(*
Copyright (c) 2013, Simon Cruanes
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(** {1 Random-Access Lists} *)

(** This is an OCaml implementation of Okasaki's paper
    "Purely Functional Random Access Lists". It defines a list-like data
    structure with O(1) cons/tail operations, and O(log(n)) lookup/modification
    operations.
*)

type +'a t
  (** List containing elements of type 'a *)

val empty : 'a t
  (** Empty list *)

val is_empty : _ t -> bool
  (** Check whether the list is empty *)

val cons : 'a -> 'a t -> 'a t
  (** Add an element at the front of the list *)

val hd : 'a t -> 'a
  (** First element of the list, or @raise Invalid_argument if the list is empty *)

val tl : 'a t -> 'a t
  (** Remove the first element from the list,
      or @raise Invalid_argument if the list is empty *)

val length : 'a t -> int
  (** Number of elements *)

val get : 'a t -> int -> 'a
  (** [get l i] accesses the [i]-th element of the list. O(log(n)).
      @raise Invalid_argument if the list has less than [i+1] elements. *)

val set : 'a t -> int -> 'a -> 'a t
  (** [set l i v] sets the [i]-th element of the list to [v]. O(log(n)).
      @raise Invalid_argument if the list has less than [i+1] elements. *)

val iter : 'a t -> ('a -> unit) -> unit
  (** Iterate on the list's elements *)

val fold : 'a t -> 'b -> ('b -> 'a -> 'b) -> 'b
  (** Fold on the list's elements *)

val of_list : 'a list -> 'a t
  (** Convert a list to a RAL. {b Caution}: non tail-rec *)

val to_list : 'a t -> 'a list