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<span id="Def-Cmd-Template"></span><div class="header">
<p>
Next: <a href="Def-Cmd-Continuation-Lines.html" accesskey="n" rel="next">Def Cmd Continuation Lines</a>, Up: <a href="Definition-Commands.html" accesskey="u" rel="up">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>
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<hr>
<span id="The-Template-for-a-Definition"></span><h3 class="section">14.1 The Template for a Definition</h3>
<span id="index-Definition-template"></span>
<span id="index-Template-for-a-definition"></span>
<p>The <code>@deffn</code> command is used for definitions of entities that
resemble functions. To write a definition using the <code>@deffn</code>
command, write the <code>@deffn</code> 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</code> command
written on a line of its own.
</p>
<p>The other definition commands follow the same format: a line with the
<code>@def…</code> command and whatever arguments are appropriate for
that command; the body of the definition; and a corresponding
<code>@end</code> line.
</p>
<p>The template for a definition looks like this:
</p>
<div class="example">
<pre class="example">@deffn <var>category</var> <var>name</var> <var>arguments</var>…
<var>body-of-definition</var>
@end deffn
</pre></div>
<p>For example,
</p>
<div class="example">
<pre class="example">@deffn Command forward-word count
This command moves point forward @var{count} words
(or backward if @var{count} is negative). …
@end deffn
</pre></div>
<p>produces
</p>
<blockquote>
<dl>
<dt id="index-forward_002dword">Command: <strong>forward-word</strong> <em>count</em></dt>
<dd><p>This command moves point forward <var>count</var> words
(or backward if <var>count</var> is negative). …
</p></dd></dl>
</blockquote>
<p>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:
</p>
<div class="example">
<pre class="example">@deffn {Interactive Command} isearch-forward
…
@end deffn
</pre></div>
<p>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 <em>except</em> 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}</samp>’ if you are
writing in Spanish.
</p>
<p>Some of the definition commands are more general than others. The
<code>@deffn</code> 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>, <code>@defmac</code>, and <code>@defspec</code>) 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</code> command is
accompanied by several specialized variations for describing
particular kinds of variables.
</p>
<p>See <a href="Sample-Function-Definition.html">Sample Function Definition</a>, for a detailed example of a
function definition, including the use of <code>@example</code> inside the
definition.
</p>
<hr>
<div class="header">
<p>
Next: <a href="Def-Cmd-Continuation-Lines.html" accesskey="n" rel="next">Def Cmd Continuation Lines</a>, Up: <a href="Definition-Commands.html" accesskey="u" rel="up">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>
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