an><span class="special">(</span><span class="identifier">T</span> <span class="keyword">const</span> <span class="special">&amp;</span> t<span class="special">)</span><span class="special">;</span></pre></div>
<div class="refsect1">
<a name="id-1.3.33.5.41.74.4"></a><h2>Description</h2>
<p>
            The <code class="computeroutput">proto::as_child()</code> function returns Proto expression
            objects that are suitable for storage as child nodes in an expression tree. It turns
            non-Pr