Input . Input ::= [Data] ;

D . Data ::= "{" [TokD] "}" ;
T . TokD ::= "(" String "," [Pattern] ")" ;

PC  . Pattern ::= Ident [Pattern1] ;
Id  . Pattern1 ::= Ident ;

coercions Pattern 1;

separator Data "" ;
separator TokD "" ;
separator nonempty Pattern1 "" ;
separator Pattern "|" ;