MapMaker

• stolen from an app, will CPAN it soon
• you can do similar things

package MapMaker;
use Moose;
use Moose::Util::TypeConstraints;

sub other { return 'right' if shift eq 'left'; return 'left' }

coerce 'ClassName' => from 'Str' => via { Class::MOP::load_class($_); $_ };