Queue¶

A Queue is a collection of any type in kOS. Queues work according to First-In first-out principle. It may be useful to contrast Queue with Stack to better understand how both structures work. You can read more about queues on Wikipedia.

Using a queue¶

SET Q TO QUEUE().
Q:PUSH("alice").
Q:PUSH("bob").

PRINT Q:POP. // will print 'alice'
PRINT Q:POP. // will print 'bob'

Structure¶

structure Queue¶

Members¶
Suffix	Type	Description
`PUSH(item)`	None	add item to the end of the queue
`POP()`	any type	returns the first element in the queue and removes it
`PEEK()`	any type	returns the first element in the queue without removing it
`LENGTH`	integer	number of elements in the queue
`CLEAR()`	None	remove all elements
`ITERATOR`	`Iterator`	for iterating over the queue
`COPY`	`Queue`	a new copy of this queue
`CONTAINS(item)`	boolean	check if queue contains an item
`EMPTY`	boolean	check if queue if empty
`DUMP`	string	verbose dump of all contained elements

Queue:PUSH(item)¶

Parameters:	item – (any type) item to be added

Adds the item to the end of the queue.

Queue:POP()¶: Returns the item in the front of the queue and removes it.

Queue:PEEK()¶: Returns the item in the front of the queue without removing it.

Queue:CLEAR()¶: Removes all elements from the queue.

Queue:LENGTH¶

Type:	integer
Access:	Get only

Returns the number of elements in the queue.

Queue:ITERATOR¶

Type:	`Iterator`
Access:	Get only

An alternate means of iterating over a queue. See: Iterator.

Queue:COPY¶

Type:	`Queue`
Access:	Get only

Returns a new queue that contains the same thing as the old one.

Queue:CONTAINS(item)¶

Parameters:	index – (integer) starting index (from zero)
Returns:	boolean

Returns true if the queue contains an item equal to the one passed as an argument

Queue:EMPTY¶

Type:	boolean
Access:	Get only

Returns true if the queue has zero items in it.

Queue:DUMP¶

Type:	string
Access:	Get only

Returns a string containing a verbose dump of the queue’s contents.