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=-1.9 required=5.0 tests=BAYES_00 autolearn=ham
	autolearn_force=no version=3.4.4
X-Google-Thread: a07f3367d7,e55245590c829bef
X-Google-Attributes: gida07f3367d7,public,usenet
X-Google-NewGroupId: yes
X-Google-Language: ENGLISH,ASCII-7-bit
Path: 
 g2news1.google.com!news1.google.com!news3.google.com!feeder.news-service.com!85.214.198.2.MISMATCH!eternal-september.org!feeder.eternal-september.org!.POSTED!not-for-mail
From: Simon Wright <simon@pushface.org>
Newsgroups: comp.lang.ada
Subject: Re: _Type vs no _Type
Date: Sat, 06 Nov 2010 13:34:41 +0000
Organization: A noiseless patient Spider
Message-ID: <m2aalmziby.fsf@pushface.org>
References: <86wroy58ff.fsf@gareth.avalon.lan>
	<iale5p$2f6$1@tornado.tornevall.net>
	<86pqup5xfy.fsf@gareth.avalon.lan>
	<becbd7a4-89e6-4d81-b7d8-7d18ac75c1f9@j2g2000yqf.googlegroups.com>
	<86y69d3rec.fsf@gareth.avalon.lan>
	<ian4b2$p9h$1@tornado.tornevall.net> <82lj5c5ecm.fsf@stephe-leake.org>
	<iapnmm$p5j$1@tornado.tornevall.net> <op.vlj5fgv0ule2fv@garhos>
	<m24obz1nkj.fsf@pushface.org> <82zktq4n9b.fsf_-_@stephe-leake.org>
	<iaurli$fml$1@tornado.tornevall.net>
	<wcczktnbsk7.fsf@shell01.TheWorld.com>
	<ib1llq$8mp$1@tornado.tornevall.net>
	<wccfwvf5qp8.fsf@shell01.TheWorld.com>
	<ib2872$pb7$1@tornado.tornevall.net>
	<g99f7vycatem$.1xtq9qp9kz0rt.dlg@40tude.net>
	<4cd53555$0$7665$9b4e6d93@newsspool1.arcor-online.net>
	<1hjbm9sq2q6v6.1o1jb481odeuh$.dlg@40tude.net>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Injection-Info: mx01.eternal-september.org;
 posting-host="dFCm8HWntFqmDIilBLqEJQ";
	logging-data="12294"; mail-complaints-to="abuse@eternal-september.org";
	posting-account="U2FsdGVkX19YuU61WvJ0N4CkHoakwhaoEvSPOGmGL04="
User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.2 (darwin)
Cancel-Lock: sha1:XBw2bgZGx6Y6WvtfFdA6LeOzlTw=
	sha1:j5VoHSZlx+hCzHjKJfTvpozGbmM=
Xref: g2news1.google.com comp.lang.ada:15329
Date: 2010-11-06T13:34:41+00:00
List-Id: <comp.lang.ada>

"Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> writes:

> On Sat, 06 Nov 2010 12:00:38 +0100, Georg Bauhaus wrote:
>
>> On 11/6/10 8:12 AM, Dmitry A. Kazakov wrote:
>> 
>>> Hmm, I would expect you arguing for
>>>
>>>     function "/" (Dividend : T; Divisor : T) return T;
>>>
>>> For commutative operations like "+" it becomes a bit difficult:
>> 
>> You aren't suggesting the computer-"+" is a commutative
>> operation, are you?
>
> I do. The implementation of "+" is not "strictly" commutative, but its
> interface does not tell that. The implied, not stated contract, is
> that "+" is indeed commutative allowing certain compiler
> optimizations. A numeric expression denotes a set of results
> satisfying certain conditions (accuracy constraints required by the
> ARM). Within these limits "+" is "weakly" commutative.

One would very much _hope_ that these two would behave commutatively, of
course.

function "+" (L : Time; R : Duration) return Time;
function "+" (L : Duration; R : Time) return Time;