="special">&gt;</span>
   <span class="identifier">const_reference</span> <a class="link" href="match_results.html#boost_regex.match_results.subscript">operator[]</a><span class="special">(</span><span class="keyword">const</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">basic_string</span><span class="special">&lt;</span><span class="identifier">char_type</span><span class="special">,</span> <span class="identifier">Traits</span><span class="special">,</spa