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From: crispen@eight-ball.boeing.com (crispen)
Newsgroups: comp.lang.ada
Subject: Re: ada software reuse
Message-ID: <9303221623.AA26836@eight-ball.boeing.com>
Date: 22 Mar 93 16:23:38 GMT
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Organization: The Internet
Date: 1993-03-22T16:23:38+00:00
List-Id: <comp.lang.ada>

wdvs@uunet.uu.net  (Terminal Boredom) asks:

>Can anyone please explain how ADA supports the concept of software reuse,
>including how ada supports this concept.

Well, the ADA (Americans for Democratic Action) was (is?) an
organization which supplied ratings on Congressmen and Senators on
how closely they adhered to the "liberal Democratic" party line in
their voting behavior.  Thus, Teddy Kennedy could be expected to
have a higher ADA rating than Jesse Helms.

I'm sorry to report that ADA has, to my knowledge, never taken a
position on software reuse, though one could certainly say that
reuse is quite a conservative undertaking (but, since the SEI
thinks that reuse has nothing to do with maturity, one could argue
just as convincingly that it's radical ;-)

Ada, on the other hand, facilitates software reuse by such concepts
as packages, generics, and abstract typing and by the simple, powerful
fact that it's a standardized language without significant varieties.

I haven't got a clue as to what "ada" is.

Sorry for the smart-ass reply, but I suspect that your question
isn't susceptible to a simple, brief answer.  I presume you're
already aware of the Software Productivity Consortium's Synthesis
process for reuse, and the STARS Megaprogramming concept, as well
as the Software Engineering Institute's Structural Modeling work
and ARPA's Domain Specific Software Architecture project.  If not,
I'd suggest you check out some of the papers.  I've contributed in
a very minor way myself.

I contend (and I am not by the wildest stretch of the imagination
original in this) that reuse requires at least: (a) a mechanism for
capturing domain knowledge, (b) a process for extracting that
knowledge in the form of adapted components, and (c) an adaptable
architecture, specific to the problem domain, on which those components
can hang (though the architecture may well be an instantiation of
"eternal verity" architectural principles).  People knowledgeable about
reuse do not agree on all these points.

If one has the understanding of the mechanisms of Ada that can be
obtained from a couple of 40-hour courses (provided one is directed
toward software engineering principles in those courses) it will
become apparent how Ada facilitates each of those elements of
reuse.
+-------------------------------+--------------------------------------+
| Bob Crispen                   |   Who will babysit the babysitters?  |
| crispen@foxy.boeing.com       +--------------------------------------+
| (205) 461-3296                |Opinions expressed here are mine alone|
+-------------------------------+--------------------------------------+