cumentation.</td>
  </tr>
</table>
<p>This setup gives a good balance. The subrules do all the work. Each grammar 
  will have only one rule: <tt>first</tt>. The rule is used just to hold the subrules 
  and make them visible to the grammar. </p>
<h3>The subrule definition</h3>
<p>Like the rule, the expression after assignment operator <tt>=</tt> defines
  the subrule:</p>
<pre>    <span class=identifier>identifier </span><span class=special>= </span><span class=identifier>expression</span></pre>
<p>Unlike 