[Caml-list] Memoize GADT

[Christophe Papazian <christophe.papazian@gmail.com>]

Hi,

this must be a very basic question for some of you, sorry for the inconvenience :

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 results of the expensive to compute "f".

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

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

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