an class="identifier">demo</span>
<span class="special">{</span>
    <span class="keyword">int</span> <span class="identifier">foo</span><span class="special">()</span>
    <span class="special">{</span>
        <span class="keyword">return</span> <span class="number">42</span><span class="special">;</span>
    <span class="special">}</span>
<span class="special">}</span>

<span class="identifier">BOOST_PHOENIX_ADAPT_FUNCTION_NULLARY</span><span class="special">(</span><span class="keyword">int</span><span 