<span class="identifier">base</span><span class="special">()</span> <span class="keyword">const</span><span class="special">;</span>
 <span class="keyword">protected</span><span class="special">:</span>
    <span class="keyword">typedef</span> <span class="identifier">iterator_adaptor</span> <span class="identifier">iterator_adaptor</span><span class="special">\</span><span class="identifier">_</span><span class="special">;</span>
    <span class="identifier">Base</span> <span class="keyword">const</span><s