my @package-ish = do given Metamodel {
    $_<
       PackageHOW
       ModuleHOW
       ClassHOW
       GrammarHOW
       CurriedRoleHOW
       ConcreteRoleHOW
       ParametricRoleHOW
       ParametricRoleGroupHOW
      >;
}

sub is-package($object) is export {
    !$object.defined && $object.HOW ~~ any @package-ish;
}

# These are package-like objects. Not sure if Nil should count or not.
do .&is-package for class {}, package {}, role {}, IO, Int, GLOBAL, Proc, X, Nil;

# These are not packages
do .&is-package for "", 7, [], {}, /asdf/, &substr, :(Int, Str), \(1, 2, 3);