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From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Newsgroups: comp.lang.ada
Subject: Re: Ada package registry?
Date: Fri, 5 Feb 2016 09:59:53 +0100
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Date: 2016-02-05T09:59:53+01:00
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On 04/02/2016 22:09, Randy Brukardt wrote:
> "Björn Lundin" <b.f.lundin@gmail.com> wrote in message
> news:n8vvfk$ml3$1@dont-email.me...
>> On 2016-02-03 23:11, Randy Brukardt wrote:
> ....
>> I note that you do not mention working with relation databases.
>> If you work with them, it's hard to avoid c-bindings .
>
> I personally think databases are WAAAAY overused.

Yes

> For a lot of projects,
> some sort of Ada persistent storage is a better solution. The problem in the
> past has been that such storage couldn't be abstracted very well, so one
> typically has built something custom. Ada 2012 has enough syntactic sugar
> that persistent storage libraries (like containers) should be reasonable to
> construct abstract systems that are still reasonably easy to read and write.

Well, I disagree. Ada still lacks some key features to have types like 
relational tables declared. There is no way you could do that even with 
generics (which have no use for a persistent storage anyway). But even 
with generics you cannot do:

generic
    type Column_1 is private;
    type Column_2 is private;
    ...
    type Column_n is private;

For dealing with relational algebra you need introspection and 
containers of any-non-limited type.

> (The reason that we adopted the generalized reference feature that we did is
> because of the ability to use it to manage persistence -- in particular, to
> be able to figure out when the in-memory copy can be freed and written to
> the backing store.)

That is not enough. You need references with a notification upon 
dereferencing.

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