From -6164833261265457145 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: f78e5,18c6d861cef54158 X-Google-Attributes: gidf78e5,public X-Google-ArrivalTime: 2003-01-02 11:17:04 PST Path: archiver1.google.com!news1.google.com!newsfeed.stanford.edu!newsmi-us.news.garr.it!NewsITBone-GARR!news.mailgate.org!newsfeed.icl.net!newsfeed.fjserv.net!colt.net!kibo.news.demon.net!mutlu.news.demon.net!demon!mail2news.demon.co.uk!devnull From: abarbati@iaanus.com (Alberto Barbati) Newsgroups: comp.std.c++ Subject: Re: automatic downcast support through function parameters Date: Thu, 2 Jan 2003 19:17:00 +0000 (UTC) Organization: Newsfeeds.com http://www.newsfeeds.com 80,000+ UNCENSORED Newsgroups. Lines: 56 Approved: fjh@cs.mu.oz.au (Fergus Henderson , moderator of comp.std.c++) Message-ID: <3e14211b$1_4@corp.newsgroups.com> References: <23478c42.0212310830.23dbc580@posting.google.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit X-Trace: mail2news.demon.co.uk 1041535020 16215 10.0.0.1 (2 Jan 2003 19:17:00 GMT) X-Complaints-To: abuse@demon.net NNTP-Posting-Date: Thu, 2 Jan 2003 19:17:00 +0000 (UTC) X-Received: from mulga.cs.mu.oz.au ([128.250.1.22]) by news.demon.co.uk with esmtp (Exim 4.05) id 18UApu-0004DO-00 for mail2news@news.news.demon.net; Thu, 02 Jan 2003 19:16:59 +0000 X-Received: by mulga.cs.mu.OZ.AU id GAA04086; Fri, 3 Jan 2003 06:16:47 +1100 (EST) X-Authentication-Warning: mulga.cs.mu.OZ.AU: fjh set sender to devnull@stump.algebra.com using -f X-Path: comp-std-cpp-robomod!not-for-mail X-Robomod: STUMP, ichudov@algebra.com (Igor Chudov) X-Delivered-To: std-c++@ncar.ucar.edu X-User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.0; it-IT; rv:1.2.1) Gecko/20021130 X-Accept-Language: en-us, en, it X-Newsgroups: comp.std.c++ X-Comments: This message was posted through Newsfeeds.com X-Comments2: IMPORTANT: Newsfeeds.com does not condone, nor support, spam or any illegal or copyrighted postings. X-Comments3: IMPORTANT: Under NO circumstances will postings containing illegal or copyrighted material through this service be tolerated!! X-Report: Please report illegal or inappropriate use to X-Abuse-Info: Please be sure to forward a copy of ALL headers, INCLUDING the body (DO NOT SEND ATTACHMENTS) X-OriginalArrivalTime: 02 Jan 2003 11:23:36.0375 (UTC) FILETIME=[643F2470:01C2B251] X-Spam-Status: No, hits=-7.3 required=5.0 tests=INVALID_MSGID,IN_REP_TO,NOSPAM_INC,REFERENCES, SPAM_PHRASE_01_02,USER_AGENT,USER_AGENT_MOZILLA_UA, X_ACCEPT_LANG version=2.41 Xref: archiver1.google.com comp.std.c++:16642 danielgutson@hotmail.com wrote: > What you think? What's the point in defining f taking a Base* if I mean Derived*? (or at least I mean Derived* for overloading resolution). In other words: why should I choose this syntax instead of declaring f taking a Derived*? What about Base having more than one derived class? For example if struct Base{}; struct Der1 : Base{}; struct Der2 : Base{}; void g(Base* b); void g(Der1* d); void g(Der2* d); void f(upcasted Base* b) { g(b); // which g? } What if one or more derived classes are incomplete at the point of declaration of f? For example: struct Base{}; struct Der; void g(Base* b); void g(Der* d); void f(upcasted Base* b) { g(b); // which g? } struct Der : Base{}; If I have to give one frank opinion, I would say that this syntax is both useless, error-prone and difficult for a compiler to implement correctly. Maybe I'm not understanding it correctly... Alberto -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 80,000 Newsgroups - 16 Different Servers! =----- --- [ 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 ]