ws control of the parser from within semantic actions to
a certain degree. A <I>Designator</I>, for example, can be processed in the
following way: </P>

<PRE>   Designator &lt;^Item x&gt; =
     Qualident &lt;^x&gt;
     {                        (. if (...x is a procedure...) return; .)
       &quot;(&quot; Qualident &lt;^y&gt; &quot;)&quot; (. ... process type guard ... .)
     | ...
     } .
</PRE>

<P>When an opening bracket is seen after a <I>Qualident</I>, the alternative
starting with an opening brac