wheeler@IDA.ORG (David Wheeler) (06/01/91)
chuck@brain.UUCP (Chuck Shotton):
=I'd like YOU to explain to netland how to support dynamic inheritance at
=runtime in Ada without resorting to manually-supported coding conventions.
=
=I've had a direct hand in the management, design, and implementation of
=about 250,000 lines of Ada over the past 2 or 3 years on NASA's SSE
=contract. We used OOD techniques such as Buhr diagraming, etc. and
=coded according to the design. BUT THAT DOESN'T MAKE THE CODE OBJECT ORIENTED.
=
=The whole point of the comparison between C++ and Ada hinges on the
=semantic interpretation of the term "object-oriented." To most
=Ada-literate individuals, "object-oriented" refers to the concepts of
=information hiding and specific design methodologies. To others (C++,
=academia, etc.) "object-oriented" connotes message passing,
=inheritance, dynamic binding, methods, classes, etc. Ada does NOT
=provide direct support via language constructs and run-time behavior to
=support all of these concepts. The burden is placed on the programmer
=to implement "message passing" and there is no way to safely
=(consistenly) implement dynamic binding.
=
=Rather than degenerate into a "mine's bigger than yours" comparison of
=two vastly different languages (and programming paradigms), it would be
=more constructive to discuss how to implement TRUE object-oriented
=features within the current limitations of Ada. I'd be interested in
=hearing suggestions for supporting the aforementioned list of "alleged"
=object oriented language features using plain vanilla Ada. This could
=actually be useful on some real projects.
There are at least 3 object-oriented extensions(?) to Ada that I know
of: Classic-Ada (SPS in Melbourne, Florida), AOOP (CTA, Rockville, MD;
was APOS), and Dragoon (not sure if this is an extension or merely related).
One of these might be helpful for those who want Ada & OO *now*, but I
only know the names - I haven't used any of them. I don't even know if
they're useful or not. Does anyone have any experience _using_ these
languages?
--- David A. Wheeler
wheeler@ida.org
Disclaimer: this posting never happened.