sed token. The field
<I>t</I> is the lookahead token that has already been obtained from the
scanner but not yet parsed. In a semantic action, <I>token</I> refers to the
token immediately before the action commences, and <I>t</I> to the token
immediately visible after the action. </P>

<P>The other methods represent extensions to the original implementation, and
have been provided for convenience, particularly for programmers familiar with
the C, Pascal and Modula versions of Coco/R.  These methods provide 