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: 103376,1a52c822fc0dbb23 X-Google-Attributes: gid103376,public X-Google-Language: ENGLISH,ASCII-7-bit Path: g2news1.google.com!news1.google.com!news2.google.com!news.glorb.com!news.mv.net!nntp.TheWorld.com!not-for-mail From: Robert A Duff Newsgroups: comp.lang.ada Subject: Re: Rational for not making cursor tagged in Containers Date: Fri, 20 Apr 2007 16:44:11 -0400 Organization: The World Public Access UNIX, Brookline, MA Message-ID: References: <1176998738.656903.141250@q75g2000hsh.googlegroups.com> <1177010938.200523.325290@p77g2000hsh.googlegroups.com> <1a8y2vakorfhx.225uqh4hifpd$.dlg@40tude.net> <1xmzi7newnilp.23m3zze8h9yi.dlg@40tude.net> <1177066583.5876.30.camel@localhost.localdomain> <1177080147.5876.87.camel@localhost.localdomain> <1q1kx2jlcvnuj.ck0711mj4few$.dlg@40tude.net> <1177097829.26685.36.camel@localhost.localdomain> NNTP-Posting-Host: shell01.theworld.com Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: pcls6.std.com 1177101852 26081 192.74.137.71 (20 Apr 2007 20:44:12 GMT) X-Complaints-To: abuse@TheWorld.com NNTP-Posting-Date: Fri, 20 Apr 2007 20:44:12 +0000 (UTC) User-Agent: Gnus/5.1008 (Gnus v5.10.8) Emacs/21.3 (irix) Cancel-Lock: sha1:TP75qDscVPBAmuubjBtgQxcJYzs= Xref: g2news1.google.com comp.lang.ada:15175 Date: 2007-04-20T16:44:11-04:00 List-Id: Georg Bauhaus writes: > On Fri, 2007-04-20 at 17:13 +0200, Dmitry A. Kazakov wrote: >> Also I fail to understand why polymorphic objects has to be records >> and not arrays or access types. Why array or number cannot have >> discriminants, but records can? > > "Uniformity. Discriminants make sense for any composite type. In Ada > 9X, we allow them for any composite type except array types. The > array-type restriction is for ease of implementation -- it does not > simplify the language nor make it easier to use. Hmm... That sounds like something I would write. >...Adding another > restriction for task types would decrease uniformity further. > Discriminants are allowed for protected types; disallowing them for > tasks would make tasks a second-class citizen." > -- http://archive.adaic.com/standards/95lsn/LSN1044.TaskDisc.txt .... OK, I looked it up, and indeed someone named Bob Duff wrote it. That's me! ;-) Thanks for the link. In this Language Study Note (LSN), I was arguing that task types should be allowed to have discriminants. (And indeed they can in Ada 95 and in Ada.) I also thought (and continue to think) that array types should be allowed to have discriminants. The quote above was a jab at people who thought otherwise. I lost that argument. - Bob