220 8390 article Path: news.gmane.org!not-for-mail From: Dietmar Kuhl Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Proposal: Default swap operation Date: Wed, 1 Jan 2014 03:17:01 +0100 Lines: 60 Approved: news@gmane.org Message-ID: References: Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 (Mac OS X Mail 7.1 \(1827\)) Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable X-Trace: ger.gmane.org 1388796149 3787 80.91.229.3 (4 Jan 2014 00:42:29 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Sat, 4 Jan 2014 00:42:29 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBAABB6VRTWLAKGQEIWONTWI@isocpp.org Sat Jan 04 01:42:35 2014 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-lb0-f197.google.com ([209.85.217.197]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1VzFJz-000106-9w for gclcip-std-proposals@m.gmane.org; Sat, 04 Jan 2014 01:42:35 +0100 Original-Received: by mail-lb0-f197.google.com with SMTP id u14sf26126703lbd.0 for ; Fri, 03 Jan 2014 16:42:35 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:subject:from:in-reply-to:date :message-id:references:to:x-original-sender :x-original-authentication-results:reply-to:precedence:mailing-list :list-id:list-post:list-help:list-archive:list-subscribe :list-unsubscribe:content-type:content-transfer-encoding; bh=cGCzbcTg/Q8r/1BcFuPI9d3oQQilEEaedii6jQNKnLU=; b=B98m+afeFgR5osGBRyDeNe8Rt9W1pajBjfPZ6NCA4F+MBiYmOoPLBvGH19/NCUAt0D rEsia2Ckq7JrN7ALIB2cKq6UBtKvJ4PCEPrzVkkg9kUkcWwxl3zk3rzVTZjE0GKk3Ge0 wgcuxcFpJ2v7ckiZXvL92R8OSUSDtgSMCM5KDI9u2HADFMIkUcBjHp3EHu53s5vU2gDh QxGOM8Rd1y92iVW4ran4eNv4ZU1XNklTov4lx4lwC4YeZ9QfU08bWjIZA2ejm44V3V7K kpMCAHPQydMoZNOOUxoSK8H66J5JU8dFj8Gt3dfecKpseZr0DvMZi8rpPdxTz9NIZ0uC s98g== X-Gm-Message-State: ALoCoQmqV47b5yur5dWINBVuw8EmHnoT6I8XU/0RhwXwTolDQxry8mbZPwTykyMTZaH8a7mscxQ+ X-Received: by 10.180.91.130 with SMTP id ce2mr88114wib.7.1388796154845; Fri, 03 Jan 2014 16:42:34 -0800 (PST) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.180.89.41 with SMTP id bl9ls146434wib.9.gmail; Fri, 03 Jan 2014 16:42:34 -0800 (PST) X-Received: by 10.180.126.2 with SMTP id mu2mr2352494wib.4.1388796154135; Fri, 03 Jan 2014 16:42:34 -0800 (PST) Original-Received: by 10.194.216.231 with SMTP id ot7mswjc; Tue, 31 Dec 2013 18:17:02 -0800 (PST) X-Received: by 10.180.75.115 with SMTP id b19mr50142795wiw.19.1388542622725; Tue, 31 Dec 2013 18:17:02 -0800 (PST) Original-Received: from nm16.bullet.mail.ir2.yahoo.com (nm16.bullet.mail.ir2.yahoo.com. [212.82.96.39]) by mx.google.com with SMTP id df6si19266872wjc.144.2013.12.31.18.17.02 for ; Tue, 31 Dec 2013 18:17:02 -0800 (PST) Received-SPF: softfail (google.com: domain of transitioning dietmar.kuehl@me.com does not designate 212.82.96.39 as permitted sender) client-ip=212.82.96.39; Original-Received: from [212.82.98.61] by nm16.bullet.mail.ir2.yahoo.com with NNFMP; 01 Jan 2014 02:17:02 -0000 Original-Received: from [46.228.39.104] by tm14.bullet.mail.ir2.yahoo.com with NNFMP; 01 Jan 2014 02:17:02 -0000 Original-Received: from [127.0.0.1] by smtp141.mail.ir2.yahoo.com with NNFMP; 01 Jan 2014 02:17:02 -0000 X-Yahoo-Newman-Id: 429976.8235.bm@smtp141.mail.ir2.yahoo.com X-Yahoo-Newman-Property: ymail-3 X-YMail-OSG: Y0EYXZ0VM1mMdGLhf4K4HziuegspQyhOPZDWG73Gu.8EpPK Df_AGZ5YvZAMt1LH5pb2USLjdzBSvmh0QO7l1LSu5_WE874fkGFJxh2Lp0ra C1txYoEF.OMwpAJqRa9bpwSQz.Ldk0PJHYOxSnej2VliHZidSc156tCuyfpo saabeOGy_wKoER9JMYm3sulgWaz..AtF8B7_.77vwLHb.veFEvVFDR6cqzCm Ryr6OSHxBgXqU_0r4VzGw2ilBvmNlTu_A8PnP9nZS5hiopr74FADTNQ1u_Dz 9BrN4ipX1n5ZfhfA5kHHp6WNAQ8dQLpq3ePrjv8YSz5i87i3xHcyIFReZfxn ZGFIhQUgZ8lbC6O5gBZNkKE1V11.9oZVFCFXEW53tgXPnfk_kTyTvXBWaqpq IQbP14MiIfo0c2UKL_V_c.7MHm5bUCdArMRTVJHJ9HuFt7jOL7so51pFuf9t tW2.SSMZvcE5jNIxidmbp_6SSNAbWxbm1_eJrbnsr1tpMDvCWhFlcxHGnGfb tNjREV8imCOv_CN54qbQ8.ToibvKZoyZ3 X-Yahoo-SMTP: jGL4fFmswBCDXhc_dhi0hMnBJmi0Kin0mXk- X-Rocket-Received: from [192.168.178.43] (dietmar.kuehl@77.186.41.174 with plain [188.125.69.59]) by smtp141.mail.ir2.yahoo.com with SMTP; 01 Jan 2014 02:17:02 +0000 UTC In-Reply-To: X-Mailer: Apple Mail (2.1827) X-Original-Sender: dietmar.kuehl@me.com X-Original-Authentication-Results: mx.google.com; spf=softfail (google.com: domain of transitioning dietmar.kuehl@me.com does not designate 212.82.96.39 as permitted sender) smtp.mail=dietmar.kuehl@me.com; dmarc=fail (p=NONE dis=NONE) header.from=me.com Precedence: list Mailing-list: list std-proposals@isocpp.org; contact std-proposals+owners@isocpp.org List-ID: X-Google-Group-Id: 399137483710 List-Post: , List-Help: , List-Archive: List-Subscribe: , List-Unsubscribe: , Xref: news.gmane.org gmane.comp.lang.c++.isocpp.proposals:8390 Archived-At: I realize that I'm an awful spoil-sport but the desire to generate default = versions of operator=3D=3D(), swap(), operator<(), I/O operations, and poss= ibly other operations with varying degrees of design considerations is why = I think this direction is a waste of time! Instead of even looking at propo= sals to do any of these, we should concentrate our efforts on putting a suf= ficient initial version of compile-time reflection together and provide the= necessary library components to have the corresponding operations generate= d! Since I stated this when a defaulted version of operator=3D=3D() was discus= sed at the committee meeting and proponents of a default operator=3D=3D() b= asically stated that their desire is more important than having a generic s= olution, I expect the same to happen here and won't mention it again. Howev= er, I will continue to consider any efforts of defaulting additional member= s which isn't based on a generally available reflection system a waste of t= ime. Note that this position is based on the merits of any specific proposa= l for optionally defaulting member functions but rather on wanting a genera= l solution in favour of many special solutions baked into the language. On 1 Jan 2014, at 02:42, fmatthew5876@gmail.com wrote: > Writing swap() is one of those boilerplate kinds of things that is usuall= y trivial but annoying (and error prone when you change data members but fo= rget to update swap()). >=20 > Why not allow this: >=20 > class Foo { > public: > void swap(Foo& f) =3D default; > private: > int a; > Bar b; > float c; > Baz* d; > }; >=20 > Which would be the equivalent of this: >=20 > void Foo::swap(Foo& f) { > using std::swap; > swap(a, f.a); > swap(b, f.b); > swap(c, f.c); > swap(d, f.d); > } >=20 > Any reason this wouldn't make it as a proposal? --=20 ---=20 You received this message because you are subscribed to the Google Groups "= ISO C++ Standard - Future Proposals" group. To unsubscribe from this group and stop receiving emails from it, send an e= mail to std-proposals+unsubscribe@isocpp.org. To post to this group, send email to std-proposals@isocpp.org. Visit this group at http://groups.google.com/a/isocpp.org/group/std-proposa= ls/. .