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From: "Randy Brukardt" <randy@rrsoftware.com>
Newsgroups: comp.lang.ada
Subject: Re: What would you like in Ada202X?
Date: Wed, 25 Apr 2012 21:08:06 -0500
Organization: Jacob Sparre Andersen Research & Innovation
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Date: 2012-04-25T21:08:06-05:00
List-Id: <comp.lang.ada>

"Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> wrote in message 
news:mdgi0fhwon01$.18b871w98pjl6.dlg@40tude.net...
...
> There is no means to flatten P making declarations of Q be directly 
> visible
> for clients of P. E.g. something like
>
>   package P is
>      package Q is new Foo (...);
>      use all Q; -- Make things from Q declared directly in P
>   end P;

We tried to do this for Ada 2012; we made heroic efforts to do so. The 
problem is, this feature is a massive potential maintenance problem which 
destroys most of the Ada concepts of visibility and maintainablity. (It's 
all of the mistakes of package "use" multiplied a hundred-fold.)

The biggest problem comes when there is a conflict between things declared 
in P and things declared in Q. Resolving that proved impossible without 
introducing major headaches.

In the end, we abandoned it as just being too complex. That's too bad, 
because it *seems* important.

Some of the attempts can be found in AI05-0135-1 and AI05-0135-2.

I'd like to think that we explored every possible solution, and none of them 
work. Perhaps someone can find a solution that we didn't explore, but in the 
absence of that, I don't see a feature like this ever flying in Ada.

                                         Randy.