 [ &quot;CONTEXT&quot; &quot;(&quot; TokenExpr &quot;)&quot; ] .
   TokenFactor =   SetIdent | string
                 | &quot;(&quot; TokenExpr &quot;)&quot; |  &quot;[&quot; TokenExpr &quot;]&quot; | &quot;{&quot; TokenExpr &quot;}&quot; .
   TokenSymbol = TokenIdent | string .
   TokenIdent  = ident .
</PRE>

<P>Tokens may be declared in any order.  A token declaration defines a
<I>TokenSymbol</I> together with its structure. Usually the symbol on the left-hand
side of the declaration is an identifier, w