Summary

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       File:     pqueue.icn

       Subject:  Class MaxPQueue, implementing a max-priority queue.
                 Also see Steve Wampler's more general priority queue.

       Authors:  Kostas Oikonomou
                 Based on pqueue.icn in the IPL, by William S. Evans and
                 Gregg M. Townsend.

       Date:     September 15, 2004

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   This file is in the public domain.

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       Methods:

	construct(S)	returns a max-priority queue containing the elements
			in  the structure (list, table, or set) S of "elem"
                       records, each containing a "data" and a numeric
                       "priority" field.

	get()	        removes and returns the highest priority element
			from the priority queue.

	put(e)	        adds element e (a "elem" record) to the queue.

	gen()	        generates (non-destructively) the elements of the queue
                       in order, highest priority first.

       len()           returns the number of elements in the queue.
       maxlen()        returns the maximum length reached by the queue during
                       its lifetime.

	elem(d, p)	constructs a record with data d and priority p.


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	The priority queue is implemented as a max-heap.  The heap is
	implemented by a list in the usual fashion.

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This file is part of the (main) package.