diff -r dd0f298b024c -r 477c05586286 src/HOL/MiniML/W.thy --- a/src/HOL/MiniML/W.thy Fri Jan 17 18:35:44 1997 +0100 +++ b/src/HOL/MiniML/W.thy Fri Jan 17 18:50:04 1997 +0100 @@ -1,28 +1,38 @@ (* Title: HOL/MiniML/W.thy ID: \$Id\$ - Author: Dieter Nazareth and Tobias Nipkow - Copyright 1995 TU Muenchen + Author: Wolfgang Naraschewski and Tobias Nipkow + Copyright 1996 TU Muenchen Type inference algorithm W *) + W = MiniML + types - result_W = "(subst * typ * nat)maybe" + result_W = "(subst * typ * nat)option" (* type inference algorithm W *) + consts - W :: [expr, typ list, nat] => result_W + W :: [expr, ctxt, nat] => result_W primrec W expr - "W (Var i) a n = (if i < length a then Ok(id_subst, nth i a, n) - else Fail)" - "W (Abs e) a n = ( (s,t,m) := W e ((TVar n)#a) (Suc n); - Ok(s, (s n) -> t, m) )" - "W (App e1 e2) a n = - ( (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) )" + "W (Var i) A n = + (if i < length A then Some( id_subst, + bound_typ_inst (%b. TVar(b+n)) (nth i A), + n + (min_new_bound_tv (nth i A)) ) + else None)" + + "W (Abs e) A n = ( (S,t,m) := W e ((FVar n)#A) (Suc n); + Some( S, (S n) -> t, m) )" + + "W (App e1 e2) A n = ( (S1,t1,m1) := W e1 A n; + (S2,t2,m2) := W e2 (\$S1 A) m1; + U := mgu (\$S2 t1) (t2 -> (TVar m2)); + Some( \$U o \$S2 o S1, U m2, Suc m2) )" + + "W (LET e1 e2) A n = ( (S1,t1,m1) := W e1 A n; + (S2,t2,m2) := W e2 ((gen (\$S1 A) t1)#(\$S1 A)) m1; + Some( \$S2 o S1, t2, m2) )" end