From mboxrd@z Thu Jan  1 00:00:00 1970
X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me
X-Spam-Level: 
X-Spam-Status: No, score=-0.3 required=5.0 tests=BAYES_00,
	REPLYTO_WITHOUT_TO_CC autolearn=no autolearn_force=no version=3.4.4
X-Google-Thread: 103376,7d3cb5920e882220
X-Google-Attributes: gid103376,public,usenet
X-Google-Language: ENGLISH,ASCII-7-bit
Path: 
 g2news1.google.com!news3.google.com!news1.google.com!news.glorb.com!feed.xsnews.nl!border-1.ams.xsnews.nl!feeder1.cambrium.nl!feed.tweaknews.nl!193.141.40.65.MISMATCH!npeer.de.kpn-eurorings.net!npeer-ng1.kpn.DE!newsfeed.arcor.de!newsspool3.arcor-online.net!news.arcor.de.POSTED!not-for-mail
From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Subject: Re: Contracted exceptions for Ada
Newsgroups: comp.lang.ada
User-Agent: 40tude_Dialog/2.0.15.1
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
Reply-To: mailbox@dmitry-kazakov.de
Organization: cbb software GmbH
References: 
 <5947aa62-2547-4fbb-bc46-1111b4a0dcc9@x69g2000hsx.googlegroups.com>
 <KoSdnYQKWIUB9cXanZ2dnUVZ_oytnZ2d@comcast.com>
 <uvkiadiwrfh2.wi288ebeq18y.dlg@40tude.net> <fjd2t9$hkg$1@jacob-sparre.dk>
 <7m9wkymyi5h7.1235e72is9mp9.dlg@40tude.net>
 <1355376.ahPdGlRDJW@linux1.krischik.com>
 <1bvj0n3ana6zj.1b1q7na2q2i0a.dlg@40tude.net> <m23aubiufw.fsf@mac.com>
 <5tw4p3ydoalt$.eyhp82hd04ch.dlg@40tude.net> <m2prxeguv5.fsf@mac.com>
 <1vc7xfiouucfe.14549yzryw44i$.dlg@40tude.net> <m2d4tdgdmo.fsf@mac.com>
Date: Wed, 12 Dec 2007 11:20:32 +0100
Message-ID: <lvcjo9z26l0d.1jpr07ehyp2qn.dlg@40tude.net>
NNTP-Posting-Date: 12 Dec 2007 11:12:47 CET
NNTP-Posting-Host: 8a4d1e82.newsspool4.arcor-online.net
X-Trace: 
 DXC=PiQe405Rl2ieoCI^f\Y]Ea4IUK<Cl32<a4Fo<]lROoRa4nDHegD_]Re`JK\N<[l`CcDNcfSJ;bb[eFCTGGVUmh?dLK[5LiR>kgbMcmnhRn34<c
X-Complaints-To: usenet-abuse@arcor.de
Xref: g2news1.google.com comp.lang.ada:18906
Date: 2007-12-12T11:12:47+01:00
List-Id: <comp.lang.ada>

On Tue, 11 Dec 2007 20:50:07 +0000, Simon Wright wrote:

> "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> writes:
> 
>> On Mon, 10 Dec 2007 20:25:34 +0000, Simon Wright wrote:
>>
>>> The Ariane IV system engineers said to themselves, and probably in
>>> the design documentation, "The maximum horizontal velocity is
>>> X. Therefore the conversion to the fixed-point type _Whatever_
>>> cannot overflow. Therefore we do not need to handle exceptions for
>>> this conversion, so (given we are short of CPU power) we will not
>>> do any extra processing to avoid exceptions."
>>>
>>> Not sure they would have recognised "contract" in that context.
>>
>> Yes, my premise was that the type of H_Input changed from Ariane IV
>> to Ariane V. In this case translation of the conversion function
>> H_Input_To_Whatever could refute the second "therefore" because X
>> would not be the maximal possible value of H_Input anymore.
> 
> X was *never* the maximum possible value of H_Input!

In that case with contracted exceptions, the code without an exception
handler were illegal from the beginning.

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