Re: But is it Object-Oriented?

> I'm not convinced that the model is broken. 
I can tell ;-)

All I can say is that my experience learning Nice has been very
different from what you suppose to be the case. (And contrasts badly
with my experience learning Clean. I find pure functional programming
quite a challenge to my thinking, and yet I've never felt misled by
Clean.)


> Say we start with Java methods... We did not break any previous 
> model, we just made it more general.

We've created a fiction that the compiler reveals to be a fiction
everytime it flags an ambiguous method. There isn't a way to make sense
of compiler error messages using the fiction that Nice is like Java.
Been there, done that.

> I don't see where we have broken the initial model. We have evolved
> it with several steps of "you can do more" and "this is actually a
> special case of that".

We also took something away. Something quite fundamental to the
ordinary view of OO: a class encapsulates methods. 

This is quite clear: in Nice a 'private' method encapsulated in a class
is not 'private' to that class. 

This is quite clear from other language designs which promote
"encapsulated multimethods", for example Half & Half. 
http://www.cis.ohio-state.edu/~gb/Brew/Publications/HalfNHalf.pdf

Note: I'm not suggesting that Nice should use encapsulated multimethods
- rather given that we only have multimethods (and functions) in Nice
we should avoid misleading newbies with the idea that there are any
encapsulated methods in Nice.


> >There's no point expecting experienced developers to revise their
> >notion of what a class and interface is 

> Other languages have differing notions of what a class or a method
> is. For instance, C++ classes can inherit from several classes while
> Java classes cannot. The important thing is that there you can
> relate the two, and just remember this difference. I have shown
> above that you can do the same between Java methods and Nice methods.

And AFAIK in both C++ and Java, a class encapsulates methods - this is
one of the few common threads in OO.


> And in Nice the problem is even non-existent, because it is
> generalizing the concepts, not restricting them.

I disagree. In Nice, the class no longer encapsulates methods - that is
not a generalization of OO, it's a fundamental departure.

best wishes, Isaac

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