Good, because without specifying the methods to implement, why have an abstract class?

My point was that inheriting and checking the existance and signatures (if possible, which doesn't appear to be the case in Perl5) should be the only things abstract classes force on subclasses. Sorry if I wasn't clear.

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I wanted to explore how Perl's closures can be manipulated, and ended up creating an object system by accident.
-- Schemer

Note: All code is untested, unless otherwise stated