Darren New <dne### [at] sanrrcom> wrote:
> >   Then they are not object-oriented languages. Some kind of inheritance is
> > a basic feature of object-oriented languages.

> This isn't correct. There are, for example, delegation-based OO 
> languages, wherein you say "Anything I don't handle, that other class 
> over there handles", but it's not an inheritance heirarchy as such. It's 
> merely delegation.

  Who defines that object-orientedness may not have inheritance?

  The "is-a" (and "has-a") relation between classes is a fundamental
property of object-orientedness.

> No, this is not correct. While it's true that most popular 
> object-oriented languages support inheritance, you can have OO languages 
> without inheritance.

  In what basis can you call it an OO language?
  Having modules is not sufficient.

> Imagine Java with no inheritance of functions, only "inheritance" of 
> what java calls interfaces. Does it stop being "object oriented"? Most 
> people working in the field of designing programming languages I think 
> would say "no, it's still OO".  It still has objects, dynamic dispatch, 
> memory management, classes, instances, etc. Just not inheritance.

  If you inherit class X from class Y you are saying "X is a Y" (that is,
it implements everything Y implements and behaves like Y).
  Y may be completely abstract, meaning that it does not implement anything
itself. However, deriving a class from it still means that the derived
class "is a Y".
  If you make a class which implements an interface you are doing inheritance.
Limited perhaps, but still inheritance.

  (By the way, what does memory management have to do with OO?)

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