> module Paren1 where
> import Result
>
> %{
>
> Terminal                      =  '(' | ')';
>
> Nonterminal                   =  paren;
>
> paren                         :  ;
> paren                         :  paren, '(', paren, ')';
>
> }%
>
> frown _                       =  fail "syntax error"