keyword">typedef</span> <span class="identifier">Subject</span> <span class="identifier">subject_type</span><span class="special">;</span>

    <span class="keyword">template</span> <span class="special">&lt;</span><span class="keyword">typename</span> <span class="identifier">Context</span><span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">Iterator</span><span class="special">&gt;</span>
    <span class="keyword">struct</span> <span class="identifier">attribute</s