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<html><head><title>XLISP return-from</title>
<link rel="stylesheet" type="text/css" href="reference.css">
</head>
<body>
<a href="../start.htm">Nyquist / XLISP 2.0</a> -
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<a href="../examples/examples.htm">Examples</a> |
<a href="reference-index.htm">Reference</a>
<hr>
<h1>return-from</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-from <i>name</i> [<i>expr</i>])</dt>
<dd><i>name</i> - an unevaluated symbol for the block name<br>
<i>expr</i> - an expression<br>
returns - never returns</dd>
</dl>
<h2>Description</h2>
<p>The 'return-from' special form allows the return of an arbitrary value at
arbitrary times within a 'named-<a href="block.htm">block</a>'
construct of the specified 'name'. The 'expr' will be returned by the
<a href="block.htm">block</a> construct. A
<a href="nil.htm">NIL</a> will be returned by the <a
href="block.htm">block</a> construct if there is no 'expr'
specified.</p>
<p>If 'return-from' is used without being within a valid
<a href="block.htm">block</a> 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">
(block out <font color="#008844">; outer BLOCK</font>
(print "outer")
(block in <font color="#008844">; inner BLOCK</font>
(print "inner")
(return-from out "all done")
(print "won't get here"))) <font color="#008844">; prints "outer"</font>
<font color="#008844">; prints "inner"</font>
<font color="#008844">; returns "all done"</font>
(return-from nobody 9) <font color="#008844">; error: no target for RETURN</font>
</pre>
<p>See the
<a href="../manual/xlisp-man-021.htm#return-from">return-from</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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