><span class="special">,</span><span class="keyword">int</span><span class="special">&gt;&gt;::</span><span class="identifier">pull_type</span><span class="special">&amp;</span> <span class="identifier">source</span><span class="special">){</span>
        <span class="comment">// access tuple {7,11}; x==7 y==1</span>
        <span class="keyword">int</span> <span class="identifier">x</span><span class="special">,</span><span class="identifier">y</span><span class="special">;</span>
        <span class="iden