> On Thu, 9 Jan 2003 16:40:20 -0500, Dan Sugalski wrote: >> #10 We do MI, but we don't instantiate a class' attributes multiple >> times if its in the hierarchy for a class more than once. If it is, >> the leftmost instance is real, the rest are virtual
My only question here is: What is leftmost? Is that the same as "closest to the actual class we're looking at" or is it "first time it appears in the inheritance structure, and thus the furthest from the relevant class" ? (or something else entirely?) > This will mean we can't support Eiffel, which allows repeated real > inheritance of the same class. It does this by allowing renaming at the > feature level (thats attributes and methods in perl) when inheritance is > declared. Repeated inherited features are shared if they keep the same > name (and they really are the same feature), or split if they don't. I'll admit to never having gotten to looking at eiffel, just hearing about it from some other folks ... But what is the point of explicitly inheriting from the same class multiple times? I mean, sure, if it's in the inheritance tree multiple times, fine, but then you ignore most of them generally; what benefit/use comes from having it actually be in the tree multiple times as distinct entities? I'm just wondering there ... But if it's renaming the structure anyway, wouldn't it still be possible with the single-MI structure that dan proposed? as in, if B inherits from A and then C inherits from A and B directly (and assuming there's a need to separately retain the individual inheritance directions), wouldn't the compiler then say that B inherits from A and C inherits from A2 and B, to retain them both in the parrot? --attriel (I could, of course, be horribly wrong, had I stated a firm opinion rather than requests for more information :)
