]> On Nov 17, 2003, at 11:37, chris.danx wrote: > let prodAdd x = > let value = ref x in > fun y -> !value + y;; This is very similar to let prodAdd x y = x + y;; The only difference is that I'm making a reference with the value of x. # let prodAdd x = let value = ref x in fun y -> !value + y;; val prodAdd : int -> int -> int = <fun> # let prodAdd2 x y = x + y;; val prodAdd2 : int -> int -> int = <fun> # prodAdd 1 2;; - : int = 3 # prodAdd2 1 2;; - : int = 3 # prodAdd 1;; - : int -> int = <fun> # prodAdd2 1;; - : int -> int = <fun> > Now I want to do a function that takes a ref to a list and returns a > function that adds items to the list and produce a function that > returns another that returns the list. How do I do that? > > let prod_list_acc a = > fun x -> a := x :: !a; true;; > > let return_acc a = > fun () -> !a;; > > but that gives a "unit -> int list" =. How do you get a copy of the > list values? > > > This might seem like a crazy thing to do but I am toying with an idea > relating to a paper I read on traits. Instead of having classes at > all you can just have traits, closures and mutable values. That's not a very functional style. It does seem to work for me with the following syntax, though: # let list_acc a x = a := x :: !a; ();; val list_acc : 'a list ref -> 'a -> unit = <fun> # let return_list a = !a;; val return_list : 'a ref -> 'a = <fun> # return_list a;; - : int list = [1; 2; 3; 4; 5] # list_acc a 6;; - : unit = () # return_list a;; - : int list = [6; 1; 2; 3; 4; 5] -- Dustin Sallings ------------------- 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