From: Robert A Duff <bobduff@shell01.TheWorld.com>
Subject: Re: Exceptions
Date: Thu, 13 Dec 2007 08:40:34 -0500
Date: 2007-12-13T08:40:34-05:00 [thread overview]
Message-ID: <wccejdqzp9p.fsf@shell01.TheWorld.com> (raw)
In-Reply-To: 4dae26fe-0c8a-46e1-9a33-43c18cf757ae@i3g2000hsf.googlegroups.com
Maciej Sobczak <see.my.homepage@gmail.com> writes:
> On 11 Gru, 09:07, Stephen Leake <stephen_le...@stephe-leake.org>
> wrote:
>
>> For code I have control over, I agree with Bob, except I use a
>> different exception; raise Programmer_Error if you've detected a bug.
>
> I understand that this way you want to signal something much more
> severe than "mere" Constraint_Error or such.
> The problem is that Program_Error can be shut up by some null handler
> or it can be translated to some other exception and then lose its
> original weight.
The solution to "when others => null;" and the like is better
education. Competent programmers need to know not to do that,
except in rare cases, where a big fat comment is in order.
(Unfortunately, the designers of Ada 83 made exactly this
mistake for task bodies! And Ada 95 repeats it for
interrupt handlers.)
I don't consider Constraint_Error "mere", by the way.
It almost always represents a bug.
> Why not terminating the program right on the spot by simply:
>
> pragma Assert (False);
>
> ?
That doesn't terminate the program on the spot.
It raises Assertion_Failure.
I consider all of these:
pragma Assert (False);
Assert (False); -- Assert is a user-defined procedure
raise Program_Error;
raise Bug; -- Bug is a user-defined exception used project-wide
to be legitimate ways of reporting a self-detected bug.
There ought to be a standard predefined procedure for stopping the
program "on the spot". Since there isn't, you can import "exit".
> (yes, there are compiler options to switch it off as well)
Indeed, it's turned off by default in GNAT (which I don't much like).
> Does anybody use this strategy in regular code?
> I happen to use it in test units and I find it very appropriate there.
> Any thoughts on using assertions, including Assert(False), in
> production code?
Nothing wrong with using assertions in production code.
- Bob
next prev parent reply other threads:[~2007-12-13 13:40 UTC|newest]
Thread overview: 100+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-12-06 15:00 Exceptions shaunpatterson
2007-12-06 21:24 ` Exceptions tmoran
2007-12-07 8:54 ` Exceptions Dmitry A. Kazakov
2007-12-07 10:21 ` Exceptions Georg Bauhaus
2007-12-07 15:11 ` Exceptions shaunpatterson
2007-12-07 16:08 ` Exceptions Gautier
2007-12-07 18:56 ` Exceptions Simon Wright
2007-12-08 10:04 ` Exceptions Stephen Leake
2007-12-08 3:30 ` Exceptions Randy Brukardt
2007-12-08 10:09 ` Contracted exceptions for Ada (was: Exceptions) Dmitry A. Kazakov
2007-12-09 10:22 ` Contracted exceptions for Ada Stephen Leake
2007-12-09 11:02 ` Dmitry A. Kazakov
2007-12-11 8:10 ` Stephen Leake
2007-12-11 10:36 ` Dmitry A. Kazakov
2007-12-09 15:11 ` Contracted exceptions for Ada (was: Exceptions) Martin Krischik
2007-12-09 17:36 ` Contracted exceptions for Ada Dmitry A. Kazakov
2007-12-09 18:39 ` Simon Wright
2007-12-10 8:19 ` Dmitry A. Kazakov
2007-12-10 20:25 ` Simon Wright
2007-12-11 8:50 ` Dmitry A. Kazakov
2007-12-11 20:50 ` Simon Wright
2007-12-12 10:20 ` Dmitry A. Kazakov
2007-12-09 19:04 ` Martin Krischik
2007-12-10 8:20 ` Dmitry A. Kazakov
2007-12-09 22:09 ` Robert A Duff
2007-12-10 7:09 ` Stefan Lucks
2007-12-10 16:57 ` Robert A Duff
2007-12-11 1:53 ` Contracted exceptions for Ada (was: Exceptions) Randy Brukardt
2007-12-11 9:16 ` Contracted exceptions for Ada Dmitry A. Kazakov
2007-12-12 0:26 ` Randy Brukardt
2007-12-08 12:26 ` Exceptions Peter C. Chapin
2007-12-08 14:01 ` Exceptions Dmitry A. Kazakov
2007-12-08 18:01 ` Exceptions Peter C. Chapin
2007-12-09 10:06 ` Exceptions Dmitry A. Kazakov
2007-12-09 12:40 ` Exceptions Peter C. Chapin
2007-12-09 14:31 ` Exceptions Dmitry A. Kazakov
2007-12-09 16:38 ` Exceptions Peter C. Chapin
2007-12-10 8:31 ` Exceptions Dmitry A. Kazakov
2007-12-09 21:56 ` Exceptions Robert A Duff
2007-12-09 10:24 ` Exceptions Stephen Leake
2007-12-09 12:46 ` Exceptions Peter C. Chapin
2007-12-09 21:39 ` Exceptions Robert A Duff
2007-12-09 22:13 ` Exceptions Georg Bauhaus
2007-12-11 8:07 ` Exceptions Stephen Leake
2007-12-11 20:28 ` Exceptions Simon Wright
2007-12-12 22:10 ` Exceptions Maciej Sobczak
2007-12-13 13:40 ` Robert A Duff [this message]
2007-12-13 14:00 ` Exceptions Maciej Sobczak
2007-12-13 14:44 ` Exceptions Robert A Duff
2007-12-14 0:46 ` Exceptions Ray Blaak
2007-12-14 2:36 ` Exceptions Randy Brukardt
2007-12-14 6:21 ` Exceptions Ray Blaak
2007-12-14 12:40 ` Exceptions Georg Bauhaus
2007-12-14 17:29 ` Exceptions Robert A Duff
2007-12-14 19:32 ` Exceptions Dmitry A. Kazakov
2007-12-15 5:29 ` Exceptions Ray Blaak
2007-12-13 19:29 ` Exceptions Randy Brukardt
2007-12-12 19:18 ` Exceptions Martin Krischik
2007-12-13 13:27 ` Exceptions Robert A Duff
2007-12-13 23:25 ` Exceptions Ray Blaak
2007-12-06 21:25 ` Exceptions Gautier
2007-12-07 4:29 ` Exceptions anon
2007-12-07 4:43 ` Exceptions, part 2 anon
2007-12-07 16:55 ` Exceptions Adam Beneschan
2007-12-07 18:59 ` Exceptions Simon Wright
2007-12-08 0:38 ` Exceptions Adam Beneschan
2007-12-09 21:45 ` Exceptions Robert A Duff
2007-12-09 22:40 ` Exceptions Georg Bauhaus
2007-12-10 8:22 ` Exceptions Dmitry A. Kazakov
2007-12-10 9:20 ` Exceptions Georg Bauhaus
2007-12-10 9:30 ` Exceptions Georg Bauhaus
2007-12-10 10:56 ` Exceptions Dmitry A. Kazakov
2007-12-11 2:18 ` Exceptions Randy Brukardt
2007-12-11 8:19 ` Exceptions Georg Bauhaus
2007-12-11 11:55 ` Exceptions Dmitry A. Kazakov
2007-12-11 16:13 ` Exceptions Georg Bauhaus
2007-12-12 11:18 ` Exceptions Dmitry A. Kazakov
2007-12-10 12:09 ` Exceptions Niklas Holsti
2007-12-10 13:08 ` Exceptions Dmitry A. Kazakov
2007-12-10 20:02 ` Exceptions Niklas Holsti
2007-12-11 12:31 ` Exceptions Dmitry A. Kazakov
2007-12-11 13:21 ` Exceptions Niklas Holsti
2007-12-12 0:01 ` Exceptions Randy Brukardt
2007-12-12 11:37 ` Exceptions Niklas Holsti
2007-12-12 13:14 ` Exceptions Dmitry A. Kazakov
2007-12-12 14:37 ` Exceptions Robert A Duff
2007-12-13 19:20 ` Exceptions Randy Brukardt
2007-12-13 20:15 ` Exceptions Robert A Duff
2007-12-12 11:00 ` Exceptions Dmitry A. Kazakov
2007-12-11 2:12 ` Exceptions Randy Brukardt
2007-12-11 15:17 ` Exceptions Robert A Duff
2007-12-12 0:10 ` Exceptions Randy Brukardt
2007-12-13 19:58 ` Exceptions Robert A Duff
2007-12-14 0:53 ` Exceptions Ray Blaak
2007-12-14 2:48 ` Exceptions Randy Brukardt
2007-12-14 6:33 ` Exceptions Ray Blaak
2007-12-08 10:03 ` Exceptions Stephen Leake
-- strict thread matches above, loose matches on Subject: below --
1991-03-06 17:24 Exceptions David Erickson
1991-03-06 21:21 ` Exceptions Jerry Callen
1989-06-23 21:57 Exceptions howell
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