  </p>
<p>
            This example simulates the "classic" <code class="computeroutput"><span class="identifier">if_p</span></code>
            parser. Here, <code class="computeroutput"><span class="identifier">int_</span></code> will
            be tried only if the condition, <code class="computeroutput"><span class="identifier">c</span></code>,
            is true.
          </p>
<p>
</p>
<pre class="programlisting"><span class="keyword">bool</span> <span class="identifier">c</span> <span class="specia