The type of queues containing elements of type 'a.

• returns

  a new queue, initially empty.

Discard all elements from the queue.

• returns

  true if the given queue is empty, false otherwise.

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

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

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

peekUndefined q returns undefined if not found

peekExn q

raise an exception if q is empty

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

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

popExn q

raise an exception if q is empty

copy q

• returns

  a fresh queue

• returns

  the number of elements in a queue.

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.

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.

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.

First added will be in the beginning of the array