hich is then used in other parts of
the grammar to denote the structure described on the right-hand side of the
declaration by a regular expression (expressed in EBNF).  This
<I>TokenExpr</I> may contain literals denoting themselves (for example
&quot;<TT>END</TT>&quot;), or the names of character sets (for example <tt>digit</tt>),
denoting an arbitrary character from such sets.  The restriction to regular
expressions means that it may not contain the names of any other tokens.</P>

<P>While token specifica