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|
(**************************************************************************)
(* *)
(* OCaml *)
(* *)
(* 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 Lesser General Public License version 2.1, with the *)
(* special exception on linking described in the file LICENSE. *)
(* *)
(**************************************************************************)
(** Last-in first-out stacks.
This module implements stacks (LIFOs), with in-place modification.
*)
(** {b Unsynchronized accesses} *)
[@@@alert unsynchronized_accesses
"Unsynchronized accesses to stacks are a programming error."
]
(**
Unsynchronized accesses to a stack may lead to an invalid queue state.
Thus, concurrent accesses to stacks must be synchronized (for instance
with a {!Mutex.t}).
*)
type !'a t
(** The type of stacks containing elements of type ['a]. *)
exception Empty
(** Raised when {!Stack.pop} or {!Stack.top} is applied to an empty stack. *)
val create : unit -> 'a t
(** Return a new stack, initially empty. *)
val push : 'a -> 'a t -> unit
(** [push x s] adds the element [x] at the top of stack [s]. *)
val pop : 'a t -> 'a
(** [pop s] removes and returns the topmost element in stack [s],
or raises {!Empty} if the stack is empty. *)
val pop_opt : 'a t -> 'a option
(** [pop_opt s] removes and returns the topmost element in stack [s],
or returns [None] if the stack is empty.
@since 4.08 *)
val drop : 'a t -> unit
(** [drop s] removes the topmost element in stack [s],
or raises {!Empty} if the stack is empty.
@since 5.1 *)
val top : 'a t -> 'a
(** [top s] returns the topmost element in stack [s],
or raises {!Empty} if the stack is empty. *)
val top_opt : 'a t -> 'a option
(** [top_opt s] returns the topmost element in stack [s],
or [None] if the stack is empty.
@since 4.08 *)
val clear : 'a t -> unit
(** Discard all elements from a stack. *)
val copy : 'a t -> 'a t
(** Return a copy of the given stack. *)
val is_empty : 'a t -> bool
(** Return [true] if the given stack is empty, [false] otherwise. *)
val length : 'a t -> int
(** Return the number of elements in a stack. Time complexity O(1) *)
val iter : ('a -> unit) -> 'a t -> unit
(** [iter f s] applies [f] in turn to all elements of [s],
from the element at the top of the stack to the element at the
bottom of the stack. The stack itself is unchanged. *)
val fold : ('acc -> 'a -> 'acc) -> 'acc -> 'a t -> 'acc
(** [fold f accu s] is [(f (... (f (f accu x1) x2) ...) xn)]
where [x1] is the top of the stack, [x2] the second element,
and [xn] the bottom element. The stack is unchanged.
@since 4.03 *)
(** {1 Stacks and Sequences} *)
val to_seq : 'a t -> 'a Seq.t
(** Iterate on the stack, top to bottom.
It is safe to modify the stack during iteration.
@since 4.07 *)
val add_seq : 'a t -> 'a Seq.t -> unit
(** Add the elements from the sequence on the top of the stack.
@since 4.07 *)
val of_seq : 'a Seq.t -> 'a t
(** Create a stack from the sequence.
@since 4.07 *)
|
