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: 103376,635cd9622b25ae59
X-Google-Attributes: gid103376,public
X-Google-Language: ENGLISH,ASCII-7-bit
Path: 
 g2news2.google.com!news3.google.com!news4.google.com!newsfeed.stanford.edu!news.tele.dk!news.tele.dk!small.news.tele.dk!newsfeed.cw.net!cw.net!news-FFM2.ecrc.de!noris.net!newsfeed.arcor.de!news.arcor.de!not-for-mail
Date: Thu, 27 Apr 2006 17:39:39 +0200
From: Georg Bauhaus <bauhaus@futureapps.de>
User-Agent: Thunderbird 1.5.0.2 (Windows/20060308)
MIME-Version: 1.0
Newsgroups: comp.lang.ada
Subject: Re: Type safety, C++ and code generation
References: <e2q6p8$idj$1@sunnews.cern.ch>
   <1146143954.169807.207080@t31g2000cwb.googlegroups.com>
   <e2qj9l$edt$1@sunnews.cern.ch>
 <1146148380.102042.119860@y43g2000cwc.googlegroups.com>
 <e2qn8t$n13$1@sunnews.cern.ch>
In-Reply-To: <e2qn8t$n13$1@sunnews.cern.ch>
X-Enigmail-Version: 0.94.0.0
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit
Message-ID: <445101bf$0$11061$9b4e6d93@newsread4.arcor-online.net>
Organization: Arcor
NNTP-Posting-Date: 27 Apr 2006 19:39:11 MEST
NNTP-Posting-Host: f6ddbe12.newsread4.arcor-online.net
X-Trace: 
 DXC=fHNg?`DRaYka1IKbSTkC[i:ejgIfPPlddjW\KbG]kaMh]kI_X=5Keaf\m@?J;XLOUlhP3YJKgE\jlDVfi7HR?MomTaST0T@UMJo
X-Complaints-To: usenet-abuse@arcor.de
Xref: g2news2.google.com comp.lang.ada:3966
Date: 2006-04-27T19:39:11+02:00
List-Id: <comp.lang.ada>

Maciej Sobczak wrote:

> type ranged_type<int, 0, 250> Speed;
> Speed s1, s2, s3; // with some values
> s1 = s2 + s3; // OK
> s1 = s2 * s3; // not OK
> 
> The addition is fine, but the multiplication should not be provided,
> because speed multiplied by speed is not a speed. Can you extend your
> class so that the compiler will refuse to compile the second operation
> above?
> (Ada, anyone? :) )

Just so it is visible:


procedure useop is

   s1, s2, s3: SPEED;  -- with some values

begin
   s3 := s1 * s2;
end useop;

     8.    s3 := s1 * s2;
                    |
        >>> cannot call abstract subprogram "*"

where

package Op is

   type SPEED is range 0 .. 250;

   function "*"(a, b: SPEED) return SPEED is abstract;

end Op;