220 2779 <5115987B.5000507@gmail.com> article Path: news.gmane.org!not-for-mail From: =?ISO-8859-1?Q?Mikael_Kilpel=E4inen?= Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Re: A proposal to add swap traits to the standard library Date: Sat, 09 Feb 2013 01:29:47 +0100 Lines: 38 Approved: news@gmane.org Message-ID: <5115987B.5000507@gmail.com> References: <713d1419-a642-408c-b3ba-44d1a17c2bb8@isocpp.org> <511227BD.9010306@gmail.com> <536643f8-e7bd-447c-8515-6829c42f8425@isocpp.org> <51127060.7010505@gmail.com> <8AB4D2A8-9E07-47C9-9F72-E5DD6D11B1FA@gmail.com> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed X-Trace: ger.gmane.org 1360369796 6429 80.91.229.3 (9 Feb 2013 00:29:56 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Sat, 9 Feb 2013 00:29:56 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBDHYRTPW4EBRBA5R22EAKGQEWVGAUEA@isocpp.org Sat Feb 09 01:30:17 2013 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-bk0-f69.google.com ([209.85.214.69]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1U3yKd-0000qQ-30 for gclcip-std-proposals@m.gmane.org; Sat, 09 Feb 2013 01:30:15 +0100 Original-Received: by mail-bk0-f69.google.com with SMTP id q16sf4569616bkw.8 for ; Fri, 08 Feb 2013 16:29:56 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=x-received:x-beenthere:x-received:x-received:received-spf :x-received:message-id:date:from:user-agent:mime-version:to:subject :references:in-reply-to:x-original-sender :x-original-authentication-results:reply-to:precedence:mailing-list :list-id:x-google-group-id:list-post:list-help:list-archive :list-subscribe:list-unsubscribe:content-type; bh=DULyrosNnycUUTGE9m1AJ57JyOIwUF6tzedrdt3Jzb8=; b=RmzDxknkLNVabnBT6rd+ho8zw4fG52oPJJIsBrSyWggg3umBvq9T5ZYOW5xooiztLQ 5/4aQnT4rbfzpLtcrfbVo3+kj/dIZK+Y1e3ON80Yb/WXuXuA6d0Oib4li5dk+FlcYPiY fhDG3qvvlE3zJqWMe6uCWdyZt+mfRQVgMAIoWU4zyxJfOVUoTXWRLsk6q1uztgEFYWOr L4aCL9wXL+bJBiJfheJAWwIPapCzyfM+CZDHuYp/Ykod9/xNVoi/BdTlCRGf9bh+ZePH GSH2jVbn0Zt+QZbfxJzsLznwtWsAV9lnOTO1y3 X-Received: by 10.180.8.132 with SMTP id r4mr735505wia.0.1360369796104; Fri, 08 Feb 2013 16:29:56 -0800 (PST) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.180.84.67 with SMTP id w3ls447656wiy.53.canary; Fri, 08 Feb 2013 16:29:55 -0800 (PST) X-Received: by 10.204.5.140 with SMTP id 12mr1993093bkv.18.1360369795585; Fri, 08 Feb 2013 16:29:55 -0800 (PST) X-Received: by 10.204.5.140 with SMTP id 12mr1993092bkv.18.1360369795547; Fri, 08 Feb 2013 16:29:55 -0800 (PST) Original-Received: from mail-bk0-f43.google.com (mail-bk0-f43.google.com [209.85.214.43]) by mx.google.com with ESMTPS id gy11si23676159bkc.60.2013.02.08.16.29.54 (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Fri, 08 Feb 2013 16:29:54 -0800 (PST) Received-SPF: pass (google.com: domain of mikael.kilpelainen@gmail.com designates 209.85.214.43 as permitted sender) client-ip=209.85.214.43; Original-Received: by mail-bk0-f43.google.com with SMTP id jm19so1907955bkc.2 for ; Fri, 08 Feb 2013 16:29:54 -0800 (PST) X-Received: by 10.205.136.205 with SMTP id il13mr533812bkc.93.1360369794351; Fri, 08 Feb 2013 16:29:54 -0800 (PST) Original-Received: from [192.168.1.72] (koln-4db42936.pool.mediaWays.net. [77.180.41.54]) by mx.google.com with ESMTPS id fs20sm10653244bkc.8.2013.02.08.16.29.53 (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Fri, 08 Feb 2013 16:29:53 -0800 (PST) User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:17.0) Gecko/20130107 Thunderbird/17.0.2 In-Reply-To: <8AB4D2A8-9E07-47C9-9F72-E5DD6D11B1FA@gmail.com> X-Original-Sender: mikael.kilpelainen@gmail.com X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of mikael.kilpelainen@gmail.com designates 209.85.214.43 as permitted sender) smtp.mail=mikael.kilpelainen@gmail.com; dkim=pass header.i=@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:2779 Archived-At: 9.2.2013 0:36, Howard Hinnant kirjoitti: > For me here is the poster-child for heterogeneous swap: > > #include > #include > > int main() > { > std::vector v(1); > bool b = true; > swap(b, v[0]); > std::cout << v[0] << '\n'; > } > > The standard doesn't say this should work, but imho the standard is broken in that regard. It works in libc++ just as a personal expression of defiance. :-) Not sure if/where else. I agree something like this should work, but vector is rather special anyhow. The fix seems quite trivial for this specific case though, did you have some more generic problem in mind which i just failed to see? > > I don't know of a case where a heterogeneous swap is useful for being explicitly heterogeneous. It is usually useful as trying to masquerade as a homogeneous swap. > I think so too. Can you think of other "common" examples than vector? Mikael -- --- 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/?hl=en. .