package Heap
::Elem
::RefRev
;
use vars
qw($VERSION @ISA @EXPORT @EXPORT_OK);
@ISA = qw(Exporter AutoLoader Heap::Elem);
# Available for export: RefRElem (to allocate a new Heap::Elem::RefRev value)
@EXPORT_OK = qw( RefRElem );
# Preloaded methods go here.
$class = ref($class) || $class;
# two slot array, 0 for the reference value, 1 for use by Heap
my $self = [ shift, undef ];
return bless $self, $class;
sub RefRElem
{ # exportable synonym for new
Heap
::Elem
::RefRev
->new(@_);
@_ ?
($self->[0] = shift) : $self->[0];
@_ ?
($self->[1] = shift) : $self->[1];
# compare two RefRev elems - the objects must have a compatible cmp method
return $other->[0]->cmp( $self->[0] );
# Autoload methods go after =cut, and are processed by the autosplit program.
Heap::Elem::RefRev - Perl extension for reversed Object Reverence Heap Elements
use Heap::Elem::RefRev( RefRElem );
my $heap = Heap::Fibonacci->new;
$obj = myObject->new( $i );
$elem = RefRElem( $obj );
while( defined( $elem = $heap->extract_top ) ) {
# assume that myObject object have a method I<printable>
print "Largest is ", $elem->val->printable, "\n";
Heap::Elem::RefRev is used to wrap object reference values into an
element that can be managed on a heap. Each referenced object must
have a method I<cmp> which can compare itself with any of the other
objects that have references on the same heap. These comparisons
must be consistant with normal arithmetic. The top of the heap will
have the largest (according to I<cmp>) element still remaining.
(See L<Heap::Elem::Ref> if you want the heap to always return the
The details of the Elem interface are described in L<Heap::Elem>.
The details of using a Heap interface are described in L<Heap>.
John Macdonald, jmm@perlwolf.com
Copyright 1998-2003, O'Reilly & Associates.
This code is distributed under the same copyright terms as perl itself.
Heap(3), Heap::Elem(3), Heap::Elem::Ref(3).