220 23728 <56981C83.2030804@wanadoo.fr> article Path: news.gmane.org!not-for-mail From: "Vicente J. Botet Escriba" Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Re: Default swap/hash_value Date: Thu, 14 Jan 2016 23:09:07 +0100 Lines: 38 Approved: news@gmane.org Message-ID: <56981C83.2030804@wanadoo.fr> References: <569582E5.1040108@wanadoo.fr> <2ca0a385-6399-4ac3-ba0d-609628ea4ec6@isocpp.org> <5697EAD8.8080104@wanadoo.fr> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: quoted-printable X-Trace: ger.gmane.org 1452809359 26962 80.91.229.3 (14 Jan 2016 22:09:19 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Thu, 14 Jan 2016 22:09:19 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBDH67CONY4PBBBNZ4C2AKGQEDRPO4WY@isocpp.org Thu Jan 14 23:09:10 2016 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 1aJq4s-0004Ir-EY for gclcip-std-proposals@m.gmane.org; Thu, 14 Jan 2016 23:09:10 +0100 Original-Received: by mail-lb0-f197.google.com with SMTP id p10sf28169292lbo.0 for ; Thu, 14 Jan 2016 14:09:10 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=isocpp-org.20150623.gappssmtp.com; s=20150623; h=subject:to:references:from:message-id:date:user-agent:mime-version :in-reply-to:content-type:content-transfer-encoding :x-original-sender:x-original-authentication-results:reply-to :precedence:mailing-list:list-id:x-spam-checked-in-group:list-post :list-help:list-archive:list-subscribe:list-unsubscribe; bh=jQKkprBbIk1u3Dm2LAGU3o8KDmie6W1oDIdMQSpwp/M=; b=XwSLp2BySirmaw54tC6QA1DNoIAfeY9d4vTyQhZNF28m7/Ii+XWmHXZSdY032OxlDm lAGv35WQeeceydkSMkffTu1RXEfjUzHVIWIz9j2Bd0wW3W7KuzRpf0V1KdfzYDD3oczT 7vqknAjgIxhjF3t6X0AO8ZB0L6criPJCGyPa2cj9apqEKMAocJG+Cc14EQd58awrXrrZ uG5D2BU6AhWp6oPB5uLhYoTTg7FvHtGQ3T2iXMynR6Adcr6gfopOa3wzCj/L5qK28gsT 4ChQksX24Nqv97hzryvPXPwztnU05R7p1vI+OeXMupr7AwQfBnLWyN9l4SEpt X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:subject:to:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-type :content-transfer-encoding:x-original-sender :x-original-authentication-results:reply-to:precedence:mailing-list :list-id:x-spam-checked-in-group:list-post:list-help:list-archive :list-subscribe:list-unsubscribe; bh=jQKkprBbIk1u3Dm2LAGU3o8KDmie6W1oDIdMQSpwp/M=; b=FvMuM4AAVPzr/uibjUMoSYhkyW0vP2/NPLS4TtHb+xR67smuSzyKvsCVh9/uG/0HvA 2VA1I1kLf0tPzk/P+vPirRwXQK/O5Gfpi55bwZR1UHK3+c3kyHmc7edb8EtqAkqeplJH LwrR+OOkj7CJLw/v7/eMNzp1xmzGsVmMBZwSqwcb0VPu5BhJso2o6rOXlrdSxOuSF9lz TcNhalQBgvifXQQjYh1fzfselF3KIDTONGW6j9kSa4iFUP2hPRRD2+XQeuPX7krddC5f 5r2/VbSoEFgkdSSgWIK58MMUVDl+3De4Ao/wpj4keSxPMj4 X-Gm-Message-State: ALoCoQlnkZ9ENZVbke060F1Yza+Dc0Xv4x+yU3D77oaPBdAu9SArn3P2bbd3nUP94kPfMZGe6i5kQcjxy/pOo/fB/7hBvzx59Q== X-Received: by 10.25.153.145 with SMTP id b139mr759928lfe.0.1452809349934; Thu, 14 Jan 2016 14:09:09 -0800 (PST) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.28.101.84 with SMTP id z81ls1165679wmb.5.canary; Thu, 14 Jan 2016 14:09:08 -0800 (PST) X-Received: by 10.28.68.68 with SMTP id r65mr7591250wma.95.1452809348732; Thu, 14 Jan 2016 14:09:08 -0800 (PST) Original-Received: from smtp.smtpout.orange.fr (smtp06.smtpout.orange.fr. [80.12.242.128]) by mx.google.com with ESMTPS id g65si3527787wma.77.2016.01.14.14.09.08 for (version=TLS1 cipher=AES128-SHA bits=128/128); Thu, 14 Jan 2016 14:09:08 -0800 (PST) Received-SPF: neutral (google.com: 80.12.242.128 is neither permitted nor denied by best guess record for domain of vicente.botet@wanadoo.fr) client-ip=80.12.242.128; Original-Received: from new-host.home ([92.139.160.222]) by mwinf5d64 with ME id 5y971s00T4oBxcU03y98Ff; Thu, 14 Jan 2016 23:09:08 +0100 X-ME-Helo: new-host.home X-ME-Auth: dmljZW50ZS5ib3RldEB3YW5hZG9vLmZy X-ME-Date: Thu, 14 Jan 2016 23:09:08 +0100 X-ME-IP: 92.139.160.222 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.11; rv:38.0) Gecko/20100101 Thunderbird/38.4.0 In-Reply-To: X-Original-Sender: vicente.botet@wanadoo.fr X-Original-Authentication-Results: mx.google.com; spf=neutral (google.com: 80.12.242.128 is neither permitted nor denied by best guess record for domain of vicente.botet@wanadoo.fr) smtp.mailfrom=vicente.botet@wanadoo.fr Precedence: list Mailing-list: list std-proposals@isocpp.org; contact std-proposals+owners@isocpp.org List-ID: X-Spam-Checked-In-Group: std-proposals@isocpp.org 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:23728 Archived-At: Le 14/01/2016 22:02, Tomasz a =C3=A9crit : > I see the reasoning between making the generation of hash_value=20 > depended on the generation of the operator=3D=3D, as we must guarantee=20 > that o1 =3D=3D o2 implies that hash_value(o1) =3D=3D hash_value(o2). Howe= ver I=20 > do not see any correlation between generation of swap and operator=3D=3D.= =20 > If move-constructor can be generated then we will have default=20 > implementation of swap (via std::swap). I think that you should=20 > generate swap for every class that have generated move operations (no=20 > user defined: copy/move constructor, copy/move assignment and destructor)= .. > > I may be beneficial to have proper rule of six: i.e. non of following=20 > copy constructor/assigment, move constructor/assignment, swap,=20 > destructor is generated if at least on of them is defined. However=20 > this would be breaking change (as we may already have classes with=20 > swap, that uses compiler generated special functions), so I would=20 > stick to making swap depended on other five. > > Also the dependency on rule of five, would also lead of question if we=20 > should support defining swap on request via =3Ddefault. Thanks for your comments. I need to think a little bit about. I will=20 come back later on, maybe tomorrow. Vicente --=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 https://groups.google.com/a/isocpp.org/group/std-propos= als/. .