Even if you're not using an object system, you can still make use of OO concepts.

can() is part of the UNIVERSAL class, which is the base for all objects in Perl. Even though you're not using the object system, you can still call it via PackageName->can('method').

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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