Prog. Program ::= [Decl];

Def.   Decl ::= Ident "=" Expr;
Const. Decl ::= Ident;
terminator Decl ";";

Lam. Expr  ::= "\\" Ident "->" Expr;
App. Expr1 ::= Expr1 Expr2;
Var. Expr2 ::= Ident;
coercions Expr 2;

comment "--";