This package contains implementations of double-ended queues (aka, deques). See: http://en.wikipedia.org/wiki/Deque deque is a standard double-ended queue. You can push and pop from both ends. Other features include indexing elements from their relative position inside the deque, iterating through the elements, and converting the deque to a list. ideque is a specialized deque that keeps track of the indices of the front and back of the queue so that we may reference items by an absolute, rather than relative, index. The idea is that you can add elements to an ideque (push-back), pop elements off the front (pop-front), and still reference the nth item added directly by n. It probably doesn't make much sense to use push-front with an ideque, but you can. Please see the docstrings for the exported symbols for more information. -------------------------------- Acknowledgments This implementation was originally based off of the deque implementation in the arnesi package: http://common-lisp.net/project/bese/repos/arnesi_dev/src/queue.lisp