use Devel::Peek;
use Readonly;

Readonly my $C1 => 0x0004;
Readonly my $C2 => 0x0008;
                         
Dump($C1);           # before first evaluation
#Dump($C2);

my @x = ($C1, $C2);  # somehow access variables

my $C3 = $C1 | $C2;

Dump($C1);           # after first evaluation
#Dump($C2);

print "\nValue of C3 = ", $C3, "\n";