Program. Program ::= [Bind] ;

Bind. Bind ::= Ident [Ident] "=" Exp ;

EAnn.   Exp5 ::= "(" Exp ":" Type ")" ;
EId.    Exp4 ::= Ident ;
EConst. Exp4 ::= Const ;
EApp.   Exp3 ::= Exp3 Exp4 ;
EAdd.   Exp1 ::= Exp1 "+" Exp2 ;
ELet.   Exp ::= "let" Ident "=" Exp "in" Exp ; 
EAbs.   Exp  ::= "\\" Ident "." Exp ;

CInt. Const ::= Integer ;
CStr. Const ::= String ;

TMono. Type1 ::= "Mono" Ident ;
TPoly. Type1 ::= "Poly" Ident ;
TArrow. Type ::= Type1 "->" Type ;

-- This doesn't seem to work so we'll have to live with ugly keywords for now
-- token Upper (upper (letter | digit | '_')*) ;
-- token Lower (lower (letter | digit | '_')*) ;

separator Bind ";" ;
separator Ident " ";

coercions Type 1 ;
coercions Exp 5 ;

comment "--" ;
comment "{-" "-}" ;

-- Adt. Adt ::= "data" UIdent "=" [Constructor] ;
-- Sum. Constructor ::= UIdent ; 
-- separator Constructor "|" ;