INCLUDE "utils.ml"
module type S = sig
  type elt
  type 'a node = Nil | Cons of elt * 'a

  module rec Node :
  sig
    include Hcons.S with type data = Data.t
  end
  and Data : sig
    include Hashtbl.HashedType with type t = Node.t node
  end
  type data = Data.t
  type t = Node.t
  val hash : t -> int
  val uid : t -> Uid.t
  val make : data -> t
  val equal : t -> t -> bool
  val nil : t
  val node : t -> t node
  val cons : ?sorted:bool -> elt -> t -> t
  val hd : t -> elt
  val tl : t -> t
  val fold : (elt -> 'a -> 'a) -> t -> 'a -> 'a
  val map : (elt -> elt) -> t -> t
  val iter : (elt -> 'a) -> t -> unit
  val rev : t -> t
  val rev_map : (elt -> elt) -> t -> t
  val length : t -> int
  val mem : elt -> t -> bool
  val stats : unit -> unit
  val init : unit -> unit
end

module Make (H : Hcons.SA) : S with type elt = H.t =
struct
  type elt = H.t
  type 'a node = Nil | Cons of elt * 'a
  module rec Node : Hcons.S with type data = Data.t = Hcons.Make (Data)
  and Data : Hashtbl.HashedType  with type t = Node.t node =
  struct
    type t = Node.t node
    let equal x y =
      match x,y with
	| _,_ when x==y -> true
	| Cons (a,aa), Cons(b,bb) -> (aa==bb) && (H.equal a b)
	| _ -> false
    let hash = function
      | Nil -> 0
      | Cons(a,aa) -> HASHINT3(PRIME3,Uid.to_int (H.uid a),Uid.to_int( aa.Node.id))
  end
  type data = Data.t
  type t = Node.t
  let make = Node.make
  let node x = x.Node.node
  let hash x = x.Node.key
  let equal = Node.equal
  let uid x= x.Node.id
  let nil = Node.make Nil
  let stats = Node.stats
  let init = Node.init
  (* doing sorted insertion allows to make better use of hash consing *)
  let rec sorted_cons e l =
    match l.Node.node with
      |	Nil -> Node.make (Cons(e, l))
      | Cons (x, ll) ->
	  if H.uid e < H.uid x
	  then Node.make (Cons(e, l))
	  else Node.make (Cons(x, sorted_cons e ll))

  let cons e l =
    Node.make(Cons(e, l))

  let cons ?(sorted=true) e l =
    if sorted then sorted_cons e l else cons e l

  let hd = function { Node.node = Cons(a,_) } -> a | _ -> failwith "hd"
  let tl = function { Node.node = Cons(_,a) } -> a | _ -> failwith "tl"

  let fold f l acc =
    let rec loop acc l = match l.Node.node with
      | Nil -> acc
      | Cons (a, aa) -> loop (f a acc) aa
    in
      loop acc l

  let map f l  =
    let rec loop l = match l.Node.node with
      | Nil -> nil
      | Cons(a, aa) -> cons (f a) (loop aa)
    in
      loop l

  let iter f l =
    let rec loop l = match l.Node.node with
      | Nil -> ()
      | Cons(a,aa) ->  (f a);(loop aa)
    in
      loop l

  let rev l = fold cons l nil
  let rev_map f l = fold (fun x acc -> cons (f x) acc) l nil
  let length l = fold (fun _ c -> c+1) l 0
  let rec mem e l =
    match l.Node.node with
      | Nil -> false
      | Cons (x, ll) -> x == e || mem e ll

end