hashcons.mli

(*
 * hashcons: hash tables for hash consing
 * Copyright (C) 2000 Jean-Christophe FILLIATRE
 * 
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License version 2, as published by the Free Software Foundation.
 * 
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * 
 * See the GNU Library General Public License version 2 for more details
 * (enclosed in the file LGPL).
 *)

(*s Hash tables for hash consing. Hash consed values are of the
    following type [hash_consed]. The field [tag] contains a unique
    integer (for values hash consed with the same table). The field
    [hkey] contains the hash key of the value (without modulo) for
    possible use in other hash tables (and internally when hash
    consing tables are resized). The field [node} contains the value
    itself. *)

type 'a hash_consed = { 
  hkey : int;
  tag : int;
  node : 'a }

(*s Functorial interface. *) 

module type HashedType =
  sig
    type t
    val equal : t * t -> bool
    val hash : t -> int
  end

module type S =
  sig
    type key
    type t
    val create : int -> t
(*i
    val clear : t -> unit
i*)
    val hashcons : t -> key -> key hash_consed
(*i
    val iter : (key hash_consed -> unit) -> t -> unit
    val stat : t -> unit
i*)
  end

module Make(H : HashedType) : (S with type key = H.t)