span class="identifier">type</span><span class="special">&gt;</span> 
<span class="keyword">struct</span> <a class="link" href="plus.html" title="Struct template plus">plus</a> <span class="special">:</span>
  <span class="keyword">public</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">numeric</span><span class="special">::</span><span class="identifier">functional</span><span class="special">::</span><span class="identifier">plus_base</span><span class="s