From -4907756887138551802 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: f78e5,5056bc953972b4f6 X-Google-Attributes: gidf78e5,public X-Google-ArrivalTime: 2002-11-27 08:48:32 PST Path: archiver1.google.com!news1.google.com!newsfeed.stanford.edu!news-spur1.maxwell.syr.edu!news.maxwell.syr.edu!newsfeed.icl.net!newsfeed.fjserv.net!kibo.news.demon.net!mutlu.news.demon.net!demon!mail2news.demon.co.uk!devnull From: anthony.williamsNOSPAM@anthonyw.cjb.net (Anthony Williams) Newsgroups: comp.std.c++ Subject: Re: Rationale for 7.1.2/6 Date: Wed, 27 Nov 2002 16:48:30 +0000 (UTC) Organization: Customer of PlusNet Lines: 47 Approved: fjh@cs.mu.oz.au (Fergus Henderson , moderator of comp.std.c++) Message-ID: References: <2ONE9.4412$sW.228339932@newssvr13.news.prodigy.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: mail2news.demon.co.uk 1038415710 24147 10.0.0.1 (27 Nov 2002 16:48:30 GMT) X-Complaints-To: abuse@demon.net NNTP-Posting-Date: Wed, 27 Nov 2002 16:48:30 +0000 (UTC) X-Received: from mulga.cs.mu.oz.au ([128.250.1.22]) by news.demon.co.uk with esmtp (Exim 4.05) id 18H5MS-0006HK-00 for mail2news@news.news.demon.net; Wed, 27 Nov 2002 16:48:28 +0000 X-Received: from localhost (localhost [[UNIX: localhost]]) by mulga.cs.mu.OZ.AU id DAA06928; Thu, 28 Nov 2002 03:48:24 +1100 (EST) X-Authentication-Warning: mulga.cs.mu.OZ.AU: fjh set sender to devnull@stump.algebra.com using -f X-Path: comp-std-cpp-robomod!not-for-mail X-Robomod: STUMP, ichudov@algebra.com (Igor Chudov) X-Delivered-To: std-c++@ncar.ucar.edu X-Newsgroups: comp.std.c++ X-Face: w~ml[K\+Z~(W,eDy5FNdP0]LBZRC}ek=-6H?eqAJ+tIz$#3Pl)L!'MGq!/|=MjW_f.'gL)=;-'HTa/zlF\rn$l>9Dx) writes: > In article <2ONE9.4412$sW.228339932@newssvr13.news.prodigy.com>, > on Tue, 26 Nov 2002 17:11:55 +0000 (UTC), > cpdaniel@mvps.org ("Carl Daniel") wrote: > > > 7.1.2/6 says > > > > "The explicit specifier shall be used only in declarations of constructors > > within a class declaration; see > > 12.3.1." > > > > Why? In particular, it seems to me that it'd be useful to be able to apply > > 'explicit' to conversion operators (e.g. operator int()). > > I'd have said that if you don't want implicit conversions to take > place, you probably shouldn't write conversion operators. If you want > explicit conversion operators, give them names like (e.g.) "as_int()" > and call them explicitly. > > > Is there some reason that explicit was so severely limited by definition? > > I don't think you can reasonably claim that it's "severely limited" - > it does exactly what it was intended to do. Of course, if your > argument is persuasive enough, you may be able to encourage the > commitee to embrace your suggestion in the next standard... There was a long discussion either here or on comp.lang.c++.moderated about this, recently. Basically, it comes down to this: if you're writing generic code, how do you know how to spell "as_int()" without requiring the user of the class to specialize a traits template? Bear in mind that this traits template will end up being called different things for every different library that uses it, and also different libraries will require "as_double()", "as_string()" and "as_foo()". Anthony -- Anthony Williams Senior Software Engineer, Beran Instruments Ltd. Remove NOSPAM when replying, for timely response. --- [ 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 ]