pan> <span class="keyword">const</span><span class="special">;</span>
<span class="special">}</span><span class="special">;</span></pre></div>
<div class="refsect1">
<a name="id-1.3.34.5.56.4.4"></a><h2>Description</h2>
<p>
              <code class="computeroutput">proto::context::callable_eval&lt;&gt;</code> requires that
              <code class="computeroutput">Context</code> is a <a class="link" href="../../../PolymorphicFunctionObject.html" title="Concept PolymorphicFunctionObject">PolymorphicFunctio