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From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Newsgroups: comp.lang.ada
Subject: Re: Generic-Package Elaboration Question / Possible GNAT Bug.
Date: Tue, 22 Nov 2011 22:26:02 +0100
Organization: cbb software GmbH
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Date: 2011-11-22T22:26:02+01:00
List-Id: <comp.lang.ada>

On Tue, 22 Nov 2011 15:03:52 -0600, Randy Brukardt wrote:

> Note that I no longer even try to deal with accessibility checks; I use 
> 'Unchecked_Access (only).

Same with me, but since Ada 2005 I tend to use 'Access again, because it
works so much better in Ada 2005.

> OTOH, dynamic checks like overflow checks and index checks are not evil,

Sure, I meant only dynamic checks of *program correctness*. Overflow or
index are not such checks, they are here to enforce defined, contracted
behavior.

Pre-/post-conditions and accessibility checks pretend [only pretend] to be
correctness checks, yielding true if the program is correct. As the result
the user expects them not to raise exceptions and is programming the rest
correspondingly. That is a wrong idea, which makes programs less safe due
to false expectations. It is same as reading file and expecting that
End_Error is never raised. I want that exception expectations were
contracted and checked statically. If impossible to prove, the program
should only be legal if it is *visibly* annotated as potentially raising
the corresponding exception.

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