220 11809 <335948E6-8140-4673-B958-930356A52070@gmail.com> article Path: news.gmane.org!not-for-mail From: David Krauss Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: N4078: Rvalue reference overloads for value() method returns object by value Date: Thu, 10 Jul 2014 22:58:26 +0800 Lines: 108 Approved: news@gmane.org Message-ID: <335948E6-8140-4673-B958-930356A52070@gmail.com> References: <4DA018C3-2327-4F55-B7F8-7988EC7B789A@gmail.com> <1a858a77-310b-4591-aaf5-960c40d9f5fc@isocpp.org> <66AF41C1-CB37-4311-98EA-D47DBC6068DC@gmail.com> <66c38b61-7a95-4ace-b34f-2346bb334fb9@isocpp.org> <6F4B3C72-9962-48DC-8527-0C89EA1B9710@gmail.com> <35873CE5-ED8C-4C03-A6A1-E4132DECD91F@gmail.com> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 (Mac OS X Mail 7.3 \(1878.6\)) Content-Type: multipart/alternative; boundary="Apple-Mail=_36C7DCE8-AF9A-4998-B313-76D861386C7E" X-Trace: ger.gmane.org 1405004331 22686 80.91.229.3 (10 Jul 2014 14:58:51 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Thu, 10 Jul 2014 14:58:51 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBCW25A7E3QCRBIGU7KOQKGQEV4BGRLY@isocpp.org Thu Jul 10 16:58:43 2014 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-qc0-f198.google.com ([209.85.216.198]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1X5Fo2-0004kS-4H for gclcip-std-proposals@m.gmane.org; Thu, 10 Jul 2014 16:58:42 +0200 Original-Received: by mail-qc0-f198.google.com with SMTP id m20sf30853678qcx.9 for ; Thu, 10 Jul 2014 07:58:41 -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: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:content-type; bh=VM6yw2RWArBSsoimp1Dmvj+cwfQwIamjiUl0gsRfEBI=; b=AptmgQQfSF5SSpcxc2I9RNfr70J7fa3b+GZPqYAnDiU1a/tbPtrUQX7lmJmOiqZvLg Eqp9+pYXTS4yVSVYaAPdwqqNae4JNDz3b3p1/laSOYAAv8OHXR2cMi+jBvKjSouau83O Qck0QN6jsRWHHDmJV3nuEq43eZ5LzE20kfI2OSm1mmxk1lC3RoN0HJ9RJ0qtr+DK5nax WDVVED1y8X/HCU2uSitdAWfkY3uwpcsO6iLtqxcRZ0obavu8fOpRfYHFlw8oRL8SecuJ KL7eiAKa8UPbrbjCQIB8Tc2uFzONpqu+XeqnMBjM/MIy9N73gyBtJHcxdyy4VHqwstVT rLRg== X-Gm-Message-State: ALoCoQmQubdc9VDYmn/cWCAIOuRAESv30+4eXGwFPXZ0279qYe3enrMkyDE3BhwOMuuBlmCW3AzD X-Received: by 10.236.66.178 with SMTP id h38mr12180862yhd.44.1405004321283; Thu, 10 Jul 2014 07:58:41 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.50.43.163 with SMTP id x3ls201871igl.2.gmail; Thu, 10 Jul 2014 07:58:40 -0700 (PDT) X-Received: by 10.50.33.17 with SMTP id n17mr22032624igi.15.1405004320685; Thu, 10 Jul 2014 07:58:40 -0700 (PDT) Original-Received: from mail-ie0-x235.google.com (mail-ie0-x235.google.com [2607:f8b0:4001:c03::235]) by mx.google.com with ESMTPS id t10si13553989igh.36.2014.07.10.07.58.40 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Thu, 10 Jul 2014 07:58:40 -0700 (PDT) Received-SPF: pass (google.com: domain of potswa@gmail.com designates 2607:f8b0:4001:c03::235 as permitted sender) client-ip=2607:f8b0:4001:c03::235; Original-Received: by mail-ie0-f181.google.com with SMTP id rp18so2181525iec.40 for ; Thu, 10 Jul 2014 07:58:40 -0700 (PDT) X-Received: by 10.50.66.179 with SMTP id g19mr7052610igt.34.1405004320485; Thu, 10 Jul 2014 07:58:40 -0700 (PDT) Original-Received: from [172.20.10.2] ([121.54.54.43]) by mx.google.com with ESMTPSA id tp2sm25768984igb.7.2014.07.10.07.58.31 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Thu, 10 Jul 2014 07:58:39 -0700 (PDT) In-Reply-To: X-Mailer: Apple Mail (2.1878.6) X-Original-Sender: potswa@gmail.com X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of potswa@gmail.com designates 2607:f8b0:4001:c03::235 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:11809 Archived-At: --Apple-Mail=_36C7DCE8-AF9A-4998-B313-76D861386C7E Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=ISO-8859-1 On 2014-07-10, at 10:44 PM, Ville Voutilainen = wrote: > On 10 July 2014 17:24, David Krauss wrote: >> A return-by-reference from a non-ref-discriminated accessor devolving to >> return-by-copy would regress legacy code, but that doesn't make such lib= rary >> behavior semantically sound from a modern point of view. >=20 > The "modern point of view" should include the forwarding concerns, which > are not limited to the performance of emplace. Absolutely. I'm have an interest in this because I write this kind of code. >> The rvalue-ref-qualified signatures need to return T&& instead of T. >> LEWG needs an NB comment >> to be able to make that fix for Fundamentals v1, and I'm going to provid= e >> them >> with one. >>=20 >>=20 >> The rvalue-ref-qualified signatures of what, std::optional? That's not a >=20 > Uh.. yes. That's the topic of this thread. Maybe I don't understand the standardization process, but wouldn't the cons= ervative solution be to simply roll that back from N4078, so optional behav= es the same as everything else? Adding a new feature in a particular way do= esn't fall into the category of legacy support. Optional is attempting to be the most perfect proxy class ever designed, an= d it's pushing the envelope in a way that fundamentally disagrees with stan= dardization. Simply put, it's churning too much. The debate can't be just about optional, even just in this thread, because = the rest of the library is going to have to follow suit. --=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=_36C7DCE8-AF9A-4998-B313-76D861386C7E Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=ISO-8859-1
On 2014&= ndash;07–10, at 10:44 PM, Ville Voutilainen <ville.voutilainen@gmail.com> wrote:
<= br class=3D"Apple-interchange-newline">
On 10 July= 2014 17:24, David Krauss <potswa@gm= ail.com> wrote:
A return-by-reference f= rom a non-ref-discriminated accessor devolving to
return-by-copy would r= egress legacy code, but that doesn’t make such library
behavior se= mantically sound from a modern point of view.

The "mode= rn point of view" should include the forwarding concerns, which
are not = limited to the performance of emplace.

= Absolutely. I’m have an interest in this because I write this kind of= code.

The rva= lue-ref-qualified signatures need to return T&& instead of T.
LE= WG needs an NB comment
to be able to make that fix for Fundamentals v1, = and I'm going to provide
them
with one.


The rvalue-ref-qua= lified signatures of what, std::optional? That’s not a

Uh.. yes. That's the topic of this thread.

<= /div>
Maybe I don’t understand the standardization process, but = wouldn’t the conservative solution be to simply roll that back from N= 4078, so optional behaves the same as everything else? Adding a new feature= in a particular way doesn’t fall into the category of legacy support= ..

Optional is attempting to be the most perfect proxy cl= ass ever designed, and it’s pushing the envelope in a way that fundam= entally disagrees with standardization. Simply put, it’s churning too= much.

The debate can’t be just about optional, even just in this thread, because the res= t of the library is going to have to follow suit.

--

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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.
Visit this group at http://groups.google.com/a/isocpp.org/group/std-proposals/<= /a>.
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