(************************************************************************)
(*         *   The Coq Proof Assistant / The Coq Development Team       *)
(*  v      *   INRIA, CNRS and contributors - Copyright 1999-2018       *)
(* <O___,, *       (see CREDITS file for the list of authors)           *)
(*   \VV/  **************************************************************)
(*    //   *    This file is distributed under the terms of the         *)
(*         *     GNU Lesser General Public License Version 2.1          *)
(*         *     (see LICENSE file for the text of the license)         *)
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(** Generic functorized trie data structure. *)

module type S =
sig
  (** A trie is a generalization of the map data structure where the keys are
      themselves lists. *)

  type label
  (** Keys of the trie structure are [label list]. *)

  type data
  (** Data on nodes of tries are finite sets of [data]. *)

  type t
  (** The trie data structure. Essentially a finite map with keys [label list]
      and content [data Set.t]. *)

  val empty : t
  (** The empty trie. *)

  val get : t -> data
  (** Get the data at the current node. *)

  val next : t -> label -> t
  (** [next t lbl] returns the subtrie of [t] pointed by [lbl].
      @raise Not_found if there is none. *)

  val labels : t -> label list
  (** Get the list of defined labels at the current node. *)

  val add : label list -> data -> t -> t
  (** [add t path v] adds [v] at path [path] in [t]. *)

  val remove : label list -> data -> t -> t
  (** [remove t path v] removes [v] from path [path] in [t]. *)

  val iter : (label list -> data -> unit) -> t -> unit
  (** Apply a function to all contents. *)

end

module type Grp =
sig
  type t
  val nil : t
  val is_nil : t -> bool
  val add : t -> t -> t
  val sub : t -> t -> t
end

module Make (Label : Set.OrderedType) (Data : Grp) : S
  with type label = Label.t and type data = Data.t
(** Generating functor, for a given type of labels and data. *)