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<html><head><title>XLISP return</title>
<link rel="stylesheet" type="text/css" href="reference.css">
</head>
<body>
<a href="../start.htm">Nyquist / XLISP 2.0</a> -
<a href="../manual/contents.htm">Contents</a> |
<a href="../tutorials/tutorials.htm">Tutorials</a> |
<a href="../examples/examples.htm">Examples</a> |
<a href="reference-index.htm">Reference</a>
<hr>
<h1>return</h1>
<hr>
<p><table cellpadding="0" cellspacing="0" style="margin-left:10px"><tbody>
<tr valign="top">
<td><nobr>Type:</nobr></td>
<td><nobr> - </nobr></td>
<td width="100%"><nobr>special form (fsubr)</nobr></td>
</tr>
<tr valign="top">
<td><nobr>Source:</nobr></td>
<td><nobr> - </nobr></td>
<td width="100%"><nobr>xlcont.c</nobr></td>
</tr>
</tbody></table></p>
<h2>Syntax</h2>
<dl>
<dt>(return [<i>expr</i>])</dt>
<dd><i>expr</i> - an expression<br>
returns - never returns</dd>
</dl>
<h2>Description</h2>
<p>The 'return' special form allows the return of an arbitrary value at
arbitrary times within 'block' constructs like
<nobr><a href="do.htm">do</a> ,</nobr>
<nobr><a href="do-star.htm">do*</a> ,</nobr>
<nobr><a href="dolist.htm">dolist</a> ,</nobr>
<nobr><a href="dotimes.htm">dotimes</a> ,</nobr>
<nobr><a href="loop.htm">loop</a> ,</nobr>
<a href="prog.htm">prog</a> and
<a href="prog-star.htm">prog*</a>. The 'expr' will be returned by the
outer 'block' construct. A <a href="nil.htm">NIL</a> will be
returned by the outer 'block' construct if there is no 'expr' specified.</p>
<p>If 'return' is used without being within a valid 'block' construct, an
error is generated:</p>
<pre class="example">
<font color="#AA0000">error: no target for RETURN</font>
</pre>
<h2>Examples</h2>
<pre class="example">
(prog (i) <font color="#008844">; PROG form</font>
(print i) (RETURN "foo") (print j)) <font color="#008844">; prints NIL returns "foo"</font>
(dotimes (i 10)
(if (eql i 5) (RETURN 20)
(princ i))) <font color="#008844">; prints 01234 returns 20</font>
(prog1 (print "hi") (RETURN "foo")) <font color="#008844">; prints "hi"</font>
<font color="#008844">; error: no target for RETURN</font>
(return 9) <font color="#008844">; error: no target for RETURN</font>
</pre>
<p>See the
<a href="../manual/xlisp-man-021.htm#return">return</a>
special form in the <nobr>XLISP 2.0</nobr> manual.</p>
<p><nobr> <a href="#top">Back to Top</nobr></a></p>
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