(* module Ptset =
struct
  include Set.Make (struct type t = int let compare = (-) end)
  let hash = Hashtbl.hash
end
  *)
module M  : FiniteCofinite.S with type elt = Tag.t and type set = Ptset.Int.t =
  FiniteCofinite.Make(Ptset.Int)
include M


let tag t = singleton t
let pcdata = singleton Tag.pcdata
let attribute = singleton Tag.attribute
let star = diff any (add Tag.attribute_data (cup pcdata attribute))
let node = neg attribute

let print ppf t =
  let print_set s =
    Format.fprintf ppf "{";
    Ptset.Int.iter
      (fun t -> Format.fprintf ppf "'%s' " (Tag.to_string t))
      s;
    Format.fprintf ppf "}"
  in
  if is_finite t then
       if is_empty t then
       Format.fprintf ppf "∅" else  print_set (positive t)
  else begin
    Format.fprintf ppf "Σ";
    if not (is_any t) then
      (Format.fprintf ppf "\\" ; print_set (negative t))
  end