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: 103376,585fd78267abd80c
X-Google-Attributes: gid103376,domainid0,public,usenet
X-Google-Language: ENGLISH,ASCII-7-bit
Path: 
 g2news2.google.com!news3.google.com!feeder.news-service.com!newsfeed00.sul.t-online.de!t-online.de!storethat.news.telefonica.de!telefonica.de!newsfeed.arcor.de!newsspool1.arcor-online.net!news.arcor.de.POSTED!not-for-mail
From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Subject: Re: On pragma Precondition etc.
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: <4889886d$0$18827$9b4e6d93@newsspool2.arcor-online.net>
 <Pine.LNX.4.64.0807251224010.10913@medsec1.medien.uni-weimar.de>
 <f9112d8f-1c5a-4533-88ed-b4c22d108ac8@q5g2000prf.googlegroups.com>
 <6etsi6F8mbmbU2@mid.individual.net> <488efc8d$1@news.post.ch>
 <py8uf7h03ctg$.qp3cvq1pos4a$.dlg@40tude.net>
 <488f26e8$0$20705$9b4e6d93@newsspool4.arcor-online.net>
 <1668bcqbkwlun$.mzzrx5m5ug2t$.dlg@40tude.net>
 <488f3d67$0$20703$9b4e6d93@newsspool4.arcor-online.net>
 <13nqxvysv2w75.bpxxsup39g9u$.dlg@40tude.net>
 <48902f08$0$1064$9b4e6d93@newsspool3.arcor-online.net>
Date: Wed, 30 Jul 2008 15:47:30 +0200
Message-ID: <1lt840f6z5lva.8rilgn0ds47u$.dlg@40tude.net>
NNTP-Posting-Date: 30 Jul 2008 15:47:30 CEST
NNTP-Posting-Host: 07e33552.newsspool4.arcor-online.net
X-Trace: 
 DXC=50U>R0[BX[RU6b:FjPaGjQ4IUK<Cl32<Q4Fo<]lROoRQFl8W>\BH3YRNHnmVf8:^][DNcfSJ;bb[UFCTGGVUmh?TLK[5LiR>kgRikoKXoK<bMY
X-Complaints-To: usenet-abuse@arcor.de
Xref: g2news2.google.com comp.lang.ada:7111
Date: 2008-07-30T15:47:30+02:00
List-Id: <comp.lang.ada>

On Wed, 30 Jul 2008 11:06:16 +0200, Georg Bauhaus wrote:

> Dmitry A. Kazakov schrieb:
>> On Tue, 29 Jul 2008 17:55:18 +0200, Georg Bauhaus wrote:
> 
>>> What if one precondition states a relation between two suprogram
>>> parameters, or between properties of two suprogram parameters?
>> 
>> This case is equivalent to full multiple dispatch. Ada does not have it. If
>> it had multiple dispatch then it would clearer how to deal with the
>> corresponding contracts (=conditions).
> 
> How about this: For the purpose of expressing the contract
> of a subprogram, dream up its "contract-type".

This type is obviously a tuple of the parameters of Foo.

> Base this type on
> 
> (1) the precursor's contract-type (up the derivation hierarchy)
> (2) the profile
> 
> So given
> 
>     function Foo(X, Y: Integer) return Whatever;
> 
> denote the precondition of its "contract-type" by something like
> 
>     Foo'Precondition;

Naming does not solve the problem.

In presence of:

   subtype My_Integer is Integer range 1..500;
   type My_Whatever is new Whatever with private;

what are the preconditions of Foo defined on the tuples:

Integer x My_Integer x Whatever
My_Integer x Integer x Whatever
Integer x My_Integer x Whatever
My_Integer x My_Integer x Whatever
Integer x My_Integer x My_Whatever
My_Integer x Integer x My_Whatever
Integer x My_Integer x My_Whatever
My_Integer x My_Integer x My_Whatever

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