220 39018 article Path: news.gmane.org!.POSTED!not-for-mail From: Zhihao Yuan Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: RE: Re: Concepts: Investigating implicit type-name introduction Date: Sun, 08 Jul 2018 01:13:58 -0400 Lines: 56 Approved: news@gmane.org Message-ID: References: <0c0da3b7-02f4-4130-9441-5a1385864d39@isocpp.org> <07ec2785-ec90-4b72-bdbe-3cf624eac38b@isocpp.org> <77785201-b43f-4369-89d6-c8a6290f3532@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" X-Trace: blaine.gmane.org 1531026714 24586 195.159.176.226 (8 Jul 2018 05:11:54 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Sun, 8 Jul 2018 05:11:54 +0000 (UTC) Cc: 'Nicol Bolas' To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBCSKRWMD4EHBBF53Q3NAKGQE77SCHBA@isocpp.org Sun Jul 08 07:11:49 2018 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-wr1-f72.google.com ([209.85.221.72]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1fc1zB-0006HK-Dh for gclcip-std-proposals@m.gmane.org; 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[185.70.40.132]) by mx.google.com with ESMTPS id j102-v6si9817115wrj.430.2018.07.07.22.13.59 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sat, 07 Jul 2018 22:13:59 -0700 (PDT) Received-SPF: pass (google.com: domain of zy@miator.net designates 185.70.40.132 as permitted sender) client-ip=185.70.40.132; In-Reply-To: Feedback-ID: xu1i2ADzKwGyrUl8KbXpsa1PQSI0Bc21qlX1V7gpMylRDQPR42YBpWcLHW4brubvCmGM18xDo5tgsD-vWFu_cQ==:Ext:ProtonMail X-Original-Sender: zy@miator.net X-Original-Authentication-Results: mx.google.com; dkim=pass header.i=@miator.net header.s=protonmail header.b=VY7UcIcc; spf=pass (google.com: domain of zy@miator.net designates 185.70.40.132 as permitted sender) smtp.mailfrom=zy@miator.net 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:39018 Archived-At: > From: Hubert Tong > Sent: Saturday, July 7, 2018 11:27 PM > > Loss of visual anchors can lead to less readability. What's noise to some are important eyecatchers to others. > Unscoped enumerations and anonymous unions come to mind with regards to the Mergeable{I, S, O} syntax. I hope that "Mergeable I S O" is doing better since this structure is less often seen in the language. >> >> StandardLayoutType T; >> T item = producer.next(); > > Probably because it is unclear where T is bound to a concrete type in this syntax. > Is the first binding privileged? Or is this a way of saying that all deductions of T must agree on the deduced type? Or perhaps T has independent binding on each use? All deductions of T must agree on the same type, just like what template void(T a, T b) does. We can even extend this to EqualityComparable T U; T x = ...; U y = ...; >> What problem does P1141R0 solve? > Wait for it... > > auto item = producer.next(); > static_assert(StandardLayoutType); > > StandardLayoutType auto item = producer.next(); And I did not comment on that part, right? Of course there can be a consistency argument to defend the constraints on parameters, but P0915R0 did not do that since this argument would be too weak. -- Zhihao Yuan, ID lichray The best way to predict the future is to invent it. _______________________________________________ -- 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/HHziEqo3kchqTaLPVkzKZwxTTF5LkcIH239dqPJMQYMdOhB5kqiGSEKAdWQgHanaMIT2bEGiIQQGl_dW4uMnEafbovr0y5U72X8qcKN-uXQ%3D%40miator.net. .