package RomanNumber; use Roman 'roman'; sub new { my $class = shift; my $self = { value => shift }; bless $self, $class; } sub as_num { my $self = shift; return $self->{value}; } sub as_string { my $self = shift; return roman($self->as_num); } sub compare { my ($a,$b) = @_; return ($a->as_num <=> $b->as_num); } use overload '0+' => \&as_num, '""' => \&as_string, '<=>' => \&compare;