From 386468910636700868 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: f78e5,7eaa8faac8da5016 X-Google-Attributes: gidf78e5,public From: "Bill Wade" Subject: Re: Defect Report: member == in container iterators considered harmful Date: 1999/08/18 Message-ID: <7pcj1q$105@library1.airnews.net>#1/1 X-Deja-AN: 514091187 X-NNTP-Posting-Host: !X&ZP1k-X(+_/1- (Encoded at Airnews!) Approved: stephen.clamage@sun.com (comp.std.c++) References: <7p4nj8$n3u@enews4.newsguy.com> X-UID: 0000000001 X-Status: $$$T X-Mimeole: Produced By Microsoft MimeOLE V4.72.3110.3 Organization: Neosoft (using Airnews.net!) Abuse-Reports-To: abuse at airmail.net to report improper postings Newsgroups: comp.std.c++ Originator: clamage@taumet Darin Adler wrote in message <7p4nj8$n3u@enews4.newsguy.com>... >Proposed resolution: > >Add the following text to section 23.1 [lib.container.requirements]: > >The iterator and const_iterator types defined by a standard container may be >classes. If they are, any ==, !=, >, <, >=, or <= operator functions defined >for these classes to satisfy iterator requirements must be defined in the >std namespace, not as member functions. > >(Perhaps someone on the library committee can word it better. This is the >best I could do.) I'm not on the committee, but I believe the above is overly restrictive. Here are two ways that member functions can support the desired test ( i == ci; // iterator i; const_iterator ci). 1) bool iterator::operator==(const_iterator) const; 2) class iterator: public const_iterator { ... }; // inherit operator==() Also note that binary minus should be added to the list of operators. I believe that all iterators which support '<' also support '-'. [ 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 ]