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![]() | Pack logtalk -- logtalk-3.81.0/manuals/_sources/libraries/queues.rst.txt |
.. _library_queues:
queues
This library implements queues. The queue representation should be regarded as an opaque term and only accessed using the library predicates.
Open the `../../docs/library_index.html#queues <../../docs/library_index.html#queues>`__ link in a web browser.
To load all entities in this library, load the loader.lgt
file:
::
| ?- logtalk_load(queues(loader))
.
To test this library predicates, load the tester.lgt
file:
::
| ?- logtalk_load(queues(tester))
.
To create a new queue, use the new/1 predicate:
::
| ?- queue::new(Queue)
.
Queue = ...
yes
Elements can be added to either the end of the queue or the front of the queue using, respectively, the join/3 and join_all/3 predicates or the jump/3 and jump_all/3. For example:
::
| ?- queue::(new(Queue0)
, join_all([1,2,3], Queue0, Queue1)
).
Queue0 = ...,
Queue1 = ...
yes
We can query the head of the queue or remove the head of the queue using, respectively, the head/2 and serve/3 predicates. For example:
::
| ?- queue::(new(Queue0)
, join(1, Queue0, Queue1)
, head(Queue1, Head)
).
Queue0 = ...,
Queue1 = ...,
Head = 1
yes
For details on these and other provided predicates, consult the library API documentation.