><span class="p">,</span> <span class="k">auto</span> <span class="n">y</span><span class="p">)</span>
        <span class="p">{</span>
            <span class="k">return</span> <span class="n">x</span> <span class="o">+</span> <span class="n">y</span><span class="p">;</span>
        <span class="p">};</span>
    <span class="p">}</span>
<span class="p">}</span>

<span class="n">BOOST_HOF_STATIC_FUNCTION</span><span class="p">(</span><span class="n">sum</span><span class="p">)</span> <span class="o">=</span