conventionally, the `@appendixsec' or `@appendixsection' command is used only within appendices. `@heading' You may use the `@heading' command anywhere you wish for a section-style heading that will not appear in the table of contents. File: texinfo, Node: subsection, Next: unnumberedsubsec appendixsubsec subheading, Prev: unnumberedsec appendixsec heading, Up: Structuring The `@subsection' Command ========================= Subsections are to sections as sections are to chapters. (*Note `@section': section.) In Info, subsection titles are underlined with `-'. For example, @subsection This is a subsection produces This is a subsection -------------------- In a printed manual, subsections are listed in the table of contents and are numbered three levels deep. File: texinfo, Node: unnumberedsubsec appendixsubsec subheading, Next: subsubsection, Prev: subsection, Up: Structuring The `@subsection'-like Commands =============================== The `@unnumberedsubsec', `@appendixsubsec', and `@subheading' commands are, respectively, the unnumbered, appendix-like, and heading-like equivalents of the `@subsection' command. (*Note `@subsection': subsection.) In Info, the `@subsection'-like commands generate a title underlined with hyphens. In a printed manual, an `@subheading' command produces a heading like that of a subsection except that it is not numbered and does not appear in the table of contents. Similarly, an `@unnumberedsubsec' command produces an unnumbered heading like that of a subsection and an `@appendixsubsec' command produces a subsection-like heading labelled with a letter and numbers; both of these commands produce headings that appear in the table of contents. File: texinfo, Node: subsubsection, Prev: unnumberedsubsec appendixsubsec subheading, Up: Structuring The `subsub' Commands ===================== The fourth and lowest level sectioning commands in Texinfo are the `subsub' commands. They are: `@subsubsection' Subsubsections are to subsections as subsections are to sections. (*Note `@subsection': subsection.) In a printed manual, subsubsection titles appear in the table of contents and are numbered four levels deep. `@unnumberedsubsubsec' Unnumbered subsubsection titles appear in the table of contents of a printed manual, but lack numbers. Otherwise, unnumbered subsubsections are the same as subsubsections. In Info, unnumbered subsubsections look exactly like ordinary subsubsections. `@appendixsubsubsec' Conventionally, appendix commands are used only for appendices and are lettered and numbered appropriately in a printed manual. They also appear in the table of contents. In Info, appendix subsubsections look exactly like ordinary subsubsections. `@subsubheading' The `@subsubheading' command may be used anywhere that you need a small heading that will not appear in the table of contents. In Info, subsubheadings look exactly like ordinary subsubsection headings. In Info, `subsub' titles are underlined with periods. For example, @subsubsection This is a subsubsection produces This is a subsubsection ....................... File: texinfo, Node: Nodes, Next: Menus, Prev: Structuring, Up: Top Nodes ***** "Nodes" are the primary segments of a Texinfo file. They do not themselves impose a hierarchic or any other kind of structure on a file. Nodes contain "node pointers" that name other nodes, and can contain "menus" which are lists of nodes. In Info, the movement commands can carry you to a pointed-to node or to a node listed in a menu. Node pointers and menus provide structure for Info files just as chapters, sections, subsections, and the like, provide structure for printed books. * Menu: * Two Paths:: Different commands to structure Info output and printed output. * Node Menu Illustration:: A diagram, and sample nodes and menus. * node:: How to write a node, in detail. * makeinfo Pointer Creation:: How to create node pointers with `makeinfo'. File: texinfo, Node: Two Paths, Next: Node Menu Illustration, Up: Nodes Two Paths ========= The node and menu commands and the chapter structuring commands are independent of each other: * In Info, node and menu commands provide structure. The chapter structuring commands generate headings with different kinds of underlining--asterisks for chapters, hyphens for sections, and so on; they do nothing else. * In TeX, the chapter structuring commands generate chapter and section numbers and tables of contents. The node and menu commands provide information for cross references; they do nothing else. You can use node pointers and menus to structure an Info file any way you want; and you can write a Texinfo file so that its Info output has a different structure than its printed output. However, most Texinfo files are written such that the structure for the Info output corresponds to the structure for the printed output. It is not convenient to do otherwise. Generally, printed output is structured in a tree-like hierarchy in which the chapters are the major limbs from which the sections branch out. Similarly, node pointers and menus are organized to create a matching structure in the Info output. File: texinfo, Node: Node Menu Illustration, Next: node, Prev: Two Paths, Up: Nodes Node and Menu Illustration ========================== Here is a copy of the diagram shown earlier that illustrates a Texinfo file with three chapters, each of which contains two sections. Note that the "root" is at the top of the diagram and the "leaves" are at the bottom. This is how such a diagram is drawn conventionally; it illustrates an upside-down tree. For this reason, the root node is called the `Top' node, and `Up' node pointers carry you closer to the root. Top | ------------------------------------- | | | Chapter 1 Chapter 2 Chapter 3 | | | -------- -------- -------- | | | | | | Section Section Section Section Section Section 1.1 1.2 2.1 2.2 3.1 3.2 Write the beginning of the node for Chapter 2 like this: @node Chapter 2, Chapter 3, Chapter 1, top @comment node-name, next, previous, up This `@node' line says that the name of this node is "Chapter 2", the name of the `Next' node is "Chapter 3", the name of the `Previous' node is "Chapter 1", and the name of the `Up' node is "Top". *Please Note:* `Next' refers to the next node at the same hierarchical level in the manual, not necessarily to the next node within the Texinfo file. In the Texinfo file, the subsequent node may be at a lower level--a section-level node may follow a chapter-level node, and a subsection-level node may follow a section-level node. `Next' and `Previous' refer to nodes at the *same* hierarchical level. To go to Sections 2.1 and 2.2 using Info, you need a menu inside Chapter 2. (*Note Menus::.) You would write the menu just before the beginning of Section 2.1, like this: @menu * Sect. 2.1:: Description of this section. * Sect. 2.2:: @end menu Write the node for Sect. 2.1 like this: @node Sect. 2.1, Sect. 2.2, Chapter 2, Chapter 2 @comment node-name, next, previous, up In Info format, the `Next' and `Previous' pointers of a node usually lead to other nodes at the same level--from chapter to chapter or from section to section (sometimes, as shown, the `Previous' pointer points up); an `Up' pointer usually leads to a node at the level above (closer to the `Top' node); and a `Menu' leads to nodes at a level below (closer to `leaves'). (A cross reference can point to a node at any level; see *Note Cross References::.) Usually, an `@node' command and a chapter structuring command are used in sequence, along with indexing commands. (You may follow the `@node' line with a comment line that reminds you which pointer is which.) Here is the beginning of the chapter in this manual called "Ending a Texinfo File". This shows an `@node' line followed by a comment line, an `@chapter' line, and then by indexing lines. @node Ending a File, Structuring, Beginning a File, Top @comment node-name, next, previous, up @chapter Ending a Texinfo File @cindex Ending a Texinfo file @cindex Texinfo file ending @cindex File ending File: texinfo, Node: node, Next: makeinfo Pointer Creation, Prev: Node Menu Illustration, Up: Nodes The `@node' Command =================== A "node" is a segment of text that begins at an `@node' command and continues until the next `@node' command. The definition of node is different from that for chapter or section. A chapter may contain sections and a section may contain subsections; but a node cannot contain subnodes; the text of a node continues only until the next `@node' command in the file. A node usually contains only one chapter structuring command, the one that follows the `@node' line. On the other hand, in printed output nodes are used only for cross references, so a chapter or section may contain any number of nodes. Indeed, a chapter usually contains several nodes, one for each section, subsection, and subsubsection. To create a node, write an `@node' command at the beginning of a line, and follow it with four arguments, separated by commas, on the rest of the same line. These arguments are the name of the node, and the names of the `Next', `Previous', and `Up' pointers, in that order. You may insert spaces before each pointer if you wish; the spaces are ignored. You must write the name of the node, and the names of the `Next', `Previous', and `Up' pointers, all on the same line. Otherwise, the formatters fail. (*note info: (info)Top, for more information about nodes in Info.) Usually, you write one of the chapter-structuring command lines immediately after an `@node' line--for example, an `@section' or `@subsection' line. (*Note Types of Structuring Command: Structuring Command Types.) *Please note:* The GNU Emacs Texinfo mode updating commands work only with Texinfo files in which `@node' lines are followed by chapter structuring lines. *Note Updating Requirements::. TeX uses `@node' lines to identify the names to use for cross references. For this reason, you must write `@node' lines in a Texinfo file that you intend to format for printing, even if you do not intend to format it for Info. (Cross references, such as the one at the end of this sentence, are made with `@xref' and its related commands; see *Note Cross References::.) * Menu: * Node Names:: How to choose node and pointer names. * Writing a Node:: How to write an `@node' line. * Node Line Tips:: Keep names short. * Node Line Requirements:: Keep names unique, without @-commands. * First Node:: How to write a `Top' node. * makeinfo top command:: How to use the `@top' command. * Top Node Summary:: Write a brief description for readers. File: texinfo, Node: Node Names, Next: Writing a Node, Up: node Choosing Node and Pointer Names ------------------------------- The name of a node identifies the node. The pointers enable you to reach other nodes and consist of the names of those nodes. Normally, a node's `Up' pointer contains the name of the node whose menu mentions that node. The node's `Next' pointer contains the name of the node that follows that node in that menu and its `Previous' pointer contains the name of the node that precedes it in that menu. When a node's `Previous' node is the same as its `Up' node, both node pointers name the same node. Usually, the first node of a Texinfo file is the `Top' node, and its `Up' and `Previous' pointers point to the `dir' file, which contains the main menu for all of Info. The `Top' node itself contains the main or master menu for the manual. Also, it is helpful to include a brief description of the manual in the `Top' node. *Note First Node::, for information on how to write the first node of a Texinfo file. File: texinfo, Node: Writing a Node, Next: Node Line Tips, Prev: Node Names, Up: node How to Write an `@node' Line ---------------------------- The easiest way to write an `@node' line is to write `@node' at the beginning of a line and then the name of the node, like this: @node NODE-NAME If you are using GNU Emacs, you can use the update node commands provided by Texinfo mode to insert the names of the pointers; or you can leave the pointers out of the Texinfo file and let `makeinfo' insert node pointers into the Info file it creates. (*Note Texinfo Mode::, and *Note makeinfo Pointer Creation::.) Alternatively, you can insert the `Next', `Previous', and `Up' pointers yourself. If you do this, you may find it helpful to use the Texinfo mode keyboard command `C-c C-c n'. This command inserts `@node' and a comment line listing the names of the pointers in their proper order. The comment line helps you keep track of which arguments are for which pointers. This comment line is especially useful if you are not familiar with Texinfo. The template for a node line with `Next', `Previous', and `Up' pointers looks like this: @node NODE-NAME, NEXT, PREVIOUS, UP If you wish, you can ignore `@node' lines altogether in your first draft and then use the `texinfo-insert-node-lines' command to create `@node' lines for you. However, we do not recommend this practice. It is better to name the node itself at the same time that you write a segment so you can easily make cross references. A large number of cross references are an especially important feature of a good Info file. After you have inserted an `@node' line, you should immediately write an @-command for the chapter or section and insert its name. Next (and this is important!), put in several index entries. Usually, you will find at least two and often as many as four or five ways of referring to the node in the index. Use them all. This will make it much easier for people to find the node. File: texinfo, Node: Node Line Tips, Next: Node Line Requirements, Prev: Writing a Node, Up: node `@node' Line Tips ----------------- Here are three suggestions: * Try to pick node names that are informative but short. In the Info file, the file name, node name, and pointer names are all inserted on one line, which may run into the right edge of the window. (This does not cause a problem with Info, but is ugly.) * Try to pick node names that differ from each other near the beginnings of their names. This way, it is easy to use automatic name completion in Info. * By convention, node names are capitalized just as they would be for section or chapter titles--initial and significant words are capitalized; others are not. File: texinfo, Node: Node Line Requirements, Next: First Node, Prev: Node Line Tips, Up: node `@node' Line Requirements ------------------------- Here are several requirements for `@node' lines: * All the node names for a single Info file must be unique. Duplicates confuse the Info movement commands. This means, for example, that if you end every chapter with a summary, you must name each summary node differently. You cannot just call each one "Summary". You may, however, duplicate the titles of chapters, sections, and the like. Thus you can end each chapter in a book with a section called "Summary", so long as the node names for those sections are all different. * A pointer name must be the name of a node. The node to which a pointer points may come before or after the node containing the pointer. * You cannot use any of the Texinfo @-commands in a node name; @-commands confuse Info. Thus, the beginning of the section called `@chapter' looks like this: @node chapter, unnumbered & appendix, makeinfo top, Structuring @comment node-name, next, previous, up @section @code{@@chapter} @findex chapter * You cannot use commas, colons, or apostrophes within a node name; these confuse TeX or the Info formatters. For example, the following is a section title: @code{@@unnumberedsec}, @code{@@appendixsec}, @code{@@heading} The corresponding node name is: unnumberedsec appendixsec heading File: texinfo, Node: First Node, Next: makeinfo top command, Prev: Node Line Requirements, Up: node The First Node -------------- The first node of a Texinfo file is the `Top' node, except in an included file (*note Include Files::.). The `Top' node (which must be named `top' or `Top') should have as its `Up' and `Previous' nodes the name of a node in another file, where there is a menu that leads to this file. Specify the file name in parentheses. If the file is to be installed directly in the Info directory file, use `(dir)' as the parent of the `Top' node; this is short for `(dir)top', and specifies the `Top' node in the `dir' file, which contains the main menu for Info. For example, the `@node Top' line of this manual looks like this: @node Top, Overview, (dir), (dir) (You may use the Texinfo updating commands or the `makeinfo' utility to insert these `Next' and `(dir)' pointers automatically.) *Note Install an Info File::, for more information about installing an Info file in the `info' directory. The `Top' node contains the main or master menu for the document.