Re: Clean Object Class Design -- Circle/Ellipse

Graham Perkins <gperkins_at_dmu.ac.uk> wrote in message news:<3BC56D0A.BC80A70A_at_dmu.ac.uk>...
> Bob Badour wrote:
> > ..
> > If Smalltalk made sufficient distinction between values and variables
>
> It makes perfect such distinction.

I disagree, and I have explained exactly how it makes insufficient distinction.

> > one would not need to override setFoci in the Circle class because it
> > would never inherit the method. Circle values would inherit the
> > operations on Ellipse values but Circle variables would not inherit
> > the operations on Ellipse variables.
>
> Oh you really are confused. I can see where now, but not
> sure if I can explain it.

If you were correct instead of confused yourself, you would have no doubt of your ability to explain it. As I observed earlier, I believe Smalltalk is the programming language equivalent of Newspeak. Smalltalk programmers seem to lose the ability to conceive or to communicate programming fundamentals.

> However, the solution which would remove your problem would be
> to clearly distinguish between mutable and immutable objects.

In other words, programmers must resort to ad hoc idioms and patterns because Smalltalk makes inadequate distinction between values and variables.

> It's a matter of how you design the classes, and absolutely nothing
> to do with any particular issues of variables and values in Smalltalk
> or any other language.

I disagree. It's a matter of how well the language reflects reality and of how well the language supports the type modeller in his or her task. Received on Thu Oct 18 2001 - 02:11:42 CEST