module type EltSig = 
sig
   type elt (* type of elements *)

   (* Comparison function *)
   val compare : elt -> elt -> int
end

module type SetSig = 
sig
   type elt     (* type of elements in the set *)
   type t       (* type of sets *)

   (* Create a new set *)
   val create : unit -> t

   (* Test for membership *)
   val mem : elt -> t -> bool

   (* Add an element to the set *)
   val insert : elt -> t -> t

   (* Delete an element from the set *)
   val delete : elt -> t -> t
end

module MakeSplaySet (Elt : EltSig)
   : SetSig with type elt = Elt.elt