lockquote></div>
<p>
        What we want to do is to invert some arithmetic operators, i.e. plus will
        be transformed to minus, minus to plus, multiplication to division and division
        to multiplication.
      </p>
<p>
        Let's start with defining our default action:
      </p>
<pre class="programlisting"><span class="keyword">struct</span> <span class="identifier">invert_actions</span>
<span class="special">{</span>
    <span class="keyword">template</span> <span class="special">&lt;</sp