/tt> instance variable.  
In the case of non-terminals these replace a series
of <tt>Symbol</tt> objects on the parse stack whenever the right hand side of
some production is recognized.  In order to tell the parser which object
types should be used for which symbol, <tt>terminal</tt> and 
<tt>non terminal</tt> declarations are used.  These take the forms:

<pre><tt>    terminal <i>classname</i> <i>name1, name2,</i> ...;</tt>
<tt>    non terminal <i>classname</i> <i>name1, name2,</i> ...;</tt>
<tt>    termi