From 1961622106285535319 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: f78e5,7eaa8faac8da5016 X-Google-Attributes: gidf78e5,public From: Valentin Bonnard Subject: Re: Defect Report: member == in container iterators considered harmful Date: 1999/08/23 Message-ID: <37BD41BF.1447@wanadoo.fr>#1/1 X-Deja-AN: 516097118 Content-Transfer-Encoding: 7bit Approved: Fergus Henderson References: <7p4nj8$n3u@enews4.newsguy.com> <37B95B96.7F37@wanadoo.fr> <7pcoa8$2kf0@enews2.newsguy.com> <37BABF02.3EBE@wanadoo.fr> <7pf1b2$ls8@enews3.newsguy.com> <37BC0B5B.4AD8@wanadoo.fr> <7pi5ui$314r@enews3.newsguy.com> X-Original-Date: Fri, 20 Aug 1999 13:53:35 +0200 Content-Type: text/plain; charset=us-ascii X-Complaints-To: news@news.unimelb.edu.au X-Trace: izvestia.its.unimelb.edu.au 935399830 26211 128.250.29.17 (23 Aug 1999 09:17:10 GMT) Organization: Ecole normale superieure X-Auth: PGPMoose V1.1 PGP comp.std.c++ iQBFAgUAN8ERduEDnX0m9pzZAQGFXAF9EbxAXm7siFl2z18MSpJf46Vrtjw4AoNm t9pe6/TGPBh/EN+zmI7oMrUuEpfSer9M =GEPo Mime-Version: 1.0 NNTP-Posting-Date: 23 Aug 1999 09:17:10 GMT Newsgroups: comp.std.c++ Darin Adler wrote: > > > Darin Adler wrote: > >> I meant to propose a non-member function, which can be a friend if > >> necessary. As I understand it, the friend function above *is* a non-member > >> function. > > Valentin Bonnard wrote: > > Not really. It isn't a member, it isn't a normal global > > function, it's something completely magical, a friend. > > Before your messages in this thread, I had understood that "friend" was a > relationship between a class and a function, rather than a special category > of function. Actually, it's both. > But you're saying here that a friend function is a special kind > of function, not a non-member function which has been granted special > privileges. Again, it's both a non-member function with privileges and a special kind of function. > I thought that a non-member function that was not a friend would work. But > it now seems that a friend is required. Correct > It still seems to me that someone could make const_iterator be a non-nested > class with a library-hidden name and just have the typedef inside the class. Yes, why not. > On the other hand, if only a friend function works, it still seems that my > DR was correct. Hum, hum [quotation: > However, the following code is not > guaranteed to work: > > bool check_equal(std::deque::iterator i, > std::deque::const_iterator ci) > { > return i == ci; > } > > The reason for this is that there's no requirement that the == operator be > defined as a non-member function. --end quotation] > Here's what I'd like to know: > > Do you still think the DR solution I proposed is incorrect? As you seem to imply in your DR that a non friend function solves the problem, yes. If all you wanted to say in your DR was that there is problem which should be solved the Right Way, then I have no objection against that. > If the standard is amended to require a non-member function, but the > only kind of non-member function that will work is a friend, doesn't that > mean that all implementers will have to use friend functions? Does the > standard have to explicitly mention "friend" to be correct? No, it doesn't has to do that. The standard doesn't even have to mention the notion of membership of overloaded operators. > Would a simple wording change make my DR solution correct, corresponding > to the experiment I did on my copy of the library? Remove all the references to membership ? > Will you help me correct the DR and resubmit it? Yes > I don't care so much if I made a mistake -- I'm willing to admit it if I > did. But I do care whether the DR is wrong or right. I'd like the DR to have > a good chance for fair consideration, unless there's a flaw in it. I am sure it will get fair consideration. > I believe your original comment, saying that my suggested solution won't > work, was passed on to the committee. Correct > I think this will unnecessarily reduce > the chance of the defect report being accepted. It will reduce the chance of the DR being accepted in an incorrect/misleading form. It won't kill the DR. -- Valentin Bonnard --- [ 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://reality.sgi.com/austern_mti/std-c++/faq.html ]