terator</span> <span class="special">&gt;</span>
<span class="identifier">RandomAccessIterator</span> <span class="identifier">foo</span><span class="special">(</span><span class="identifier">RandomAccessIterator</span> <span class="identifier">from</span><span class="special">,</span>
                         <span class="identifier">RandomAccessIterator</span> <span class="identifier">to</span><span class="special">)</span>
<span class="special">{</span>
   <span class="comment">// this template can only 