Re: Interesting but sensitive topic to discuss (HELP: - OOP and CASE tools)

[Alan Lovejoy <alovejoy@concentric.net>]

Jan Steinman wrote:
> 
> In article <32875B03.3729@iconcomp.com>, bill@iconcomp.com wrote:
> 
> > Alan Lovejoy wrote:
> > >
> > > I think you've hit the nail on the head.  I do distinguish between
> "design" and "coding".
> > >
> > > To me, the "design" of a program is a language-independent
> abstraction.  Implementation
> > > inheritance is a coding issue....
> >
> > I'd like to hear more about how you think design can be done
> > independent of language, and what such a "design" would look
> > like...
> 
> The biggest disasters I've seen were designed with the philosophy that the
> implementation vehicle was unimportant. (In fact, the January issue of The
> Smalltalk Report is rumored to have a column on this very topic... :-)
> Conversely, the most successful projects I've seen were ones where the
> designers were well-versed in the implementation language.
> 
> I think it is necessary for the designer to understand -- if not excel in
> -- the implementation vehicle. "Real" architects study civil engineering
> as well as architecture, or else they might design a skyscraper made of
> wood and paper.

My usage of the word "design" in the quote above is being interpreted in a way
other than I intended.  In the context of the earlier posts, it should have been
clear that by "design" I was referring to the objects that exist when the program 
runs, and how they interact.  And I was **defining** the term design as I had
used it, not trying to suggest that the implementation technology is not important,
or that one should not consider such issues when producing a design or implementing
a system!

For a design to be "language independent", it is sufficient that it be implementable 
in any language.  Whether it would be the optimal implementation in each language
is a different (although admittedly important) issue.

So I actually agree with your thesis.

> > I think it is impossible to progress very far from a domain
> > model into design without considering target language...
> 
> Here here!

Well, not **impossible**, just ill-advised.

> > > * When should delegation be used instead of inheritance?
> 
> Hmmm... how do you accomplish *that* in a language independent manner?

Again, I did not suggest that you should.

> Turn it over to a C++ coder, they might consider multiple inheritance,
> turn it over to a Smalltalker, they're going to think of general
> delegation.

Of course.  But the methodology should deal with this issue, and give the right 
answer for each language--or perhaps suggest that the wrong implementation language
is being used for the problem at hand.

> Programming is still a combination of art, craft, and science. Most
> methodologies I've encountered try to force programming entirely into the
> "science" realm. I think that is a mistake.

Yes, but the goal of scientific rigor is a good one.  Recognizing that we aren't
there yet can only be healthy, whether one is a methodology user or a methodology
researcher.

--
Alan L. Lovejoy		|==============================================| 
Smalltalk Consultant	|	Beware of Geeks bearing GIFs!	       |
alovejoy@concentric.net |==============================================|