ier">This</span><span class="special">(</span><span class="identifier">ForwardIterator</span><span class="special">,</span> <span class="identifier">Distance</span><span class="special">)</span><span class="special">&gt;</span> <span class="special">{</span>
    <span class="comment">// types</span>
    <span class="keyword">typedef</span> <span class="keyword">typename</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">remove_const</span><span class="special