">::</span><span class="identifier">nfp</span><span class="special">::</span><span class="identifier">keyword</span><span class="special">&lt;</span> <span class="identifier">unique_id</span><span class="special">,</span> <span class="identifier">required</span> <span class="special">&gt;</span> <span class="special">{</span>
  <span class="comment">// types</span>
  <span class="keyword">typedef</span> <span class="identifier">unique_id</span> <a name="boost.nfp.typed_keyword.id"></a><span class="identifie