module type S =
  sig
    type data
    type t
    val make : data -> t
    val node : t -> data
    val hash : t -> int
    val uid : t -> int
    val equal : t -> t -> bool
  end
module Make :
  functor (H : Hashtbl.HashedType) ->
sig
  type data = H.t
  type t
  val make : data -> t
  val node : t -> data
  val hash : t -> int
  val uid : t -> int
  val equal : t -> t -> bool
end