use constant powerOn => 0;
use constant lightOn => 1;
{ my $status;
sub setStatus
{
  my $bit = shift;
  vec($status, $bit, 1) = 1;
}
sub resetStatus
{
  my $bit = shift;
  vec($status, $bit, 1) = 0;
}
sub getStatus
{
  my $bit = shift;
  vec($status, $bit, 1);
}

}

##</code><code>##

{ my $status;
my %types = ( powerOn => 0, lightOn => 1 );
sub _bit { if (exists $types{$_[0]}) { $types{$_[0]} } else { die "Unknown bit $_[0]"} }
sub setStatus
{
  my $bit = _bit(shift);
  vec($status, $bit, 1) = 1;
}
# etc.
}
# call as...
setStatus('powerOn');