(*
Copyright (c) 2013, Simon Cruanes
All rights reserved.

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modification, are permitted provided that the following conditions are met:

Redistributions of source code must retain the above copyright notice, this
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form must reproduce the above copyright notice, this list of conditions and the
following disclaimer in the documentation and/or other materials provided with
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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*)

(** {1 Mutable polymorphic hash-set} *)

type 'a t = ('a, unit) PHashtbl.t
  (** A set is a hashtable, with trivial values *)

val empty : ?max_load:float -> ?eq:('a -> 'a -> bool) ->
            ?hash:('a -> int) -> int -> 'a t
  (** See {!PHashtbl.create} *)

val copy : 'a t -> 'a t

val clear : 'a t -> unit

val cardinal : 'a t -> int

val mem : 'a t -> 'a -> bool

val add : 'a t -> 'a -> unit

val remove : 'a t -> 'a -> unit

val iter : ('a -> unit) -> 'a t -> unit

val fold : ('b -> 'a -> 'b) -> 'b -> 'a t -> 'b

val filter : ('a -> bool) -> 'a t -> unit
  (** destructive filter (remove elements that do not satisfy the predicate) *)

val to_seq : 'a t -> 'a Sequence.t

val of_seq : 'a t -> 'a Sequence.t -> unit

val union : ?into:'a t -> 'a t -> 'a t -> 'a t
  (** Set union. The result is stored in [into] *)

val inter : ?into:'a t -> 'a t -> 'a t -> 'a t
  (** Set intersection. The result is stored in [into] *)