220 17599 article Path: news.gmane.org!not-for-mail From: David Krauss Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Thoughts/idea about N4401 vs N4475 (regarding raw ptrs and mutables) Date: Thu, 30 Apr 2015 09:17:59 +0800 Lines: 91 Approved: news@gmane.org Message-ID: References: <5c67669c-7812-43a5-a8fd-21dcc6f8894a@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 (Mac OS X Mail 8.2 \(2098\)) Content-Type: multipart/alternative; boundary="Apple-Mail=_429D5339-73A8-4AC8-AB6D-7938F9F6D1C1" X-Trace: ger.gmane.org 1430356698 20324 80.91.229.3 (30 Apr 2015 01:18:18 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Thu, 30 Apr 2015 01:18:18 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBCW25A7E3QCRBUUFQ2VAKGQEMMCS6KQ@isocpp.org Thu Apr 30 03:18:13 2015 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-ob0-f200.google.com ([209.85.214.200]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1Ynd7E-0003rO-1g for gclcip-std-proposals@m.gmane.org; Thu, 30 Apr 2015 03:18:12 +0200 Original-Received: by obfe9 with SMTP id e9sf50878641obf.1 for ; Wed, 29 Apr 2015 18:18:10 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:content-type:message-id:mime-version :subject:date:references:to:in-reply-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; bh=g9ZUp02FsVtojT/i6jRG64GIt+7UgVzri+qkOTMf2vQ=; b=jE15RoT6I6ZHJfXlxCX2t61x8GNQERaWj4FMO0DHPTlMmb0CH2c71lT9D+XumWsaMm 6OW93CtJTIupQVuRz4n3HUblwSYKVb+upJT9JZwYooTGPXJGdcK5SXL41MkWssj8wCpp gC1DZyGqTvGvRmuBD7LuuB/9vGkzRTkl6MrWO54zP+Yaq9PGstKmGFNODq6M50jMHeCH AvGnMASabAWrjkjwzDXP/0ZGMhOinzaxK04Qmb3ctQwiVrM8dupgfe5+W4qvt2KoQr2L 9ms3/KOE/RNuc4WhqANvY+F/mRmCYNPrEHThjRKiuwk+qVjwhbVJ6sQx6kjECXZx+r2C 2/qA== X-Gm-Message-State: ALoCoQl3AxX86qaofJhCJmPdRwp/WChBXfdEygsAJn7fVf1UjaagI+TGY/LnDia7iIP/SYJsx7ow X-Received: by 10.182.22.138 with SMTP id d10mr2843342obf.37.1430356690608; Wed, 29 Apr 2015 18:18:10 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.50.79.131 with SMTP id j3ls6623igx.38.canary; Wed, 29 Apr 2015 18:18:09 -0700 (PDT) X-Received: by 10.70.54.164 with SMTP id k4mr3368438pdp.61.1430356689852; Wed, 29 Apr 2015 18:18:09 -0700 (PDT) Original-Received: from mail-pa0-x22f.google.com (mail-pa0-x22f.google.com. [2607:f8b0:400e:c03::22f]) by mx.google.com with ESMTPS id xg2si1059342pbb.106.2015.04.29.18.18.09 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 29 Apr 2015 18:18:09 -0700 (PDT) Received-SPF: pass (google.com: domain of potswa@gmail.com designates 2607:f8b0:400e:c03::22f as permitted sender) client-ip=2607:f8b0:400e:c03::22f; Original-Received: by pabsx10 with SMTP id sx10so43686490pab.3 for ; Wed, 29 Apr 2015 18:18:09 -0700 (PDT) X-Received: by 10.66.231.42 with SMTP id td10mr3351530pac.98.1430356689565; Wed, 29 Apr 2015 18:18:09 -0700 (PDT) Original-Received: from [172.20.10.2] ([121.54.44.89]) by mx.google.com with ESMTPSA id zf1sm395515pbc.43.2015.04.29.18.18.05 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Wed, 29 Apr 2015 18:18:08 -0700 (PDT) In-Reply-To: X-Mailer: Apple Mail (2.2098) X-Original-Sender: potswa@gmail.com X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of potswa@gmail.com designates 2607:f8b0:400e:c03::22f as permitted sender) smtp.mail=potswa@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:17599 Archived-At: --Apple-Mail=_429D5339-73A8-4AC8-AB6D-7938F9F6D1C1 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=UTF-8 > On 2015=E2=80=9304=E2=80=9329, at 5:56 PM, lie4pan1 = wrote: >=20 > After some thoughts I think any '__cookie__' non-mutable members should s= uppress generating such said defaulted operators What=E2=80=99s the point of declaring a __cookie__ when you can just declar= e the operator as deleted? If we treat all pointers as implicitly __cookie_= _, your position maps to the status quo, except that mutable members can be= included, which is a very niche case. N4475 already notes the ambiguity around mutable members. Oddly it overlook= s the alternative of letting them suppress the implicit declaration, but le= aving the implicit definition available by =3D default. That=E2=80=99s what= I would favor. Letting a mutable member participate in operator =3D=3D sounds like bad des= ign. If you really want that, and there are lots of members, you can factor= the mutable and non-mutable members into two base classes, and then a deri= ved class can compose its operator from from the base class implicit defini= tions. --=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/. --Apple-Mail=_429D5339-73A8-4AC8-AB6D-7938F9F6D1C1 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=UTF-8
On 2015=E2=80=9304= =E2=80=9329, at 5:56 PM, lie4pan1 <lie4pan1@gmail.com> wrote:

After some thoughts I think any '__cookie= __' non-mutable members should suppress generating such said defaulted oper= ators

What=E2= =80=99s the point of declaring a __cookie= __ when you can just declare the operator as deleted? If we tre= at all pointers as implicitly __cookie__, your position maps to the status quo, except th= at mutable members can be included, which is a very niche case.

N4475 already notes the ambi= guity around mutable members. Oddly it overlooks the alternative of letting= them suppress the implicit declaration, but leaving the implicit definitio= n available by =3D default. That= =E2=80=99s what I would favor.

Letting a mutable member participate in operator =3D=3D sounds like bad design. If you really w= ant that, and there are lots of members, you can factor the mutable and non= -mutable members into two base classes, and then a derived class can compos= e its operator from from the base class implicit definitions.<= /html>

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