to get the type of any ascii::char_(...) construct</span>
    <span class="keyword">template</span> <span class="special">&lt;</span><span class="keyword">typename</span> <span class="identifier">String</span><span class="special">&gt;</span>
    <span class="keyword">struct</span> <span class="identifier">char_spec</span>
      <span class="special">:</span> <span class="identifier">spirit</span><span class="special">::</span><span class="identifier">result_of</span><span class="special">::</span><span cla