use strict;
use warnings;

use List::Util      qw( max );
use Variable::Magic qw( cast wizard );

# Make $x a magical variable that always returns 5.
cast(my($x),
   wizard(
      get => sub { ${ $_[0] } = 5 },
   )
);

$x = 3;

if ($ARGV[0]) { no warnings 'void'; 0+$x }

print('max($x, 4)=', max($x, 4), "\n");
print('$x=', $x, "\n");