From 3502682881747651317 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: f78e5,db4807a3f0a1e742 X-Google-Attributes: gidf78e5,public X-Google-ArrivalTime: 1994-08-07 15:12:33 PST Newsgroups: comp.std.c++ Path: bga.com!news.sprintlink.net!redstone.interpath.net!ddsw1!news.kei.com!sol.ctr.columbia.edu!howland.reston.ans.net!agate!msuinfo!harbinger.cc.monash.edu.au!news.cs.su.oz.au!metro!news From: maxtal@physics.su.OZ.AU (John Max Skaller) Subject: Re: Multiple inheritance and delete Message-ID: Sender: news@ucc.su.OZ.AU Nntp-Posting-Host: physics.su.oz.au Organization: School of Physics, University of Sydney, Australia References: <1994Aug02.045000.2253@corona.com> Date: Sun, 7 Aug 1994 20:47:17 GMT Lines: 39 In article <1994Aug02.045000.2253@corona.com> pkron@corona.com writes: >From: maxtal@physics.su.OZ.AU (John Max Skaller) > (would change default of member functions to "virtual" break > reams of code?...) >> Yes. In C++ there are two distinct kinds of class: >> >> a) polymorphic >> b) non-polymorphic >> >> and a whole lot of the language like RTTI works >> differently for polymorphic classes. >The language doesn't make any syntactic distinction--it's an >implementation issue based on the semantics of "virtual". The Working Paper explicitly defines a term "polymorphic type" and their semantics are distinct from non-polymorphic types. >The point here is whether non-polymorphic classes really add >anything to the language--my position being that they create more >potential for error than anything else. You would be right, were C++ not an extension of C, and were not efficiency one of the issues which makes C compatibility important. > >already broken that compatibility. To some extent, adding any >functions at all has broken it, since the member functions are not >accessible from C and the headers won't parse. That is true. Many people wish "struct" in C++ just meant exactly what it did in C. But it doesnt (and Bjarne says that decision was deliberate) -- JOHN (MAX) SKALLER, INTERNET:maxtal@suphys.physics.su.oz.au Maxtal Pty Ltd, 81A Glebe Point Rd, GLEBE Mem: SA IT/9/22,SC22/WG21 NSW 2037, AUSTRALIA Phone: 61-2-566-2189