tifier>value</span><span class=special>(</span><span class="identifier">T </span><span class="keyword">const</span><span class=special>&amp;) </span><span class=keyword>const;
        </span><span class=identifier>T </span><span class=keyword>const</span><span class=special>&amp;    </span><span class=identifier>value</span><span class=special>();
</span><span class=keyword>    </span><span class=special>};</span></pre>
<h2>match_result</h2>
<p>It has been mentioned repeatedly that the parser returns a matc