n class="identifier">distinct</span><span class="special">(</span><span class="identifier">tail</span><span class="special">);</span>
<span class="special">}</span>

<span class="comment">// Define a helper function allowing to create a ascii::char_() construct </span>
<span class="comment">// from an arbitrary string representation</span>
<span class="keyword">template</span> <span class="special">&lt;</span><span class="keyword">typename</span> <span class="identifier">String</span><span class="special">&