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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <!-- Created by GNU Texinfo 6.8, https://www.gnu.org/software/texinfo/ --> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> <!-- This manual is for GNU Texinfo (version 6.8, 8 June 2021), a documentation system that can produce both online information and a printed manual from a single source using semantic markup. Copyright (C) 1988, 1990-1993, 1995-1999, 2001-2021 Free Software Foundation, Inc. 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". --> <title>Data Types (GNU Texinfo 6.8)</title> <meta name="description" content="Data Types (GNU Texinfo 6.8)"> <meta name="keywords" content="Data Types (GNU Texinfo 6.8)"> <meta name="resource-type" content="document"> <meta name="distribution" content="global"> <meta name="Generator" content="texi2any"> <meta name="viewport" content="width=device-width,initial-scale=1"> <link href="index.html" rel="start" title="Top"> <link href="Command-and-Variable-Index.html" rel="index" title="Command and Variable Index"> <link href="index.html#SEC_Contents" rel="contents" title="Table of Contents"> <link href="Def-Cmds-in-Detail.html" rel="up" title="Def Cmds in Detail"> <link href="Abstract-Objects.html" rel="next" title="Abstract Objects"> <link href="Typed-Variables.html" rel="prev" title="Typed Variables"> <style type="text/css"> <!-- a.copiable-anchor {visibility: hidden; text-decoration: none; line-height: 0em} a.summary-letter {text-decoration: none} blockquote.indentedblock {margin-right: 0em} div.display {margin-left: 3.2em} div.example {margin-left: 3.2em} kbd {font-style: oblique} pre.display {font-family: inherit} pre.format {font-family: inherit} pre.menu-comment {font-family: serif} pre.menu-preformatted {font-family: serif} span.nolinebreak {white-space: nowrap} span.roman {font-family: initial; font-weight: normal} span.sansserif {font-family: sans-serif; font-weight: normal} span:hover a.copiable-anchor {visibility: visible} ul.no-bullet {list-style: none} --> </style> </head> <body lang="en"> <div class="subsection" id="Data-Types"> <div class="header"> <p> Next: <a href="Abstract-Objects.html" accesskey="n" rel="next">Object-Oriented Programming</a>, Previous: <a href="Typed-Variables.html" accesskey="p" rel="prev">Variables in Typed Languages</a>, Up: <a href="Def-Cmds-in-Detail.html" accesskey="u" rel="up">The Definition Commands</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Command-and-Variable-Index.html" title="Index" rel="index">Index</a>]</p> </div> <hr> <span id="Data-Types-1"></span><h4 class="subsection">13.5.5 Data Types</h4> <p>Here is the command for data types: </p> <dl compact="compact"> <dd><span id="index-deftp"></span> </dd> <dt><span><code>@deftp <var>category</var> <var>name</var> <var>attributes</var>…</code></span></dt> <dd><p>The <code>@deftp</code> 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</code> or <code>float</code>), and then by names of attributes of objects of that type. Thus, you could use this command for describing <code>int</code> or <code>float</code>, in which case you could use <code>data type</code> as the category. (A data type is a category of certain objects for purposes of deciding which operations can be performed on them.) </p> <p>In Lisp, for example, <em>pair</em> names a particular data type, and an object of that type has two slots called the <small>CAR</small> and the <small>CDR</small>. Here is how you would write the first line of a definition of <code>pair</code>. </p> <div class="example"> <pre class="example">@deftp {Data type} pair car cdr … @end deftp </pre></div> <p>The template is: </p> <div class="example"> <pre class="example">@deftp <var>category</var> <var>name-of-type</var> <var>attributes</var>… <var>body-of-definition</var> @end deftp </pre></div> <p><code>@deftp</code> creates an entry in the index of data types. </p></dd> </dl> </div> </body> </html>