- print (BoolExpr b) = [toString b]
- print (FunExpr fc) = print fc
- print EmptyListExpr = ["[]"]
- print (TupleExpr (e1, e2)) = ["(":print e1] ++ [",":print e2] ++ [")"]
+ print (BoolExpr _ b) = [toString b]
+ print (FunExpr _ fc) = print fc
+ print (EmptyListExpr _) = ["[]"]
+ print (TupleExpr _ (e1, e2)) = ["(":print e1] ++ [",":print e2] ++ [")"]
+
+derive gEq Op2, Type
+instance == Op2 where (==) o1 o2 = gEq{|*|} o1 o2
+instance == Type where (==) o1 o2 = gEq{|*|} o1 o2