word">namespace</span> <span class="identifier">bgi</span> <span class="special">=</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">geometry</span><span class="special">::</span><span class="identifier">index</span><span class="special">;</span>

<span class="comment">// Define a function object converting a value_type of indexed Range into std::pair&lt;&gt;.</span>
<span class="comment">// This is a generic implementation but of course it'd be possible to 