# more Perlish implementation example (update: simplified)
package UnorderedPair;

use strict;

sub new {
    my $class = shift;
    my $self = bless {};
    @_ and $self -> encode( @_ );
    return $self, $class;
}

sub encode { # x, y, value
    my $self = shift;
    my ( $x, $y ) = NDsc( $_[0], $_[1] );
    $self -> { $x }{ $y } = $_[2];
}

sub decode { # x, y ... return value
    my $self = shift;
    my ( $x, $y ) = NDsc( $_[0], $_[1] );
    return $self -> { $x }{ $y };
}

sub NDsc{ # sort numeric descending
    return sort { $b <=> $a } @_;
}

1;