sub is_alive { my $self = shift; return 0 + exists $self->{Cells}->{ join ':', @_ }; } # Return the list of dead cells surrounding a cell sub get_dead_cells { my ( $self, $x, $y ) = @_; ( (join ':', $x - 1, $y - 1) x !$self->is_alive($x - 1, $y - 1), (join ':', $x - 1, $y ) x !$self->is_alive($x - 1, $y ), (join ':', $x - 1, $y + 1) x !$self->is_alive($x - 1, $y + 1), (join ':', $x , $y - 1) x !$self->is_alive($x , $y - 1), (join ':', $x , $y + 1) x !$self->is_alive($x , $y + 1), (join ':', $x + 1, $y - 1) x !$self->is_alive($x + 1, $y - 1), (join ':', $x + 1, $y ) x !$self->is_alive($x + 1, $y ), (join ':', $x + 1, $y + 1) x !$self->is_alive($x + 1, $y + 1) ); } sub get_num_live { my ( $self, $x, $y ) = @_; $self->is_alive( $x - 1, $y - 1 ) + $self->is_alive( $x - 1, $y ) + $self->is_alive( $x - 1, $y + 1 ) + $self->is_alive( $x , $y - 1 ) + $self->is_alive( $x , $y + 1 ) + $self->is_alive( $x + 1, $y - 1 ) + $self->is_alive( $x + 1, $y ) + $self->is_alive( $x + 1, $y + 1 ); }