[Haskell-beginners] Y-combinator

[edgar at ymonad.com]

http://lmgtfy.com/?q=y+combinator+haskell

Cheers,
Edgar

On Wed, 24/Feb/2010 at 20:41 +0000, Jon Harrop wrote:
> 
> OCaml can do this:
> 
> $ ocaml -rectypes
>         Objective Caml version 3.11.1
> 
> # let fix f = (fun x -> f(x x)) (fun x y -> f(x x) y);;
> val fix : (('a -> 'b) -> 'a -> 'b) -> 'a -> 'b = <fun>
> 
> # fix (fun f -> function 0 -> 1 | n -> n*f(n-1)) 10;;
> - : int = 3628800
> 
> Haskell 98 doesn't seem to be able to type check that definition of the 
> y-combinator directly. Is there a Haskell extension that would let it handle 
> this?
> 
> -- 
> Dr Jon Harrop, Flying Frog Consultancy Ltd.
> http://www.ffconsultancy.com/?e
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