fier">indexed</span><span class="special">()</span>
                    <span class="special">|</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">adaptors</span><span class="special">::</span><span class="identifier">transformed</span><span class="special">(</span><span class="identifier">pair_maker</span><span class="special">&lt;</span><span class="identifier">box</span><span class="special">,</span> <span class="identifier">size_type</span><span class="sp