From: Georg Bauhaus <rm.dash-bauhaus@futureapps.de>
Subject: Re: Integer overflow is int overflow (Re: Web browser in Ada)
Date: Tue, 27 Apr 2010 19:09:43 +0200
Date: 2010-04-27T19:09:44+02:00 [thread overview]
Message-ID: <4bd71a58$0$6889$9b4e6d93@newsspool2.arcor-online.net> (raw)
In-Reply-To: <1k01d6ghve2o7.15fw3tjmkbb7s.dlg@40tude.net>
On 27.04.10 18:13, Dmitry A. Kazakov wrote:
> On Tue, 27 Apr 2010 17:30:44 +0200, Georg Bauhaus wrote:
>
>> My conclusions would be that:
>>
>> Standard.Integer is a constrained subtype. Its objects are
>> not like (what is commonly known as) integers, a set that can
>> be extended at will.
>
> The set of integers is not extensible "at will." You probably meant that
> for any integer there exists at least one [actually an infinitely countable
> set] of greater or lesser integers. Nevertheless the set of integers (Z) is
> fixed.
Thanks for adding clarity. It is much needed.
> The value is determined by the expression and the
> language rules.
(OK, nitpicking, there is no value denoted by a named number
if determination does not actually happen. Words mean
nothing unless they are given meaning. ;-) ;-)
>> they are not objects, and they can hit compiler capacity limits.
>
> Whether they are [run-time] objects is up to compiler. The compiler in Ada
> has certain freedom to "objectize" and "deobjectize" things.
Thanks, I didn't know this.
> You need overflow in order to define the behavior of the operations closed
> only in Z. E.g. "+".
True if it is not possible to define "+" in terms of saturation
or wrap-around, I think. Correct?
However, programmers do not define "+" in their C programs.
They use "+"!
Then overflow occurs, and not to prove the soundness of the
language definition, but as a mishap.
next prev parent reply other threads:[~2010-04-27 17:09 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-04-23 8:03 Web browser in Ada Gautier write-only
2010-04-23 13:56 ` Maciej Sobczak
2010-04-23 14:37 ` Georg Bauhaus
2010-04-27 11:41 ` Martin Krischik
2010-04-27 12:22 ` Georg Bauhaus
2010-04-27 14:00 ` AdaMagica
2010-04-27 15:30 ` Integer overflow is int overflow (Re: Web browser in Ada) Georg Bauhaus
2010-04-27 16:13 ` Dmitry A. Kazakov
2010-04-27 17:09 ` Georg Bauhaus [this message]
2010-04-27 17:56 ` Dmitry A. Kazakov
2010-04-23 21:33 ` Web browser in Ada Gautier write-only
2010-04-24 0:38 ` Peter C. Chapin
2010-04-25 5:38 ` Gautier write-only
2010-04-25 16:24 ` Peter C. Chapin
2010-04-25 10:41 ` Georg Bauhaus
2010-04-25 16:29 ` Peter C. Chapin
2010-04-26 15:37 ` Warren
2010-04-24 9:51 ` leonid
2010-04-25 5:04 ` Gautier write-only
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