How do I use a Perl package known only in runtime?

Question

I have a Perl program, that needs to use packages (that I also write). Some of those packages are only chosen in Runtime (based on some environment variable). I don\'t want

Answer 1

I would use UNIVERSAL::require. It has both require and use methods to use a package. The use method will also call import for the package.

use UNIVERSAL::require;
$ENV{a}->use or die 'Could not import package:  ' . $@;