220 8321 article Path: news.gmane.org!not-for-mail From: "Billy O'Neal" Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Proposal: Default swap operation Date: Tue, 31 Dec 2013 17:53:46 -0800 Lines: 145 Approved: news@gmane.org Message-ID: References: Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: multipart/alternative; boundary=089e0111be76ed4b8304eedef4a3 X-Trace: ger.gmane.org 1388541261 23684 80.91.229.3 (1 Jan 2014 01:54:21 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Wed, 1 Jan 2014 01:54:21 +0000 (UTC) To: std-proposals Original-X-From: std-proposals+bncBDKLBLVE6ADBBUXKRWLAKGQEYWTZ5VY@isocpp.org Wed Jan 01 02:54:29 2014 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-pa0-f71.google.com ([209.85.220.71]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1VyB0u-0005Wh-7g for gclcip-std-proposals@m.gmane.org; Wed, 01 Jan 2014 02:54:28 +0100 Original-Received: by mail-pa0-f71.google.com with SMTP id kp14sf36795753pab.6 for ; Tue, 31 Dec 2013 17:54:27 -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:in-reply-to:references:from:date :message-id:subject: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; bh=d1uaFgon2+z1xgEQojPjA+sqAQdnxGOWFymHPAhPLqg=; b=YGVCVwQpQ7PBBKmQM1XlCbu7EfUyU6/3UCle+5EfEQ2izOikG0vOZ4bhTqj6RRL3/8 ITVTN8wpMEU6CDBuXJyHso+uA2LvFtzDuransqsh2EyIy7ADtbi3U4BLodYbhNNNrZHG KaTXkOQMOIsKXOOWhItTHvDyjaAqwbPmI7VokChwJvOhqM5rWEWSJD29bbQrgktBsd1l mcUlbSAmOjAB+PwxpQ063LX099mkD4GVZsqdhjelwtRRr70U8dZG6tBdyGi77yue7myl yWewW99PkD0HRslnTw1H3aUxu/XYSFBgELMWrL2ZgB4UhJDEYcgbHNUSTATuHCpu/m18 LbUQ== X-Gm-Message-State: ALoCoQkly/JWEVkHVMNn8vZfMrdY96OyoXP2tM7LmHSGVmDZ7e7BHbv320Zdg9AutDVxlXqSap2n X-Received: by 10.66.228.67 with SMTP id sg3mr9234600pac.25.1388541267069; Tue, 31 Dec 2013 17:54:27 -0800 (PST) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.49.82.49 with SMTP id f17ls3900574qey.54.gmail; Tue, 31 Dec 2013 17:54:26 -0800 (PST) X-Received: by 10.236.105.236 with SMTP id k72mr52406362yhg.30.1388541266489; Tue, 31 Dec 2013 17:54:26 -0800 (PST) Original-Received: from mail-ob0-x22f.google.com (mail-ob0-x22f.google.com [2607:f8b0:4003:c01::22f]) by mx.google.com with ESMTPS id z21si26854768yhb.74.2013.12.31.17.54.26 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Tue, 31 Dec 2013 17:54:26 -0800 (PST) Received-SPF: pass (google.com: domain of billy.oneal@gmail.com designates 2607:f8b0:4003:c01::22f as permitted sender) client-ip=2607:f8b0:4003:c01::22f; Original-Received: by mail-ob0-f175.google.com with SMTP id uz6so13134819obc.6 for ; Tue, 31 Dec 2013 17:54:26 -0800 (PST) X-Received: by 10.182.88.202 with SMTP id bi10mr25188857obb.52.1388541266183; Tue, 31 Dec 2013 17:54:26 -0800 (PST) Original-Received: by 10.182.87.37 with HTTP; Tue, 31 Dec 2013 17:53:46 -0800 (PST) In-Reply-To: X-Original-Sender: billy.oneal@gmail.com X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of billy.oneal@gmail.com designates 2607:f8b0:4003:c01::22f as permitted sender) smtp.mail=billy.oneal@gmail.com; dkim=pass header.i=@gmail.com; dmarc=pass (p=NONE dis=NONE) header.from=gmail.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:8321 Archived-At: --089e0111be76ed4b8304eedef4a3 Content-Type: text/plain; charset=ISO-8859-1 I don't think this is a good idea -- if a type is going to provide swap, normally it must do so in a non-throwing way. I'd worry that people would just add it in without thinking only to break normal assumptions of what swap does. The other issue here is that "using std::swap" would require including ... Billy O'Neal https://github.com/BillyONeal/ http://stackoverflow.com/users/82320/billy-oneal Malware Response Instructor - BleepingComputer.com On Tue, Dec 31, 2013 at 5:42 PM, wrote: > Writing swap() is one of those boilerplate kinds of things that is usually > trivial but annoying (and error prone when you change data members but > forget to update swap()). > > Why not allow this: > > class Foo { > public: > void swap(Foo& f) = default; > private: > int a; > Bar b; > float c; > Baz* d; > }; > > Which would be the equivalent of this: > > void Foo::swap(Foo& f) { > using std::swap; > swap(a, f.a); > swap(b, f.b); > swap(c, f.c); > swap(d, f.d); > } > > Any reason this wouldn't make it as a proposal? > > -- > > --- > 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 > email 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-proposals/. > -- --- You received this message because you are subscribed to the Google Groups "ISO C++ Standard - Future Proposals" group. 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I don't think this is a good idea -- if a type is goin= g to provide swap, normally it must do so in a non-throwing way. I'd wo= rry that people would just add it in without thinking only to break normal = assumptions of what swap does.

The other issue here is that "using std::swap" wou= ld require including <algorithm>...

Malware Response Instructor - BleepingComputer.com


On Tue, Dec 31, 2013 at 5:42 PM, <fmatthew5876@gmail.com> wrote:
Writing swap() is one of those boilerplate kinds of things= that is usually trivial but annoying (and error prone when you change data= members but forget to update swap()).

Why not allow thi= s:

class Foo {
=A0 public:
=A0 =A0 voi= d swap(Foo& f) =3D default;
=A0 private:
=A0 =A0 in= t a;
=A0 =A0 Bar b;
=A0 =A0 float c;
=A0 =A0 = Baz* d;
};

Which would be the equivalent of this:

void Foo::swap(Foo& f) {
=A0 using std::swap;
=A0= swap(a, f.a);
=A0 swap(b, f.b);
=A0 swap(c, f.c);
=A0 swap(d, f.d);
}

Any reason this woul= dn't make it as a proposal?

--
=A0
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