use constant ARRAY => [ 1,2,3,4 ];
print ARRAY->[1];
ARRAY->[1] = " be changed";
print ARRAY->[1];
##</code><code>##

use strict;
use warnings;
use Data::Dumper;

use constant INVALID_DATA => ( q{invalid}, 0 );
use constant ADD_DATA => ( q{add}, 1 );
use constant REMOVE_DATA => ( q{remove}, 2 );
use constant MODES => ( \&ADD_DATA, \&REMOVE_DATA );

print {*STDERR} "Dumping MODES: " . Dumper ((MODES));

1;

##</code><code>##

Dumping MODES: $VAR1 = sub { "DUMMY" };
$VAR2 = sub { "DUMMY" };

##</code><code>##

use constant MODES => ( \ADD_DATA, \REMOVE_DATA );

##</code><code>##

Dumping MODES: $VAR1 = \'add';
$VAR2 = \1;
$VAR3 = \'remove';
$VAR4 = \2;