ass="identifier">traits</span><span class="special">::</span><span class="identifier">distinct_spec</span><span class="special">&lt;</span><span class="identifier">charset_tag_type</span><span class="special">&gt;::</span><span class="identifier">type</span> <span class="identifier">keyword_tag_type</span><span class="special">;</span>

<span class="comment">// Define a new Qi 'keyword' directive usable as a shortcut for a</span>
<span class="comment">// repository::distinct(char_(std::string("0-9a-zA-Z_"))