span class="special">{</span> <span class="keyword">return</span> <span class="identifier">v</span><span class="special">.</span><span class="identifier">is_red</span><span class="special">();</span> <span class="special">}</span>
<span class="special">}</span>

<span class="comment">// ...</span>

<span class="identifier">rt</span><span class="special">.</span><span class="identifier">query</span><span class="special">(</span><span class="identifier">index</span><span class="special">::</span><span class="