From: "Nasser M. Abbasi" <nma@12000.org>
Subject: Re: about the new Ada 2012 pre/post conditions
Date: Wed, 27 Jun 2012 08:41:55 -0500
Date: 2012-06-27T08:41:55-05:00 [thread overview]
Message-ID: <jsf2j2$iif$1@speranza.aioe.org> (raw)
In-Reply-To: 2klq69d4qqsp$.veefi8i6jnwa.dlg@40tude.net
On 6/27/2012 7:19 AM, Dmitry A. Kazakov wrote:
>
>> A:
>> if Pre (...) then
>> A (X) := 1;
>> else
>> raise Assertion_Failure;
>> end if;
>>
>> B:
>> A (X) := 1;
>>
>> A and B can be shown to both be implementations of the behavior
>> that some contract stipulates.
>> A and B have *essentially* the same effect once the program
>> is correct.
>
> I don't know what "essentially same effect" is, but whatever formal
> definition of essential you took you would have to prove that two programs
> are equivalent according to the definition. That will require proving that
> the exception is not propagated or else handled to an "essentially" same
> result. Good luck with that.
>
Hello;
I did not check, but I assumed all along that the evaluation
of pre() can have no side effects?
i.e. in the process of executing
with pre ==> boolean valued expression
Then X could not be _modified_ during this check?
Because if X is modified, as a side effect of the check, from
say 3 to 5 then A(X):=1 will act differently if pre() was NOT
present.
Hence both code examples shown above will not be equivalent.
Therefore, I assume this can not happen, and it is guaranteed by
the language and compiler that pre() and post() do not have
side-effects?
Else this becomes like Heisenberg uncertainty principle.
thanks,
--Nasser
next prev parent reply other threads:[~2012-06-27 13:41 UTC|newest]
Thread overview: 125+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-06-20 13:39 about the new Ada 2012 pre/post conditions Nasser M. Abbasi
2012-06-20 14:02 ` Georg Bauhaus
2012-06-20 14:13 ` Dmitry A. Kazakov
2012-06-20 14:24 ` Nasser M. Abbasi
2012-06-20 14:37 ` Dmitry A. Kazakov
2012-06-20 17:02 ` Georg Bauhaus
2012-06-20 18:28 ` Dmitry A. Kazakov
2012-06-21 20:32 ` Randy Brukardt
2012-06-22 7:23 ` Dmitry A. Kazakov
2012-06-22 11:54 ` Georg Bauhaus
2012-06-22 12:39 ` Georg Bauhaus
2012-06-22 12:43 ` Dmitry A. Kazakov
2012-06-22 14:30 ` Georg Bauhaus
2012-06-22 14:36 ` Georg Bauhaus
2012-06-22 15:05 ` Dmitry A. Kazakov
2012-06-22 15:52 ` Georg Bauhaus
2012-06-22 16:35 ` Dmitry A. Kazakov
2012-06-22 16:53 ` Georg Bauhaus
2012-06-22 16:45 ` Georg Bauhaus
2012-06-22 17:24 ` Dmitry A. Kazakov
2012-06-22 19:41 ` Randy Brukardt
2012-06-22 23:08 ` Dmitry A. Kazakov
2012-06-23 10:46 ` Georg Bauhaus
2012-06-23 11:01 ` Dmitry A. Kazakov
2012-06-23 17:46 ` AdaMagica
2012-06-23 19:23 ` Dmitry A. Kazakov
2012-06-24 14:59 ` Georg Bauhaus
2012-06-24 16:06 ` Dmitry A. Kazakov
2012-06-24 19:51 ` Georg Bauhaus
2012-06-25 7:48 ` Dmitry A. Kazakov
2012-06-25 10:10 ` Georg Bauhaus
2012-06-25 8:08 ` Dmitry A. Kazakov
2012-06-25 10:17 ` Georg Bauhaus
2012-06-25 11:54 ` Dmitry A. Kazakov
2012-06-25 12:39 ` Georg Bauhaus
2012-06-25 12:51 ` Georg Bauhaus
2012-06-25 13:19 ` Dmitry A. Kazakov
2012-06-25 16:43 ` Georg Bauhaus
2012-06-25 14:08 ` stefan-lucks
2012-06-25 14:36 ` Dmitry A. Kazakov
2012-06-25 14:37 ` Dmitry A. Kazakov
2012-06-25 16:26 ` stefan-lucks
2012-06-25 19:42 ` Dmitry A. Kazakov
2012-06-26 11:50 ` stefan-lucks
2012-06-26 13:07 ` Dmitry A. Kazakov
2012-06-26 13:49 ` Georg Bauhaus
2012-06-26 14:45 ` Dmitry A. Kazakov
2012-06-26 16:48 ` Georg Bauhaus
2012-06-26 19:43 ` Dmitry A. Kazakov
2012-06-27 8:23 ` Georg Bauhaus
2012-06-27 8:52 ` Dmitry A. Kazakov
2012-06-27 10:30 ` Georg Bauhaus
2012-06-27 12:19 ` Dmitry A. Kazakov
2012-06-27 13:41 ` Nasser M. Abbasi [this message]
2012-06-28 7:00 ` Georg Bauhaus
2012-06-27 15:08 ` Georg Bauhaus
2012-06-29 21:03 ` Shark8
2012-06-30 8:26 ` Dmitry A. Kazakov
2012-06-30 12:54 ` Niklas Holsti
2012-07-05 2:58 ` Shark8
2012-07-05 7:24 ` Dmitry A. Kazakov
2012-07-06 6:23 ` Shark8
2012-07-06 7:57 ` Dmitry A. Kazakov
2012-07-07 1:09 ` Randy Brukardt
2012-07-07 8:44 ` Dmitry A. Kazakov
2012-06-26 14:54 ` stefan-lucks
2012-06-26 15:14 ` Dmitry A. Kazakov
2012-07-03 5:28 ` Randy Brukardt
2012-07-03 12:53 ` Dmitry A. Kazakov
2012-07-03 13:48 ` Georg Bauhaus
2012-07-03 14:06 ` Dmitry A. Kazakov
2012-07-03 16:12 ` Georg Bauhaus
2012-07-03 16:45 ` Georg Bauhaus
2012-07-05 1:45 ` Randy Brukardt
2012-07-05 7:48 ` Dmitry A. Kazakov
2012-07-05 19:11 ` Adam Beneschan
2012-07-05 19:55 ` Dmitry A. Kazakov
2012-07-06 7:41 ` Georg Bauhaus
2012-07-06 7:47 ` Georg Bauhaus
2012-07-06 8:05 ` Dmitry A. Kazakov
2012-07-06 8:30 ` Georg Bauhaus
2012-07-06 9:01 ` Dmitry A. Kazakov
2012-07-06 11:33 ` Simon Wright
2012-07-06 13:25 ` Dmitry A. Kazakov
2012-07-06 12:07 ` Georg Bauhaus
2012-07-06 13:37 ` Dmitry A. Kazakov
2012-07-06 16:17 ` Georg Bauhaus
2012-07-06 16:34 ` Georg Bauhaus
2012-07-06 19:18 ` Dmitry A. Kazakov
2012-07-07 1:24 ` Randy Brukardt
2012-07-07 9:09 ` Dmitry A. Kazakov
2012-07-07 1:18 ` Randy Brukardt
2012-07-07 9:14 ` Dmitry A. Kazakov
2012-07-07 12:06 ` Georg Bauhaus
2012-07-07 12:54 ` Dmitry A. Kazakov
2012-07-07 13:31 ` Georg Bauhaus
2012-07-03 5:10 ` Randy Brukardt
2012-07-03 4:51 ` Randy Brukardt
2012-07-03 12:46 ` Dmitry A. Kazakov
2012-07-05 2:18 ` Randy Brukardt
2012-07-05 8:48 ` Dmitry A. Kazakov
2012-07-05 12:07 ` Georg Bauhaus
2012-07-05 12:13 ` Georg Bauhaus
2012-07-05 12:31 ` Dmitry A. Kazakov
2012-07-05 18:16 ` Georg Bauhaus
2012-07-05 19:57 ` Dmitry A. Kazakov
2012-07-06 6:53 ` Georg Bauhaus
2012-07-07 0:43 ` Randy Brukardt
2012-07-07 8:06 ` Dmitry A. Kazakov
2012-07-07 11:17 ` Georg Bauhaus
2012-07-07 11:31 ` Dmitry A. Kazakov
2012-07-07 12:21 ` Georg Bauhaus
2012-07-07 13:03 ` Dmitry A. Kazakov
2012-06-20 19:18 ` Anh Vo
2012-06-20 20:16 ` Jeffrey R. Carter
2012-06-20 20:21 ` Jeffrey R. Carter
2012-06-20 20:51 ` Maciej Sobczak
2012-06-20 21:04 ` Dmitry A. Kazakov
2012-06-20 22:19 ` Robert A Duff
2012-06-21 6:32 ` Georg Bauhaus
2012-06-21 20:37 ` Randy Brukardt
2012-06-21 20:55 ` Jeffrey Carter
2012-06-22 19:15 ` Randy Brukardt
2012-06-21 20:23 ` Randy Brukardt
2012-06-22 7:34 ` Martin
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