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 take 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: f:('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.