In article <40394a33@news.povray.org>, Warp <war### [at] tagpovrayorg> 
wrote:

>   What do you mean "no virtual functions"? If every function is dynamically
> bound, then *every* member function is virtual.

No. Virtual function tables are an implementation detail, the 
implementation specifically used by C++. There are other ways of 
implementing dynamic dispatch.


> > Again, I'm talking about single inheritance. Multiple inheritance is not 
> > necessary, and is needlessly complex.
> 
>   Who is talking about multiple inheritance here? I'm not.

You're implying it. You say abstract classes can replace interfaces. A 
class can have multiple interfaces, but in single interface models can 
only inherit from one class. Therefore, I figured you must be talking 
about multiple inheritance, because nothing else made sense.


>   And multiple inheritance may be complex from the point of view of
> the interpreter/compiler, not from the point of view of the user.
> Why should that be a limit?

Look at virtual inheritance and why it's necessary.


>   I don't understand what you are saying.
>   Why have *two* types of classes when you can have just one?

I never said anything about two class types...I have no idea how you're 
reading what I'm trying to say. 


> And why abstract classes are not useful in single inheritance model?

Because you can only inherit from one.


> > Interfaces render multiple inheritance + multiple abstract root classes 
> > obsolete, not the other way around.
> 
>   Interfaces are a poor way of making multiple inheritance. They have
> all the logical problems of multiple inheritance and they force you
> to make code repetition.

They do not have all the problems of multiple inheritance. And a 
language could have default implementations for interfaces. Java is not 
an example of a perfect, or even very good OO language.


>   I have never understood what's so good about interfaces.

They avoid many of the problems of multiple inheritance.

-- 
Christopher James Huff <cja### [at] earthlinknet>
http://home.earthlink.net/~cjameshuff/
POV-Ray TAG: <chr### [at] tagpovrayorg>
http://tag.povray.org/

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