While I am still amazed of the power and flexibility of Perl's own OO system, I'm at least as amazed of what Moose got out of it.

Sometimes there is too much flexibility.

Moose is built on Class::MOP, which implements a meta-object protocol. The MOP lays out a well-defined abstraction for the components of an object system and how they are supposed to behave and interact. That well-defined abstraction is what the Perl object system lacks, so Class::MOP builds one on top of the Perl object system and has it provide the API for things like Moose.

Many kudos for stvn for his work on it. (And more kudos for his explaining the MOP to me at YAPC in simple words I could understand.)

For more on MOP:

• The Art of the Metaobject Protocol (book)
• metaobject protocol (Google)

Sometimes there is too much flexibility.

Moose is built on Class::MOP, which implements a meta-object protocol. The MOP lays out a well-defined abstraction for the components of an object system and how they are supposed to behave and interact. That well-defined abstraction is what the Perl object system lacks, so Class::MOP builds one on top of the Perl object system and has it provide the API for things like Moose.

I respectfully but hardly disagree. Without the flexibility, we'd have one solution. Maybe it would be like Moose, maybe it would be another. But it certainly couldn't evolve in the way it does. So, for my part: Hooray for flexibility.

YMMV.

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Ordinary morality is for ordinary people. -- Aleister Crowley

Without the flexibility, we'd have one solution

This is not about black or white. MOP doesn't eliminate flexibility, it just defines an interface around it.

-xdg

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