pan class="keyword">using</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">spirit</span><span class="special">::</span><span class="identifier">karma</span><span class="special">::</span><span class="identifier">rule</span><span class="special">;</span>
</pre>
<p>
          </p>
<p>
            Basic grammar usage:
          </p>
<p>
</p>
<pre class="programlisting"><span class="keyword">struct</span> <span class="identifier">num_list</span> <span class="sp