ord">typename</span> <span class="identifier">Visitor</span><span class="special">::</span><span class="identifier">result_type</span> 
  <span class="identifier">apply_visitor</span><span class="special">(</span><span class="identifier">Visitor</span> <span class="special">&amp;</span> visitor<span class="special">,</span> <span class="identifier">Variant</span><span class="special">&amp;&amp;</span> operand<span class="special">)</span><span class="special">;</span>
<span class="keyword">template</span><s