use Safe;
$cpt = new Safe;  # create a new safe compartment
*****
$cpt = new Safe;
sub wrapper {
    ;# vet arguments and perform potentially unsafe operations
}
$cpt->share('&wrapper');  # see share method below
*****
$cpt = new Safe NAMESPACE, MASK;
*****
$cpt = new Safe 'Root';
$Root::foo = "Hello world";
# Equivalent version which doesn't need to know $cpt's package name:
${$cpt->varglob('foo')} = "Hello world";