[Camllist] Functor implementation
 Chris Clearwater
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Date:   (:) 
From:  Chris Clearwater <chris@s...> 
Subject:  [Camllist] Functor implementation 
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. After giving it a little thought I was thinking they might be implemented as follows: type 'a tree = Empty  Node of ('a tree) * 'a * ('a tree) type comparison = GT  EQ  LT let node l v r = Node(l, v, r) let single v = Node(Empty, v, Empty) let rec insert c t a = match t with Empty > single a  Node(l, v, r) > match (c a v) with LT > node (insert c l a) v r  EQ > t  GT > node l v (insert c r a) let rec member c t a = match t with Empty > false  Node(l, v, r) > match (c a v) with LT > member c l a  EQ > true  GT > member c r a (* Functor implementation follows *) type 'a setmodule = { empty: 'a tree; insert: 'a tree > 'a > 'a tree; member: 'a tree > 'a > bool; } let make c = { empty = Empty; insert = insert c; member = member c; } (* Use a functor *) let compare x y = let cmp = x  y in if cmp > 0 then GT else if cmp < 0 then LT else EQ let mymodule = make compare let s = mymodule.insert mymodule.empty 5 EOF How far off is Ocaml's way and is the performance comparable? And on a sidenote, wouldn't it be beneficial for there to be a built in comparison type and a function to convert from integers greater than less than or equal to, to the comparrison type? I imagine this would clarify code that uses comparisons greatly. Thanks in advance for your answers!  To unsubscribe, mail camllistrequest@inria.fr Archives: http://caml.inria.fr Bug reports: http://caml.inria.fr/bin/camlbugs FAQ: http://caml.inria.fr/FAQ/ Beginner's list: http://groups.yahoo.com/group/ocaml_beginners