# Perl:
sub set_area_to {
    my $self = shift;
    my ($area) = @_;

    $self->{radius} = sqrt( $area / $PI );

    return;
}

# Ruby
def area= (new_area)
    @radius = Math.sqrt( new_area / @@PI )
end

# Note, this means that the Ruby version allows for:
#   circle.area = 22
# And it will DWIM