n class="special">&lt;</span><span class="identifier">BidirectionalIterator</span><span class="special">&gt;::</span><span class="identifier">value_type</span><span class="special">,</span>
         <span class="keyword">class</span> <span class="identifier">traits</span> <span class="special">=</span> <span class="identifier">regex_traits</span><span class="special">&lt;</span><span class="identifier">charT</span><span class="special">&gt;</span> <span class="special">&gt;</span>
<span class="keyword">clas