keyword">template</span><span class="special">&lt;</span><span class="keyword">typename</span> Functor<span class="special">&gt;</span> 
<span class="keyword">struct</span> <a class="link" href="is_negative.html" title="Struct template is_negative">is_negative</a> <span class="special">{</span>
  <span class="comment">// types</span>
  <span class="keyword">typedef</span> <a class="link" href="is_negative.html" title="Struct template is_negative">is_negative</a><span class="special">&lt;</span> <span class=