From -1082731060880763948 X-Google-Thread: f78e5,174aa7b34b06a51 X-Google-Attributes: gidf78e5,public X-Google-Language: ENGLISH,ASCII-7-bit Path: g2news1.google.com!news4.google.com!news.glorb.com!news2.volia.net!newsfeed01.sul.t-online.de!t-online.de!newsfeed.vmunix.org!grolier!skynet.be!peer-uk.news.demon.net!kibo.news.demon.net!mutlu.news.demon.net!news.demon.co.uk!demon!stump.algebra.com!devnull From: SeeWebsiteForEmail@moderncppdesign.com ("Andrei Alexandrescu (See Website For Email)") Newsgroups: comp.std.c++ Subject: Re: Is this really unspecified behavior? Date: Wed, 21 Dec 2005 04:02:46 GMT Organization: Computer Science & Engineering, U of Washington, Seattle Lines: 30 Sender: mail2news@demon.net Approved: fjh@cs.mu.oz.au (Fergus Henderson , moderator of comp.std.c++) Message-ID: References: <1132759176.368850.264850@g43g2000cwa.googlegroups.com> <1132933832.802917.153350@g14g2000cwa.googlegroups.com> <1133551647.532929.325730@z14g2000cwz.googlegroups.com> <1133583412.951239.208510@g49g2000cwa.googlegroups.com> <1133910546.716987.80030@g14g2000cwa.googlegroups.com> <0l5ep1ppfhdj5p1pcu7e4na4ub0vjajlq3@4ax.com> <200512201341.jBKDfYuC056013@horus.isnic. NNTP-Posting-Host: news.news.demon.net Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Trace: news.demon.co.uk 1135137786 29339 158.152.254.254 (21 Dec 2005 04:03:06 GMT) X-Complaints-To: abuse@demon.net NNTP-Posting-Date: Wed, 21 Dec 2005 04:03:06 +0000 (UTC) X-Nntp-Posting-Host: parakeet.ee.washington.edu X-Robomod: STUMP, ichudov@algebra.com (Igor Chudov) X-User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.10) Gecko/20050716 Thunderbird/1.0.6 Mnenhy/0.7.2.0 X-Accept-Language: en-us, en X-Virus-Scanned: amavisd-new at cs.mu.OZ.AU X-Path: comp-std-cpp-robomod!not-for-mail X-Received: (from fjh@localhost) by mulga.cs.mu.OZ.AU (8.12.10+Sun/8.12.9/Submit) id jBL42ktH001383; Wed, 21 Dec 2005 15:02:46 +1100 (EST) X-Authentication-Warning: mulga.cs.mu.OZ.AU: fjh set sender to devnull@stump.algebra.com using -f X-Newsgroups: comp.std.c++ Xref: g2news1.google.com comp.std.c++:2867 Hyman Rosen wrote: > Andrew Koenig wrote: > >> Dijkstra claims that this indeterminacy in *language* definition is a >> good thing because it allows programmers to avoid overspecification in >> *program* definition. > > > Which is all fine and good if you believe that the programmer > has actually considered the possibility that more than one > guard is true. I suppose that's the case if you're proving > that your code is correct (and you don't make a mistake in > doing that), but lots of people don't do that in C++. I think > it's much more likely for two guards to be true because the > programmer has made an error rather than actually not caring > which branch is executed. One thing is that Dijkstra's suggested idiom didn't really catch on in real languages. The only one I know of is http://search.cpan.org/~trey/Commands-Guarded-0.01/Guarded.pm. Andrei --- [ comp.std.c++ is moderated. To submit articles, try just posting with ] [ your news-reader. If that fails, use mailto:std-c++@ncar.ucar.edu ] [ --- Please see the FAQ before posting. --- ] [ FAQ: http://www.jamesd.demon.co.uk/csc/faq.html ]