Darren New <dne### [at] sanrrcom> wrote:
> Warp wrote:
> > Darren New <dne### [at] sanrrcom> wrote:
> >> That's certainly part of it, but you don't need to support multiple 
> >> inheritance in the same way C++ does it.  Eiffel has multiple inheritance, 
> >> garbage collection, and O(1) virtual dispatch.  (That last would probably be 
> >> quite difficult if you didn't compile everything at the same time, of course.)
> > 
> >   As I have mentioned before, you can cast an object pointer to an
> > incompatible type assuming that:

> Right.  I'm not sure what that had to do with what I was saying.

  Nothing. Not everything has to be a direct answer to what has been written.
It's chatter.

> I believe the mechanism relies on knowing at compile time what every class 
> in the system will be.

  You mean it doesn't support precompiled libraries? (Why does that seem to
be so common with "higher-level" languages?)

> >   I wonder if Eiffel supports this as well.

> Eiffel lets you cast up and down the heirarchy. All methods are semantically 
> virtual (even if the compiler optimizes them to direct jumps), so the fact 
> that you're casting up and down doesn't make it "invalid". You can't cast a 
> reference to an object to a type that isn't in that object's parent class 
> heirarchy.

  Does that mean "no"?

  Note that in the case I was talking about you are not casting only up or
only down in the hierarchy. You are actually casting down and then up in one
go (in a multiple inheritance situation), without seeing any of the
intermediate classes directly.

-- 
                                                          - Warp

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