* - Is valid in the given pred
* - Expects an environment compatible with the first record
* - Modifies it according to the second record *)
+
+ | TError
+ (* Marker that something already went wrong, so don't generate further
+ * error messages. *)
+ | TUnif of string * typ option ref
+ (* Unification variable to be determined during type-checking *)
withtype typ = typ' * position
and record = typ StringMap.map
| EList of exp list
(* Basic list constructor *)
- | ELam of string * typ * exp
+ | ELam of string * typ option * exp
(* Function abstraction *)
| EVar of string
(* Variable bound by a function *)