Jonathan Lang writes: > Larry Wall wrote: > > Well, nothing much really supercedes the class. Even traits have > > to be requested by the class, and if you have an entirely different > > metaclass, it's probably declared with a different keyword than > > C<class>. (But sure, multiple traits will have to applied in order > > of declaration, and I don't doubt there will be ordering dependencies.) > > My apologies; I'm apparently a bit weak on my object-oriented terminology. > I'm not quite sure what's being meant here by "metaclass", other than a > vague concept that it's somehow similar to the relationship between logic > and metalogic. Also, I was under the impression that the writers of the > "tTraits" paper that you referred us to disliked "mixins" largely because > they _did_ use an order-of-precedence conflict resolution scheme; surely > their concerns would apply equally well to what we're calling traits?
I think metaclass is referring to the thing that knows how to associate attributes with their corresponding objects, how do dispatch methods to their corresponding code objects, and whatnot. > > I think the normative way to supercede a class should be to > > subclass it. That's what OO is supposed to be all about, after all. > > If we can keep that orthogonal to role composition, we stand a good > > chance of being able to do a lot of what AOP claims to do without > > the downsides of AOP's own slatheron approach. Or more precisely, > > we can resort to AOP-style wrappers where we really need them, and > > avoid them where we don't. > > As I don't know what AOP is, this is largely lost on me. But I'm all for > keeping various aspects of perl orthogonal to each other if it's > reasonable to do so. Likewise, my main concern isn't so much "how to > supercede a class" as it is "how to keep a class from superceding a role > that it doesn't know about". C<perldoc Aspect> does a pretty good job of introducing one to AOP, at least the extent to which Perl is capable of it (which is quite a lot). > > I'm probably spouting nonsense. I just hope it's good-sounding > > nonsense... > > More importantly, it seems to be _useful_ nonsense. I just hope that _my_ > nonsense is more useful than it is annoying. :) Luke
