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<title>cl:multiple-value-call</title>
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<hr>
<h1>cl:multiple-value-call</h1>
<hr>
<p>The <nobr>cl:<b>multiple-value-call</b></nobr> macro applies a function
to a list of return values:</p>
<p><div class="box">
<dl>
<dt>(cl:<b>multiple-value-call</b> <i>function</i> [<i>expr1</i> ...])</dt>
<dd><i>function</i> - a Lisp expression evaluating to a function call<br>
<i>exprN</i> - arbitrary Lisp expressions<br>
returns - the values returned by the function</dd>
</dl>
</div></p>
<pre class="example">
(defmacro <font color="#0000CC">cl:multiple-value-call</font> (function &rest exprs)
(let (args)
(dolist (expr exprs)
(setq <font color="#AA5500">cl:*multiple-values*</font> nil)
(let* ((result (eval expr)))
(if <font color="#AA5500">cl:*multiple-values*</font>
(dolist (rslt <font color="#AA5500">*rslt*</font>) (push rslt args))
(push result args))))
(setq args (reverse args))
`(progn
(setq <font color="#AA5500">cl:*multiple-values*</font> nil)
(apply ,function ',args)))
</pre>
<p>The <nobr>cl:<b>multiple-value-call</b></nobr> macro first evaluates the
expressions and collects all return values in a single list, then the
'function' form is evaluated and the resulting function call is applied to
the list of values.</p>
<p>Before applying the function to the list of values the
<nobr><a href="global-multiple-values.htm">cl:*multiple-values*</a></nobr>
variable is set to <a href="../../reference/nil.htm">NIL</a>, the final value of
<nobr><a href="global-multiple-values.htm">cl:*multiple-values*</a></nobr>
depends on the 'function' argument.</p>
<p>Examples:</p>
<pre class="example">
> (funcall #'+
(cl:values 1 2)
(cl:values 3 4))
4 <font color="#008844">; (apply #'+ (1 3))</font>
> (cl:multiple-value-call #'+
(cl:values 1 2)
(cl:values 3 4))
10 <font color="#008844">; (apply #'+ (1 2 3 4))</font>
</pre>
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