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Defining type that requires hashtables with recursive definition
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Date: -- (:)
From: Hugo Ferreira <hmf@i...>
Subject: Re: [Caml-list] Defining type that requires hashtables with recursive definition

Thomas Gazagnaire wrote:
> or if you really want to define your own equality, you can use recursive 
> modules:
> 
> module rec H : Hashtbl.HashedType =
> struct
>     type node =
>         | Node of node J.t
>         | Leaf of int
> 
>     type t = node
>     let equal (e1:node) (e2:node) = (==) e1 e2
>     let hash (e:node) = Hashtbl.hash e
> end
> 
> and J : Hashtbl.S = Hashtbl.Make( H )
>

Yes, looks like what I need.

Thanks,
Hugo F.



> 2009/1/19 Jacques Carette <carette@mcmaster.ca <mailto:carette@mcmaster.ca>>
> 
>     Hugo Ferreira wrote:
> 
>         I am attempting to define a type so:
> 
>         type node =
>          | Node of links
>          | Leaf of int
> 
>         And I want to implement links as a
>         hashtable whose keys and values are
>         also of type node.
> 
> 
>     type node =
>      | Node of links
>      | Leaf of int
>     and links = (node, node) Hashtbl.t
> 
>     should do it.
> 
>     Jacques
> 
> 
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