span class="comment">//</span>
   <span class="keyword">typedef</span> <span class="keyword">typename</span> <span class="identifier">policies</span><span class="special">::</span><span class="identifier">evaluation</span><span class="special">&lt;</span><span class="identifier">result_type</span><span class="special">,</span> <span class="identifier">Policy</span><span class="special">&gt;::</span><span class="identifier">type</span> <span class="identifier">value_type</span><span class="special">;</span>
