(* Polymorphic sets *)

module RB = RedBlack

type 'elt t = {
  tree : 'elt RB.t;
  cmp  : 'elt -> 'elt -> int
}

type 'elt set = 'elt t

let create ~cmp = {tree = RB.empty; cmp}

let empty set = {tree = RB.empty; cmp=set.cmp}

let is_empty set = RB.is_empty set.tree

let add elt set = {set with tree = RB.add ~cmp:set.cmp RB.New elt set.tree}

let find elt set =
  try RB.find ~cmp:set.cmp elt set.tree with
    Not_found -> raise Not_found

let find_opt elt set = RB.find_opt ~cmp:set.cmp elt set.tree

let mem elt set = match RB.find_opt ~cmp:set.cmp elt set.tree with None -> false | Some _ -> true

type 'a added = {set : 'a set; duplicates : 'a list; added : 'a list}

let add_list elts set =
  let aux = fun {set ; duplicates ; added} elt ->
    if mem elt set
    then {set; duplicates = elt :: duplicates ; added}
    else {set = add elt set; duplicates; added = elt :: added} in
  List.fold_left aux {set; duplicates=[]; added = []} elts

let elements set = RB.elements set.tree

let get_compare set = set.cmp

let iter f set = RB.iter f set.tree

let fold_inc f set = RB.fold_inc (fun ~elt -> f elt) set.tree