ambiguous inheritance question

Ivan Moore ivan at cs.man.ac.uk
Wed Jan 25 19:26:16 UTC 1995


Dear Self interest group,

What are peoples opinions on the following:

given an inheritance hierarchy as below:

               A
              / \
             B   C
              \ /
               D

where B and C are parents of D, and A is the parent of B and C,

If A defines slot m, and B defines its own version of slot m, if you send D 
the message m, you get an ambiguous selector error (as expected).

How about if D got the m in B, because it does override the one in A,
after-all. What I mean is that the m in B overrides the very same slot m that D
inherits via C. If it was a different m that it was overriding I'd be totally
happy with an ambiguous selector error.

What do you think? Would the proposed scheme invite obscure bugs? Would it
be difficult to understand? You may think that this sort of situation doesn't
occur often enough to be a problem - maybe true - but dispite that, what do
you think?

Ivan.




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