Object Programing and Objective C

[George Williams]

> BTW, anybody have any comments about the incongruity where you can
> "dis-inherit" messages/procedures (by overriding
> them with procedures that print errors) but cannot dis-inherit
> instance variables that, in a certain subclass, lose their usefulness?

I don't know SmallTalk, and am not sure what you are asking but...
In SIMULA there was(is) a concept of HIDDEN/PROTECTED whereby variables
in classes could be hidden from the outside world (as I recall HIDDEN
completely hid the variable, and protected marked it as read-only, but
I could be wrong).  I don't remember how this affected sub-classes, but
it would be pretty easy to add something that does...