(*****************************************************************************

  Liquidsoap, a programmable stream generator.
  Copyright 2003-2024 Savonet team

  This program is free software; you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation; either version 2 of the License, or
  (at your option) any later version.

  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details, fully stated in the COPYING
  file at the root of the liquidsoap distribution.

  You should have received a copy of the GNU General Public License
  along with this program; if not, write to the Free Software
  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301  USA

 *****************************************************************************)

type 'a t = 'a list

let create () = []
let add el set = el :: List.filter (fun e -> e != el) set
let mem = List.memq

let of_list l =
  List.fold_left
    (fun ret el -> if List.memq el ret then ret else el :: ret)
    [] l

let compare = Stdlib.compare
let elements l = l
let cardinal = List.length
let choose = function [] -> raise Not_found | x :: _ -> x
let is_empty = function [] -> true | _ -> false
