Re: Anybody in US using ADA ? One silly idea..

[Richard Riehle <richard@adaworks.com>]

"Dmitry A. Kazakov" wrote:

> BTW, did you compare
>
> generic
>    with package Operators is new Generic_Operators <>;
> package Generic_Statistics is ...
>
> with a child package variant:
>
> generic
> package Generic_Operators.Generic_Statistics is ...
>
> It would be interesting to do it in depth.

I'm sure it would be interesting.   However, it changes nothing
with regard to the valuable contribution of generics as one
approach to software reuse.

Bertrand Meyer's observations, in his early paper about
genericity versus inheritance have always made sense to
me.   The two approaches have their own unique benefits.
Sometimes a design is best as a generic component.  Other
times, inheritance is that proper choice.

In these times, inheritance and genericity are no longer the
only choices.   True delegation, as represented by the Ada
keyword, requeue, is another excellent choice.   Child
library units open the door to Aspect_Oriented Programming
in Ada.  Also, Child Library Units make it easier to decompose
a set of methods into specifications that more closely correspond
to high-cohesion.

The object model is just beginning to open itself to a broader
range of collaboration options.   Newer language designs, that
is newer than C++, Ada, Java, or C#, are being developed to
more easily accomodate this broader range of options.   At
present, Ada is pretty good, but it will eventually become as
obsolete as I believe C++ already is.

Even though something is obsolete, people will continue to use
it.   This will be true of Jovial, Ada, C++, and even PL/I.  Yet,
the new range of options demonstrated by the new language
designs will slowly find their way into day-to-day practice.
Some of the features of these languages will come from C++,
some from Ada, and some from other languages.   Perhaps,
someone will adopt the EVALUATE statement from COBOL
in one of these new language designs.

The COBOL EVLUATE statement is one of the most powerful
and linguistically consistent statements ever designed for any
programming language, yet only COBOL has it.   Even so, COBOL
falls far far short of being the ideal programming language.

I don't expect to see the perfect programming language in my
lifetime.   The tone has been set for designing such a language,
but few have accomplished it so far.  Also, as long as those
who have learned one language take a xenophobic attitude
toward any other language that comes on the scene, we will
likely make very little progress.

So, at present, those of us who do write computer programs can
benefit from knowing more than one language and being able to
use each of them for the job where they seem appropriate.  The
DoD tried, and failed, to introduce a single-language policy into
their software projects.   Very likely other such attempts, by
anyone, will also fail.  Even IBM, when it still owned the computer
industry, could not force everyone to adopt PL/I.

Richard Riehle