Re: ANN: Units of measurement for Ada v 3.4 released

["Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>]

On Wed, 11 Jun 2014 11:25:17 -0700 (PDT), Dan'l Miller wrote:

> On Wednesday, June 11, 2014 4:37:13 AM UTC-5, Dmitry A. Kazakov wrote:
>> On Tue, 10 Jun 2014 12:13:42 -0700 (PDT), Dan'l Miller wrote:
>>> Also, revealing which severe roadblocks (if any) that you hit using
>>> Ada2012 in bringing this library to fruition as this flower blossoms would
>>> be interesting to fix in Ada202X.
>> 
>> It is kept compilable with Ada 2012. The things which could improve it are
>> compile-time discriminant expressions and mandatory removal of static
>> discriminants. I don't see them coming anytime soon in Ada.
> 
> http://www.ada-auth.org/ais.html
> Why not?  Have you made the case in officially-submitted Ada Issues (AIs)? 
> Why let Ada languish unimproved when you as an expert (with demonstrable
> concrete examples from in-use libraries) know how to make Ada better?

Because writing such complex proposal is beyond my knowledge and power.
There is a huge distance between mere an idea (programmer's woe) and its
implementation in the form of AI (language design).

Furthermore AI platform is completely unsuitable for big changes. AI is for
minor patches.

And it will never be accepted anyway.

>> It is difficult to say if language design driven by libraries is good or
>> bad. STL influenced C++ before Boost.
> 
> http://en.wikipedia.org/wiki/Standard_Template_Library#History
> Alexander Stepanov wrote the initial versions of STL in Ada.  C++1998 was
> heavily influenced by that Ada work to bring C++'s feature-set on parity
> with Ada.

That is because only Ada had generics that time. Stepanov mistakenly
thought that generics were a way to go.

Templates did no good to C++, generics did even less to Ada. Parametric
polymorphism is corroding to the language structure. It was understandable
in 80's to add generics to the language because the alternative was a
preprocessor of C or PL/1 fashion.

Ada should have rid of generics in 95 when proper dynamic polymorphism was
introduced and concentrate efforts on static checks to eliminate dispatch
and tags/discriminants in static cases (the realm of generics, static
polymorphism).

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de