dentifier">QRing</span><span class="special">&amp;</span> <span class="identifier">r</span><span class="special">)</span>
<span class="special">{</span><span class="keyword">return</span> <span class="identifier">RingIterator</span><span class="special">(</span><span class="identifier">r</span><span class="special">.</span><span class="identifier">lines</span><span class="special">.</span><span class="identifier">end</span><span class="special">());}</span>

<span class="keyword">inline</span> <span class="