passed (the generator context
          and a reference to a boolean 'pass' parameter). We don't need these, for
          now, but we'll see more on these other arguments later. <span class="emphasis"><em>Spirit.Karma</em></span>
          allows us to bind a single argument function, like above. The other arguments
          are simply ignored.
        </p>
<p>
          To sum up, the possible signatures for semantic actions are:
        </p>
<pre class="programlisting"><span class="keyword">void</span> 