]> Hello, While playing with the current cvs version of ocaml (3.04+15), several questions came to me concerning the semantics of polymorphic methods. For example : # class c = object method ~m: 'a . unit -> 'a -> 'a = fun _ x -> x end;; class c : object method m : unit -> 'a -> 'a end # let f = (new c)#m ();; val f : '_a -> '_a = <fun> Shouldn't the type of f be : 'a -> 'a ? (Would it be sound/implementable/easy to add ?) Second question: # class ['a] d = object method m: 'a -> 'a = fun x -> x end;; class ['a] d : object method m : 'a -> 'a end # class subd = object method ~m: 'a. 'a -> 'a = fun x -> x end;; class subd : object method m : 'a -> 'a end # let v = (new subd :> 'a d);; Characters 9-17: let v = (new subd :> 'a d);; ^^^^^^^^ This expression cannot be coerced to type 'a d = < m : 'a -> 'a >; it has type subd = < m : 'b. 'b -> 'b > but is here used with type 'a d Or even the easier : # class d' = object method m x = x + 0 end;; class d' : object method m : int -> int end # let v' = (new subd :> d');; Characters 10-18: let v' = (new subd :> d');; ^^^^^^^^ This expression cannot be coerced to type d' = < m : int -> int >; it has type subd = < m : 'a. 'a -> 'a > but is here used with type d' But the type ('b. 'b -> 'b) is more general than ('a -> 'a) or (int -> int), no ? Can someone give me some hints why I can't coerce subd ? Btw, thanks for the upcoming release, it seems _really_ excellent ! Nadji ------------------- To unsubscribe, mail caml-list-request@inria.fr Archives: http://caml.inria.fr Bug reports: http://caml.inria.fr/bin/caml-bugs FAQ: http://caml.inria.fr/FAQ/ Beginner's list: http://groups.yahoo.com/group/ocaml_beginners