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| <div class="subsection-level-extent" id="Functions-Commands"> |
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| <p> |
| Next: <a href="Variables-Commands.html" accesskey="n" rel="next">Variables and Similar Entities</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> |
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| <h4 class="subsection" id="Functions-and-Similar-Entities">13.5.1 Functions and Similar Entities</h4> |
| |
| <p>This section describes the commands for describing functions and similar |
| entities: |
| </p> |
| <dl class="table"> |
| <dd><a class="index-entry-id" id="index-deffn"></a> |
| </dd> |
| <dt><code class="code">@deffn <var class="var">category</var> <var class="var">name</var> <var class="var">arguments</var>…</code></dt> |
| <dd><p>The <code class="code">@deffn</code> 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 class="code">@deffn</code> 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 class="code">@end deffn</code> on a line of its |
| own. |
| </p> |
| <p>For example, here is a definition: |
| </p> |
| <div class="example"> |
| <div class="group"><pre class="example-preformatted">@deffn Command forward-char nchars |
| Move point forward @var{nchars} characters. |
| @end deffn |
| </pre></div></div> |
| |
| <p>This shows a rather terse definition for a “command” named |
| <code class="code">forward-char</code> with one argument, <var class="var">nchars</var>. |
| </p> |
| <p><code class="code">@deffn</code> prints argument names such as <var class="var">nchars</var> 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 class="code">@var</code> to refer to the value of the argument. |
| In the example above, we used ‘<samp class="samp">@var{nchars}</samp>’ in this way. |
| </p> |
| <p>In the extremely unusual case when an argument name contains |
| ‘<samp class="samp">--</samp>’, or another character sequence which is treated specially |
| (see <a class="pxref" href="Conventions.html">General Syntactic Conventions</a>), use <code class="code">@code</code> around the special |
| characters. This avoids the conversion to typographic en-dashes and |
| em-dashes. |
| </p> |
| <p>The template for <code class="code">@deffn</code> is: |
| </p> |
| <div class="example"> |
| <div class="group"><pre class="example-preformatted">@deffn <var class="var">category</var> <var class="var">name</var> <var class="var">arguments</var>… |
| <var class="var">body-of-definition</var> |
| @end deffn |
| </pre></div></div> |
| |
| <a class="index-entry-id" id="index-defun"></a> |
| </dd> |
| <dt><code class="code">@defun <var class="var">name</var> <var class="var">arguments</var>…</code></dt> |
| <dd><p>The <code class="code">@defun</code> command is the definition command for functions. |
| <code class="code">@defun</code> is equivalent to ‘<samp class="samp">@deffn Function …</samp>’. |
| Terminate the definition with <code class="code">@end defun</code> on a line of its own. |
| Thus, the template is: |
| </p> |
| <div class="example"> |
| <div class="group"><pre class="example-preformatted">@defun <var class="var">function-name</var> <var class="var">arguments</var>… |
| <var class="var">body-of-definition</var> |
| @end defun |
| </pre></div></div> |
| |
| <a class="index-entry-id" id="index-defmac"></a> |
| </dd> |
| <dt><code class="code">@defmac <var class="var">name</var> <var class="var">arguments</var>…</code></dt> |
| <dd><p>The <code class="code">@defmac</code> command is the definition command for macros. |
| <code class="code">@defmac</code> is equivalent to ‘<samp class="samp">@deffn Macro …</samp>’ and |
| works like <code class="code">@defun</code>. |
| </p> |
| <a class="index-entry-id" id="index-defspec"></a> |
| </dd> |
| <dt><code class="code">@defspec <var class="var">name</var> <var class="var">arguments</var>…</code></dt> |
| <dd><p>The <code class="code">@defspec</code> command is the definition command for special |
| forms. (In Lisp, a special form is an entity much like a function; |
| see <a data-manual="elisp" href="https://www.gnu.org/software/emacs/manual/html_node/elisp/Special-Forms.html#Special-Forms">Special Forms</a> in <cite class="cite">GNU Emacs Lisp Reference Manual</cite>.) |
| <code class="code">@defspec</code> is equivalent to ‘<samp class="samp">@deffn {Special Form} |
| …</samp>’ and works like <code class="code">@defun</code>. |
| </p></dd> |
| </dl> |
| |
| <p>All these commands create entries in the index of functions. |
| </p> |
| |
| </div> |
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| Next: <a href="Variables-Commands.html">Variables and Similar Entities</a>, Up: <a href="Def-Cmds-in-Detail.html">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> |
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