Stdlib.Queue(3)

NAME
Stdlib.Queue - no description

Module
Module Stdlib.Queue

Documentation

Module Queue
 : (module Stdlib__Queue)

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 push : 'a -> 'a t -> unit

push is a synonym for add .

val take : 'a t -> 'a

take q removes and returns the first element in queue q , or raises Queue.Empty if the queue is empty.

val take_opt : 'a t -> 'a option

take_opt q removes and returns the first element in queue q , or returns None if the queue is empty.

Since 4.08

val pop : 'a t -> 'a

pop is a synonym for take .

val peek : 'a t -> 'a

peek q returns the first element in queue q , without removing it from the queue, or raises Queue.Empty if the queue is empty.

val peek_opt : 'a t -> 'a option

peek_opt q returns the first element in queue q , without removing it from the queue, or returns None if the queue is empty.

Since 4.08

val top : 'a t -> 'a

top is a synonym for peek .

val clear : 'a t -> unit

Discard all elements from a queue.

val copy : 'a t -> 'a t

Return a copy of the given queue.

val is_empty : 'a t -> bool

Return true if the given queue is empty, false otherwise.

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.

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

fold f accu q is equivalent to List.fold_left f accu l , where l is the list of q 's elements. The queue remains unchanged.

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

transfer q1 q2 adds all of q1 's elements at the end of the queue q2 , then clears q1 . It is equivalent to the sequence iter (fun x -> add x q2) q1; clear q1 , but runs in constant time.

  Iterators

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

Iterate on the queue, in front-to-back order. The behavior is not defined if the queue is modified during the iteration.

Since 4.07

val add_seq : 'a t -> 'a Seq.t -> unit

Add the elements from a sequence to the end of the queue.

Since 4.07

val of_seq : 'a Seq.t -> 'a t

Create a queue from a sequence.

Since 4.07