NAME Array::Heap - treat perl arrays as heaps (priority queues) SYNOPSIS use Array::Heap; DESCRIPTION There are a multitude of heap and heap-like modules on CPAN, you might want to search for /Heap/ and /Priority/ to find many. They implement more or less fancy datastructures that might well be what you are looking for. This module takes a different approach: It exports functions (i.e. not object orientation) that are loosely modeled after the C++ STL's heap functions. They all take an array as argument, just like perl's built-in functions "push", "pop" etc. The implementation itself is in C for maximum speed (although I doubt it makes that much of a difference). FUNCTIONS All of the following functions are being exported by default. make_heap @heap (\@) Reorders the elements in the array so they form a heap, with the lowest value "on top" of the heap (corresponding to the first array element). make_heap_cmp { compare } @heap (&\@) Just like "make_heap", but takes a custom comparison function. push_heap @heap, $element, ... (\@@) Adds the given element(s) to the heap. push_heap_cmp { compare } @heap, $element, ... (&\@@) Just like "push_heap", but takes a custom comparison function. pop_heap @heap (\@) Removes the topmost (lowest) heap element and repairs the heap. pop_heap_cmp { compare } @heap (&\@) Just like "pop_heap", but takes a custom comparison function. COMPARISON FUNCTIONS All the functions come in two flavours: one that uses the built-in comparison function and one that uses a custom comparison function. The built-in comparison function can either compare scalar numerical values, or array refs. If the elements to compare are array refs, the first element of the array is used for comparison, i.e. 1, 4, 6 will be sorted according to their numerical value, [1 => $obj1], [2 => $obj2], [3 => $obj3] will sort according to the first element of the arrays, i.e. "1,2,3". The custom comparison functions work similar to how "sort" works: $a and $b are set to the elements to be compared, and the result should be either -1 if $a is less than $b, or ">= 0" otherwise. The first example above corresponds to this comparison "function": { $a <=> $b } And the second example corresponds to this: { $a->[0] <=> $b->[0] } Unlike "sort", the default sort is numerical and it is not possible to use normal subroutines. BUGS This module works not work with tied or magical arrays or array elements. AUTHOR Marc Lehmann http://www.goof.com/pcg/marc/