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(librep.info)Queues

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Queues
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   A "queue" is an ordered set of objects, such that objects enter at
one end of the queue (the "tail"), and leave from the other end of the
queue (the "head"). The acts of entering and leaving a queue are often
called "enqueing" and "dequeueing".

   `librep' provides a straightforward queue implementation,
implemented by the `rep.data.queues' module (Note: Modules).

 - Function: make-queue
     Create and return a new queue object. The queue will initially be
     empty.

 - Function: enqueue q arg
     Add the object ARG to the tail of the queue Q.

 - Function: dequeue q
     Remove the object at the head of the queue Q, and return it. If Q
     is empty, an error is signalled.

 - Function: queue-empty-p q
     Return true if the queue Q is not empty.

 - Function: queuep arg
     Return true if the object ARG is a queue.

 - Function: queue->list q
     Return a list of objects representing the contents of the queue Q,
     with objects ordered from head to tail. Modifying the list
     structure causes undefined effects to the queue itself.

 - Function: queue-length q
     Return the number of objects stored in the queue Q.

 - Function: delete-from-queue q arg
     Removes any occurrences of the object ARG from the queue Q.