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<title>cl:multiple-value-prog1</title>
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<a href="../../start.htm">Nyquist / XLISP 2.0</a> -
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<hr>
<h1>cl:multiple-value-prog1</h1>
<hr>
<p>The <nobr>cl:<b>multiple-value-prog1</b></nobr> macro is like
<a href="../../reference/prog1.htm">prog1</a>, but it can handle multiple
values:</p>
<p><div class="box">
<dl>
<dt>(cl:<b>multiple-value-prog1</b> <i>expr1</i> [<i>expr2</i> ...])</dt>
<dd><i>exprN</i> - arbitrary Lisp expressions<br>
returns - the values returned by the first expression</dd>
</dl>
</div></p>
<pre class="example">
(defmacro <font color="#0000CC">cl:multiple-value-prog1</font> (expr &rest body)
(setq <font color="#AA5500">cl:*multiple-values*</font> nil)
(let* ((result (eval expr)))
(if <font color="#AA5500">cl:*multiple-values*</font>
`(progn ,@body
(setq <font color="#AA5500">*rslt*</font> ',<font color="#AA5500">*rslt*</font>
<font color="#AA5500">cl:*multiple-values*</font> t)
',result)
`(progn ,@body ',result))))
</pre>
<p>The <nobr>cl:<b>multiple-value-prog1</b></nobr> macro evaluates the first
expression and saves all the values returned by the evaluation. <nobr>It
then</nobr> evaluates each of the following expressions from left to right,
discarding their values. After the evaluation is finished, the
<nobr><a href="global-multiple-values.htm">cl:*multiple-values*</a></nobr>
and <a href="../../reference/global-rslt.htm">*rslt*</a> variables are
restored and the primary value from evaluating the fist expression is
returned.</p>
<p><nobr>The
<a href="global-multiple-values.htm">cl:*multiple-values*</a></nobr>
variable <nobr>is <a href="../../reference/t.htm"> T </a></nobr>
if evaluating the first expression returns multiple values and
<a href="../../reference/nil.htm">NIL</a> with a normal return value.</p>
<p><nobr> <a href="#top">Back to top</a></nobr></p>
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