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Subject: Re: [Caml-list] Is arrow programming impossible in ocaml?
From: skaller <skaller@ozemail.com.au>
Reply-To: skaller@ozemail.com.au
To: Nick Name <nick.name@inwind.it>
Cc: caml-list@inria.fr
In-Reply-To: <200310140159.20515.nick.name@inwind.it>
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On Tue, 2003-10-14 at 09:59, Nick Name wrote:
> Hi all, I am trying to work on a project where I need ocaml efficiency 

> type ('a,'b) t = 'a -> 'b
> 
> let rec arr f = f
> 
> let a = arr (fun x -> x)
> -
> 
> and "a" is typed like '_a -> '_a , where I would like it to be typed 'a 
> -> 'a.
> 
> Does anyone think I have other possibilities in writing that kind of 
> higher-order combinator based code, or is it impossible?

It works fine with an annotation:
# type ('a,'b) t = 'a -> 'b
 
  let rec arr f = f
   
  let a = arr   (fun x -> x)
  ;;
type ('a, 'b) t = 'a -> 'b
val arr : 'a -> 'a = <fun>
val a : '_a -> '_a = <fun>
# let a:('a,'a) t = (fun x -> x)
  ;;
val a : ('a, 'a) t = <fun>
# a 1;;
- : int = 1
# a 1.1;;
- : float = 1.1
#


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