## Outdated egg!

This is an egg for CHICKEN 4, the unsupported old release. You're almost certainly looking for the CHICKEN 5 version of this egg, if it exists.

If it does not exist, there may be equivalent functionality provided by another egg; have a look at the egg index. Otherwise, please consider porting this egg to the current version of CHICKEN.

## binary-heap

Binary heap.

## TOC »

## Usage

(require-extension binary-heap)

## Documentation

The `binary-heap` library is based on the Ocaml heap implementation by Jean-Christophe Filliatre.

Heaps are encoded as binary trees that have the heap property, namely the value of any node is greater or equal than the nodes in its left and right subtrees.

A binary-heap object is created by procedure `make-binary-heap`, the only user-visible procedure defined in this egg:

`make-binary-heap:`procedurewhere KEY-COMPARE-PROC is a user-supplied function that takes two keys and returns a negative, positive, or zero number depending on how the first key compares to the second.

The returned selector procedure can take one of the following arguments:

`'get-max`- returns a (key . value) pair for an association in the heap with the largest key. If the heap is empty, an error is signalled.
`'delete-max`- removes the max key and the corresponding association from the heap. Returns a (key . value) pair of the removed association. If the heap is empty, an error is signalled.
`'empty?`- returns
`#t`if the heap is empty `'size`- returns the size (the number of associations) in the heap
`'put`- pure variant of
`PUT!`; it returns a new heap object that contains the given association, while the original heap object is unmodified. `'for-each`- returns a procedure
`LAMBDA PROC`that will apply the given procedure PROC to each (key . value) association of the heap, from the one with the smallest key all the way to the one with the max key, in an ascending order of keys. `'fold`- returns a procedure
`LAMBDA PROC INITIAL`such that, given the associations in the heap ordered by the descending order of keys:`(key-n . value-n) ... (key-2 . value-2) (key-1 . value-1)`the procedure returns the result of the successive function applications`(PROC value-1 (PROC value-2 ... (PROC value-n INITIAL)`.

## Examples

## About this egg

### Author

### Version history

- 1.2
- Test script updated to return proper exit code
- 1.1
- Documentation converted to wiki format
- 1.0
- Initial release

### License

Copyright 2009-2011 Ivan Raikov. This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. A full copy of the GPL license can be found at <http://www.gnu.org/licenses/>.