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From: Christophe Papazian <christophe.papazian@gmail.com>
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Date: Wed, 6 Feb 2013 09:19:16 +0100
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To: Caml List <caml-list@inria.fr>
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Subject: [Caml-list] Memoize GADT

Hi,

this must be a very basic question for some of you, sorry for the inconveni=
ence :

When I have function "f" of type (a -> b), I can easily add a layer to that=
 function to memoize the result by using a (a,b) Hashtbl.t to store the res=
ults of the expensive to compute "f".

let mf =3D let e =3D Hashtbl.create 0 in ( fun x -> try Hashtbl.find e x wi=
th Not_found -> let res =3D f x in Hashtbl.add e x res; res )

But now, I have a function "g"=20
	let g (type a) : a gadt -> a =3D ....

And If I apply the same method, type a becomes weak (_'a).

Is there something simple to memoize that function as easy as the previous =
example and keep its polymorphism ? I think not, but I hope to be wrong.

Thanks

	Christophe