"identifier">apply_visitor</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">MultiVisitor</span> <span class="special">&amp;</span> visitor<span class="special">,</span> <span class="identifier">Variant1</span><span class="special">&amp;&amp;</span> operand1<span class="special">,</span> 
                <span class="identifier">Variant2</span><span class="special">&amp;&amp;</span> operand2<span class="special">,</span> <span class="identifier">Variant3</span><