Hello

While discussing the implementation of Net::LDAP::Express on the perl-ldap list, I had a short discussion with Graham Barr:

GB: If there is one thing that concerns me is that it is implemented by inheritance. inheritance is usually, in my experience, used to extend functionality of a class. But in this case you are changing it.

Me: I realized that I needed all functionalities of Net::LDAP that I didn't reimplement, and I thus had to proxy every unknown method back to Net::LDAP. That called for my module to be a subclass rather than a "composition".

GB: You need to use delegation for those methods. See Class::Delegation

Since then I started to meditate about the pros and cons of inheritance and delegation; in particular I started asking myself why and how inheritance could be evil.

Anyone that can help me to boost my meditations on the subject?

Thanks a lot in advance

Ciao!
--bronto

PS: Not sure if this is a Meditation or SOPW, let's see what editors think :-)

The very nature of Perl to be like natural language--inconsistant and full of dwim and special cases--makes it impossible to know it all without simply memorizing the documentation (which is not complete or totally correct anyway).
--John M. Dlugosz

In reply to Inheritance vs Delegation: pros and cons by bronto

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