ocaml/stdlib/queue.mli

54 lines
1.9 KiB
OCaml

(***********************************************************************)
(* *)
(* Objective Caml *)
(* *)
(* Xavier Leroy, projet Cristal, INRIA Rocquencourt *)
(* *)
(* Copyright 1996 Institut National de Recherche en Informatique et *)
(* en Automatique. All rights reserved. This file is distributed *)
(* under the terms of the GNU Library General Public License, with *)
(* the special exception on linking described in file ../LICENSE. *)
(* *)
(***********************************************************************)
(* $Id$ *)
(** First-in first-out queues.
This module implements queues (FIFOs), with in-place modification.
*)
type 'a t
(** The type of queues containing elements of type ['a]. *)
exception Empty
(** Raised when {!Queue.take} or {!Queue.peek} is applied to an empty queue. *)
val create : unit -> 'a t
(** Return a new queue, initially empty. *)
val add : 'a -> 'a t -> unit
(** [add x q] adds the element [x] at the end of the queue [q]. *)
val take : 'a t -> 'a
(** [take q] removes and returns the first element in queue [q],
or raises [Empty] if the queue is empty. *)
val peek : 'a t -> 'a
(** [peek q] returns the first element in queue [q], without removing
it from the queue, or raises [Empty] if the queue is empty. *)
val clear : 'a t -> unit
(** Discard all elements from a queue. *)
val length : 'a t -> int
(** Return the number of elements in a queue. *)
val iter : ('a -> unit) -> 'a t -> unit
(** [iter f q] applies [f] in turn to all elements of [q],
from the least recently entered to the most recently entered.
The queue itself is unchanged. *)