="special">&lt;&lt;</span> <span class="identifier">double_</span><span class="special">),</span>   <span class="comment">// the generator</span>
        <span class="identifier">space</span><span class="special">,</span>                          <span class="comment">// the delimiter-generator</span>
        <span class="identifier">v</span>                               <span class="comment">// the data to output </span>
    <span class="special">);</span>
    <span class="keyword">return</span> <span cla