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Deque

Functions for persistent, double-ended queues.

Type Deque​

type Deque<T> = (List<T>, List<T>)

Double-ended queue

Function empty​

func empty<T>() : Deque<T>

Empty queue

Function isEmpty​

func isEmpty<T>(q : Deque<T>) : Bool

True when the queue is empty

Function pushFront​

func pushFront<T>(q : Deque<T>, x : T) : Deque<T>

Insert a new element on the front end of the queue

Function peekFront​

func peekFront<T>(q : Deque<T>) : ?T

Inspect the (optional) first element on the front end of the queue

Function popFront​

func popFront<T>(q : Deque<T>) : ?(T, Deque<T>)

Remove the first element on the front end of the queue; Returns null when empty.

Function pushBack​

func pushBack<T>(q : Deque<T>, x : T) : Deque<T>

Insert a new element on the back end of the queue

Function peekBack​

func peekBack<T>(q : Deque<T>) : ?T

Inspect the (optional) first element on the back end of the queue

Function popBack​

func popBack<T>(q : Deque<T>) : ?(Deque<T>, T)

Remove the first element on the back end of the queue; Returns null when empty.