On 11/18/2013 04:58 PM, Christopher Armstrong wrote:
On Mon, Nov 18, 2013 at 3:00 PM, Dan Smith <d...@danplanet.com <mailto:d...@danplanet.com>> wrote:Sorry for the delay in responding to this... > * Moved the _obj_classes registry magic out of ObjectMetaClass and into > its own method for easier use. Since this is a subclass based implementation, > having a separate method feels more appropriate for a factory/registry > pattern. This is actually how I had it in my initial design because I like explicit registration. We went off on this MetaClass tangent, which buys us certain things, but which also makes certain things quite difficult. Pros for metaclass approach: - Avoids having to decorate things (meh) - Automatic to the point of not being able to create an object type without registering it even if you wanted to Cons for metaclass approach: - Maybe a bit too magical - Can make testing hard (see where we save/restore the registry between each test) - I think it might make subclass implementations harder - Definitely more complicated to understand Chris much preferred the metaclass approach, so I'm including him here. He had some reasoning that won out in the original discussion, although I don't really remember what that was. It's almost always possible to go without metaclasses without losing much relevant brevity, and improving clarity. I strongly recommend against their use.
++ -jay _______________________________________________ OpenStack-dev mailing list OpenStack-dev@lists.openstack.org http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
