Module Belt_MutableQueue

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.

val make : unit -> 'a t
  • returns

    a new queue, initially empty.

val clear : 'a t -> unit

Discard all elements from the queue.

val isEmpty : 'a t -> bool
  • returns

    true if the given queue is empty, false otherwise.

val fromArray : 'a array -> 'a t

fromArray a is equivalent to Array.forEach a (add q a)

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

add q x adds the element x at the end of the queue q.

val peek : 'a t -> 'a option

peekOpt q returns the first element in queue q, without removing it from the queue.

val peekUndefined : 'a t -> 'a Js.undefined

peekUndefined q returns undefined if not found

val peekExn : 'a t -> 'a

peekExn q

raise an exception if q is empty

val pop : 'a t -> 'a option

pop q removes and returns the first element in queue q.

val popUndefined : 'a t -> 'a Js.undefined

popUndefined q removes and returns the first element in queue q. it will return undefined if it is already empty

val popExn : 'a t -> 'a

popExn q

raise an exception if q is empty

val copy : 'a t -> 'a t

copy q

  • returns

    a fresh queue

val size : 'a t -> int
  • returns

    the number of elements in a queue.

val mapU : 'a t -> ('a -> 'b) Js.Fn.arity1 -> 'b t
val map : 'a t -> ('a -> 'b) -> 'b t
val forEachU : 'a t -> ('a -> unit) Js.Fn.arity1 -> unit
val forEach : 'a t -> ('a -> unit) -> unit

forEach q f 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 reduceU : 'a t -> 'b -> ('b -> 'a -> 'b) Js.Fn.arity2 -> 'b
val reduce : 'a t -> 'b -> ('b -> 'a -> 'b) -> 'b

reduce q accu f is equivalent to List.reduce l accu f, 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 forEach (fun x -> add x q2) q1; clear q1, but runs in constant time.

val toArray : 'a t -> 'a array

First added will be in the beginning of the array