cation. These actions are C++ functions or functors
      that are called whenever a part of the parser successfully recognizes a
      portion of the input. Say you have a parser <b>P</b>, and a C++ function
      <b>F</b>, you can make the parser call <b>F</b> whenever it matches an
      input by attaching <b>F</b>:
    </p>
    
<pre><code><font color="#000000">    </font></code><code><font color="#000000"><span class=
"identifier">P</span><span class="special">[&amp;</span><span class=
"identifier">F</