I want to write something concise and coherent, but it's not happening today :) Instead, assuming you've read the teasers in the Moose manual [1] I'd recommend this [2] interesting comparison of how horizontal code re-use can be achieved in Java, Ruby, PHP and Perl+Moose. There's more philosophical/winding essays on Moose from Chromatic, for example at [3].

Roles/traits/method modifiers/MOP/composability etc. are all great things for getting more reusability... however (and this might sound stupid) the thing that saddens me most when writing Python code is when I find myself adding a bunch of asserts or adding program logic "manually" in situations where I'd normally specify that sort of thing declaratively in a Moose class definition or by referring to a centrally managed Type or delegate stuff through attribute features.

On the other hand, I'm barely into year 2 of full-time Python dev, so perhaps I've yet to find the idiomatic way of doing Python things I used to take for granted in Moose.

Regarding Perl 6, I don't know much about it, except that the original authors of Moose had some inspiration from it.

Is picking up Perl+Moose mind-expanding? It was for me, but I feel that what Moose gave me in Perl was a bit of a band-aid over the fact that it's such a malleable open-ended dynamic language. So as a C++/Java programmer this aspect might not be so enlightening to you, except to see how Moose achieves it in a pretty painless way that I think is very nice and idiomatic for a dynamic language (with the caveats that brings). To put it another way: it gives Perl some of the great benefits of properly declaring things up-front, without the boilerplate/inflexibility pain that I perceive the Java ecosystem's bureaucracy to be (I haven't touched Java for 10 years, so take that with a grain of salt).

If you want to explore some Moose-ish kinds of things within Python, check out [4] (there's another Moose clone in Python that's similarly inactive, sadly) and [5] (Enthought's stuff is perhaps a bit too heavy and incomplete to be the "Moose of the python world", but it gives you a good idea of some of the nice patterns possible when you think outside of the core Python OO featureset).

[1] http://search.cpan.org/dist/Moose/lib/Moose/Manual.pod [2] http://radar.oreilly.com/2014/01/horizontal-reuse-an-alterna... [3] http://modernperlbooks.com/mt/2009/05/perl-roles-versus-inte... [4] https://github.com/frasertweedale/elk [5] http://code.enthought.com/projects/traits/