call&lt;&gt;</a></code>
            and the later with <code class="computeroutput"><a class="link" href="make.html" title="Struct template make">proto::make&lt;&gt;</a></code>.
            If <code class="computeroutput">proto::is_callable&lt;R&gt;::value</code> is <code class="computeroutput">true</code>,
            the function type is a <a class="link" href="../../CallableTransform.html" title="Concept CallableTransform">CallableTransform</a>; otherwise, it is an <a class="link" href="../../ObjectTrans