Seems Moose allows you to attach roles to instances, not just classes, with Moose::Util::apply_all_roles($applicant, @roles) by creating a new anonymous class with the object's previous class as superclass and with the roles applied, and then reblessing the object into that class. Not sure the other role implementations have easily accessible methods to do this.
in reply to Re: a State machine with Roles - possible? (class or instance)
in thread a State machine with Roles - possible?
UPDATE: using Moo::Role or Role::Tiny this seems to work bless $object, Moo::Role->create_class_with_roles(blessed $object, @roles); (replace Moo::Rule with Rule::Tiny for less Moo-ness, and import blessed from Scalar::Util)