220 27282 article Path: news.gmane.org!not-for-mail From: Tony V E Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: What should the semantic of wrapper classes be? Date: Tue, 26 Jul 2016 18:34:36 -0400 Lines: 99 Approved: news@gmane.org Message-ID: References: <5b59502b-2a34-46dd-990e-1a748301018d@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: multipart/alternative; boundary=001a114b703a754f5e05389181a0 X-Trace: ger.gmane.org 1469572480 5761 80.91.229.3 (26 Jul 2016 22:34:40 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Tue, 26 Jul 2016 22:34:40 +0000 (UTC) To: Standard Proposals Original-X-From: std-proposals+bncBCUZ5QWKNQIP3SW7XQCRUBBEDE5NS@isocpp.org Wed Jul 27 00:34:40 2016 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-lf0-f69.google.com ([209.85.215.69]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1bSAvv-0008CW-4N for gclcip-std-proposals@m.gmane.org; Wed, 27 Jul 2016 00:34:39 +0200 Original-Received: by mail-lf0-f69.google.com with SMTP id p85sf2452683lfg.3 for ; Tue, 26 Jul 2016 15:34:38 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=isocpp-org.20150623.gappssmtp.com; s=20150623; h=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:x-spam-checked-in-group:list-post :list-help:list-archive:list-subscribe:list-unsubscribe; bh=DeinmjYF6GanuR8DPDb5CbqEyIlDUFwWOf03cGEIh10=; b=EowbE7Vm+j8fK/d5JNfGc7EgbQ/2DL9Mtn7R/7tosvp6Y72J6dGKSQrJN4DuaInb8W lj38BZX9K353FS9O1hHC2GqvhjH1S8BX3BYxc86y+xOdizHaAPgoPSY8B6M0la76+uaB UUNYC+W/clSRRz60rg0Bc4BmGNkFWNcPg/yTTY0pvCfZSbxzo0sMRZOX4C3B9e/O4W/m F0DvFQt1Jv5cyfRdGpxKVABspAzG42OquDivTO+5Pm5zf3NzZs1PTp4QLbBlzBKScsY3 oAbXcpwOdhc9FJs7pe9nWNRoEkjRSy4ICQY/hHWXkmFn7QOREksvFPVRoPKJ7cureWCl S6WQ== 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:x-spam-checked-in-group:list-post:list-help:list-archive :list-subscribe:list-unsubscribe; bh=DeinmjYF6GanuR8DPDb5CbqEyIlDUFwWOf03cGEIh10=; b=F4xmZ4Cq3olPOYueP3EePIfpiodi0n9btwa7pkUJQ9dEQAQTN4Bi4ImRaTLjDVXLaw 2LU8SkudloOOzmpUqpGdwet6qNg7YtyKsaliGECYmj9M5nUjkp38hNFagW8XnpxAgjt2 MjHYmUA6HU40ikXtZe6HmwYjSDTWXVSJjgj8NBKVj03TZrOY3SnNGlrurZOJiYUbjTso VTm1V7Uls0Bj/nEP41bgwD2VlK4aPcR5XO8MbWEaYBzg9Tvv+9m70dulsChdUXeXwm8m Ljrap3LzjANEJdASCaZJsrFvP725B6T+NCc3uEjfiF9pXZgPg8fL55smvC3nTLTPqy/A Um7g== X-Gm-Message-State: AEkoouu8ZmN3cSrATACEz2r2AkEPsSKbGyzZyiuD57eNwyFztYx+51R8YRYNKiNwmsLOIA== X-Received: by 10.28.31.15 with SMTP id f15mr3777802wmf.5.1469572478412; Tue, 26 Jul 2016 15:34:38 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.28.35.77 with SMTP id j74ls961296wmj.14.canary; Tue, 26 Jul 2016 15:34:37 -0700 (PDT) X-Received: by 10.28.154.21 with SMTP id c21mr29478539wme.63.1469572477406; Tue, 26 Jul 2016 15:34:37 -0700 (PDT) Original-Received: from mail-wm0-x22c.google.com (mail-wm0-x22c.google.com. [2a00:1450:400c:c09::22c]) by mx.google.com with ESMTPS id d62si31300479wmd.27.2016.07.26.15.34.37 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 26 Jul 2016 15:34:37 -0700 (PDT) Received-SPF: pass (google.com: domain of tvaneerd@gmail.com designates 2a00:1450:400c:c09::22c as permitted sender) client-ip=2a00:1450:400c:c09::22c; Original-Received: by mail-wm0-x22c.google.com with SMTP id o80so36497006wme.1 for ; Tue, 26 Jul 2016 15:34:37 -0700 (PDT) X-Received: by 10.28.61.11 with SMTP id k11mr28981044wma.34.1469572476913; Tue, 26 Jul 2016 15:34:36 -0700 (PDT) Original-Received: by 10.28.131.143 with HTTP; Tue, 26 Jul 2016 15:34:36 -0700 (PDT) In-Reply-To: <5b59502b-2a34-46dd-990e-1a748301018d@isocpp.org> X-Original-Sender: tvaneerd@gmail.com X-Original-Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com; spf=pass (google.com: domain of tvaneerd@gmail.com designates 2a00:1450:400c:c09::22c as permitted sender) smtp.mailfrom=tvaneerd@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-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:27282 Archived-At: --001a114b703a754f5e05389181a0 Content-Type: text/plain; charset=UTF-8 On Tue, Jul 26, 2016 at 2:05 AM, Vincent Reverdy wrote: > Hello. > > Please find the document attached. > It's not really a proposal... but we need help on this question and people > really don't seem to agree. > So... any help, advice, opinion is welcome. > I would say value makes no sense. A value is a value. All values are const. 17 is const. It is always 17. What may be NOT const is a variable holding the value 17. So value should not exist. It should be collapsed to value. const value is fine. pointer makes sense, because it is referring to a value living somewhere else. But for value I assume the T lives within value. Alternatively, value should work the same as const value. What does auto do? const int x = 17; auto y = x; // y is not const? What does optional do? Based on the "essence" of optional, if it worked at all, it should allow you to assign to it once (first assign is construction) and then fail further assignments. But I'm pretty sure we didn't make it throw an exception in that case. -- 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. To view this discussion on the web visit https://groups.google.com/a/isocpp.org/d/msgid/std-proposals/CAOHCbitD0Hc9yt9q-x3vhiULYpZi02aVs0QqvAMdgxDjUHqQ5Q%40mail.gmail.com. --001a114b703a754f5e05389181a0 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable


On Tue, Jul 26, 2016 at 2:05 AM, Vincent Reverdy <= vince.rev@gmail.co= m> wrote:
= Hello.

Please find the document attached.
It's not really a p= roposal... but we need help on this question and people really don't se= em to agree.
So... any help, advice, opinion is welcome.


I would say value<= const T> makes no sense.

A value= is a value.=C2=A0 All values are const.=C2=A0 17 is const.=C2=A0 It is alw= ays 17.
What may be NOT const is a vari= able holding the value 17.

So value= <const T> should not exist.=C2=A0 It should be collapsed to value<= T>.=C2=A0 const value<T> is fine.

pointer<const T> makes sense, because it is referring to a va= lue living somewhere else.
But for valu= e<T> I assume the T lives within value<T>.

Alternatively, value<const T> should work the sam= e as const value<T>.

What doe= s auto do?

const int x =3D 17;
<= /div>
auto y =3D x; // y is not const?
<= div class=3D"gmail_extra">
What does op= tional<const T> do?

Based on = the "essence" of optional, if it worked at all, it should allow y= ou to assign to it once (first assign is construction) and then fail furthe= r assignments.
But I'm pretty sure = we didn't make it throw an exception in that case.



--
You received this message because you are subscribed to the Google Groups &= quot;ISO C++ Standard - Future Proposals" group.
To unsubscribe from this group and stop receiving emails from it, send an e= mail to std-proposa= ls+unsubscribe@isocpp.org.
To post to this group, send email to std-proposals@isocpp.org.
To view this discussion on the web visit htt= ps://groups.google.com/a/isocpp.org/d/msgid/std-proposals/CAOHCbitD0Hc9yt9q= -x3vhiULYpZi02aVs0QqvAMdgxDjUHqQ5Q%40mail.gmail.com.
--001a114b703a754f5e05389181a0-- .