sions by value; and, in the case of objects that are not yet Proto expressions,
              to wrap them by value (if possible) in a new Proto terminal expression. (Contrast
              this description with the description for
              <code class="computeroutput"><a class="link" href="as_child.html" title="Struct template as_child">proto::domain::as_child</a></code>.)
            </p>
<p>
              The <code class="computeroutput">as_expr</code> function object turns objects into
            