package Carpet;
use base qw(Class::InsideOut);  # base class that does the work
use Class::InsideOut::Accessor; # filter that generates accessors
use Class::InsideOut::YAML;     # allow YAML serialisation

sub new {bless [], shift};

{
    # declare object attributes
    my (%width, %height) : Field;   
    
    sub area {
        my $self = shift->self; # get the hash key for $self        
        $width{$self} * $height{$self};
    };
}

{   
    # another object attribute, note the scoping
    my %unit_price : Field; 
    
    sub price {
        my $self = shift;
        $self->area * $unit_price{$self->self};

    };
};

# note, we are forced to use methods since the hashes are scoped
# to the blocks enclosing the methods - now *that's* private :-)
sub display {
    my $self = shift;   
    my ($width, $height, $area, $unit_price, $price) = ($self->width, 
        $self->height, $self->area, $self->unit_price, $self->price);
    print "$width x $height ($area sq m) @ \$$unit_price = \$$price\n";
};

# note lack of DESTROY method - all done automagically