In short, I want to invite those who are sufficiently insterested to take a look at and comment on this module. The download link is here. I intend to put the module up on CPAN.

A month ago I put up a meditation Beyond Inside-Out where I sketched a method to do black-box inheritance in Perl without some of the drawbacks of the inside-out technique. The module above is a worked-out version of that sketch. To summarize:

The basis is a function Alter::ego, which retrieves a class-dependent reference associated with an object. A class uses this alter ego for data storage. The Alter::ego and related functions are XS-implemented. The main disadvantage of Alter is that it is an external XS module, while the inside-out technique is pure perl.

The main advantages of Alter over inside-out objects are

An unchanged data model

The alter ego of an object can be any reference. In particular, it can be a hash and the accustomed method of storing object data in hash elements can be maintained. Only now each class gets to see its individual hash.

Garbage collection and thread safety

Perl's normal garbage-collection and thread cloning fully support Alter-based objects. No DESTROY and CLONE methods are required.

Support for Data::Dumper and Storable

Viewing and serializing objects that use out-of-band data storage need support, which Alter provides