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=-1.1 required=5.0 tests=BAYES_00, PP_MIME_FAKE_ASCII_TEXT autolearn=no autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII X-Google-Thread: 103376,ab66185f2bca0483 X-Google-Attributes: gid103376,public X-Google-ArrivalTime: 2002-11-15 05:30:03 PST Path: archiver1.google.com!news1.google.com!newsfeed.stanford.edu!canoe.uoregon.edu!arclight.uoregon.edu!newsfeed.mathworks.com!oleane.net!oleane!nnrp.oleane.net!not-for-mail From: "Jean-Pierre Rosen" Newsgroups: comp.lang.ada Subject: Re: Extension of non-limited type needs limited component Date: Fri, 15 Nov 2002 14:29:31 +0100 Organization: Guest of France Telecom Oleane's newsreading service Message-ID: References: NNTP-Posting-Host: mailhost.axlog.fr X-Trace: s1.read.news.oleane.net 1037366813 26217 195.25.228.57 (15 Nov 2002 13:26:53 GMT) X-Complaints-To: abuse@oleane.net NNTP-Posting-Date: Fri, 15 Nov 2002 13:26:53 +0000 (UTC) X-Priority: 3 X-MSMail-Priority: Normal X-Newsreader: Microsoft Outlook Express 5.50.4807.1700 X-MimeOLE: Produced By Microsoft MimeOLE V5.50.4807.1700 Xref: archiver1.google.com comp.lang.ada:30939 Date: 2002-11-15T14:29:31+01:00 List-Id: "Dmitry A. Kazakov" a �crit dans le message news: > Both Ada and SmallTalk [AFAIK] do not crash when such thing happens. > But this is not the problem. The problem is that though one could wish > to detect all such and similar cases at compile time, one cannot. This > does not mean that we should drop compile-time checks. [To put it > clear, Ada is right, SmallTalk is wrong! (:-))] It only means that the > argument, "this is not allowed, because it cannot be fully checked at > compile time" is wrong. Alas, there are many damn useful things > uncheckable at compile time. ... with tagged types. The benefit, and drawback, of tagged types is that they allow dynamic typing, therefore requiring (isn't it surprising) dynamic checking. More flexibility, less security. If you want full compile-time checking, don't use tagged types. At least in Ada, you have a choice! -- --------------------------------------------------------- J-P. Rosen (rosen@adalog.fr) Visit Adalog's web site at http://www.adalog.fr