]> Hi all, when trying to implement lists with objects and classes, I run into the following issue. The idea is to define a class type list, parameterized over the type 'a of elements, and containing the methods is_nil, hd, tl, map. Then, I planned to define two classes nil and cons for building objects of type list. The problem arises during the typing of list: # class type ['a] list = object method is_nil : bool method hd : 'a method tl : 'a list method map : ('a -> 'b) -> 'b list end ;; class type ['a] list = object method hd : 'a method is_nil : bool method map : ('a -> 'a) -> 'a list method tl : 'a list end The method map has type ('a -> 'a) -> 'a list, which is not what I want. Trying to explicitely quantify 'b is also wrong, because 'b escapes its scope. Does someone know how to make this work? ------------------- 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