--- a/src/HOL/MiniML/W.thy Fri Dec 08 13:22:55 1995 +0100
+++ b/src/HOL/MiniML/W.thy Fri Dec 08 19:48:15 1995 +0100
@@ -9,20 +9,20 @@
W = MiniML +
types
- result_W = "(subst * type_expr * nat)maybe"
+ result_W = "(subst * typ * nat)maybe"
(* type inference algorithm W *)
consts
- W :: [expr, type_expr list, nat] => result_W
+ W :: [expr, typ list, nat] => result_W
primrec W expr
W_Var "W (Var i) a n = (if i < length a then Ok(id_subst, nth i a, n)
else Fail)"
- W_Abs "W (Abs e) a n = W e ((TVar n)#a) (Suc n) bind
- (%(s,t,m). Ok(s, Fun (s n) t, m) )"
+ W_Abs "W (Abs e) a n = ( (s,t,m) := W e ((TVar n)#a) (Suc n);
+ Ok(s, (s n) -> t, m) )"
W_App "W (App e1 e2) a n =
- W e1 a n bind
- (%(s1,t1,m1). W e2 ($ s1 a) m1 bind
- (%(s2,t2,m2). mgu ($ s2 t1) (Fun t2 (TVar m2)) bind
- (%u. Ok( ($ u) o (($ s2) o s1), $ u (TVar m2), Suc m2) )))"
+ ( (s1,t1,m1) := W e1 a n;
+ (s2,t2,m2) := W e2 ($ s1 a) m1;
+ u := mgu ($ s2 t1) (t2 -> (TVar m2));
+ Ok( ($ u) o (($ s2) o s1), $ u (TVar m2), Suc m2) )"
end