]> > Hi all, I was curious as to how ocaml implements functors and > finding no help with google, I thought I could ask on the > list. Basically, a structure is compiled like a record, and a functor like a function. > After giving it a little thought I was thinking they might be > implemented as follows: > [...] > How far off is Ocaml's way and is the performance comparable? It's pretty close, and the performance is comparable. Here is pseudocode that is closest to the actual compiled code: type 'a orderedtype = { compare: 'a -> 'a -> comparison } type 'a setmodule = { empty: 'a tree; insert: 'a tree -> 'a -> 'a tree; member: 'a tree -> 'a -> bool; } let make compare = let node l v r = Node(l, v, r) in let single v = Node(Empty, v, Empty) in let rec insert t a = match t with Empty -> single a | Node(l, v, r) -> match (compare.compare a v) with LT -> node (insert l a) v r | EQ -> t | GT -> node l v (insert r a) in (* other struct members similar *) { empty = Empty; insert = insert; member = member } let mymodule = make { compare = fun x y -> ... } Now, let me warn you about the following code: > let compare x y = let cmp = x - y in if cmp > 0 then GT else if cmp < 0 then LT else EQ which doesn't work if x and y are sufficiently far apart (e.g. x = max_int and y = min_int). - Xavier Leroy ------------------- 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