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(* Open Source License                                                       *)
(* Copyright (c) 2018 Dynamic Ledger Solutions, Inc. <contact@tezos.com>     *)
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(* copy of this software and associated documentation files (the "Software"),*)
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(* DEALINGS IN THE SOFTWARE.                                                 *)
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(** [remove nb list] remove the first [nb] elements from the list [list]. *)
val remove : int -> 'a list -> 'a list

(** [repeat n x] is a list of [n] [x]'s *)
val repeat : int -> 'a -> 'a list

(** [shift (hd :: tl)] computes [tl @ [hd]] *)
val shift : 'a list -> 'a list

(** [product a b] computes the Cartesian product of two lists [a] and [b]. *)
val product : 'a list -> 'b list -> ('a * 'b) list

(** [take_n n l] returns the [n] first elements of [l]. When [compare]
    is provided, it returns the [n] greatest element of [l]. *)
val take_n : ?compare:('a -> 'a -> int) -> int -> 'a list -> 'a list

(** [split_n n l] is a pair of lists [(j, k)] where [j] contains the [n] first
    elements of [l] and [k] the remainder elements. If [l] has less than or
    exactly [n] elements, [j] is [l] and [k] is [[]]. *)
val split_n : int -> 'a list -> 'a list * 'a list

(** Bounded sequence: keep only the [n] greatest elements. *)
module Bounded (E : Set.OrderedType) : sig
  type t

  val create : int -> t

  val insert : E.t -> t -> unit

  val get : t -> E.t list
end

(** [select n l] is ([n]th element of [l], [l] without that element) *)
val select : int -> 'a list -> 'a * 'a list

(** [filter_map f l] is [[y for x in l where (f x) = Some y]] *)
val filter_map : ('a -> 'b option) -> 'a list -> 'b list

(** [rev_sub l n] is [List.rev l] capped to max [n] elements *)
val rev_sub : 'a list -> int -> 'a list

(** [sub l n] is [l] capped to max [n] elements *)
val sub : 'a list -> int -> 'a list

(** Like [List.hd], but [Some hd] or [None] if empty *)
val hd_opt : 'a list -> 'a option

(** Last elt of list, or raise Not_found if empty *)
val last_exn : 'a list -> 'a

(** [merge_filter2 ~compare ~f l1 l2] merges two lists ordered by [compare]
    and whose items can be merged with [f]. Item is discarded or kept whether
    [f] returns [Some] or [None] *)
val merge_filter2 :
  ?finalize:('a list -> 'a list) ->
  ?compare:('a -> 'a -> int) ->
  ?f:('a option -> 'a option -> 'a option) ->
  'a list ->
  'a list ->
  'a list

(** [merge2 ~compare ~f l1 l2] merges two lists ordered by [compare] and
    whose items can be merged with [f] *)
val merge2 :
  ?finalize:('a list -> 'a list) ->
  ?compare:('a -> 'a -> int) ->
  ?f:('a -> 'a -> 'a) ->
  'a list ->
  'a list ->
  'a list

(** [shuffle l] is a list that contains the same elements as [l] but in a random
    order. *)
val shuffle : 'a list -> 'a list