220 33783 <3784a92f-9045-e0e8-df9f-51a68f66ac99@gmail.com> article Path: news.gmane.org!.POSTED!not-for-mail From: Matthew Woehlke Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: properties? Date: Thu, 10 Aug 2017 10:05:12 -0400 Lines: 35 Approved: news@gmane.org Message-ID: <3784a92f-9045-e0e8-df9f-51a68f66ac99@gmail.com> References: <6ed2bd55-5538-418f-8f1a-263a9958babd@isocpp.org> <9979b017-fc21-445f-a1d1-0f55f8e7bf3d@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 1502373936 722 195.159.176.226 (10 Aug 2017 14:05:36 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Thu, 10 Aug 2017 14:05:36 +0000 (UTC) User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.1 Cc: bop@gmb.dk To: std-proposals@isocpp.org, Ville Voutilainen Original-X-From: std-proposals+bncBC37LBFWUIFBBG6QWHGAKGQEKETLPJA@isocpp.org Thu Aug 10 16:05:28 2017 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-ua0-f200.google.com ([209.85.217.200]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1dfo5G-0007Vq-C0 for gclcip-std-proposals@m.gmane.org; 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[66.194.253.20]) by smtp.googlemail.com with ESMTPSA id c5sm3483985qkd.27.2017.08.10.07.05.13 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 10 Aug 2017 07:05:13 -0700 (PDT) Original-Newsgroups: gmane.comp.lang.c++.isocpp.proposals In-Reply-To: Content-Language: en-US X-Original-Sender: mwoehlke.floss@gmail.com X-Original-Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=b1Yzbawx; spf=pass (google.com: domain of mwoehlke.floss@gmail.com designates 2607:f8b0:400d:c09::243 as permitted sender) smtp.mailfrom=mwoehlke.floss@gmail.com; dmarc=pass (p=NONE sp=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:33783 Archived-At: On 2017-08-10 02:35, Ville Voutilainen wrote: > On 10 August 2017 at 09:19, Nicol Bolas wrote: >> On Wednesday, August 9, 2017 at 10:12:36 PM UTC-4, Bo Persson wrote: >>> On 2017-08-09 19:32, Evan Teran wrote: >>>> std::cout <>> >>> This could already work if you just add () to each use of data. :-) >> >> Would it? Would this: >> >> some_function(value.data()); >> >> Would that allow `some_function` to set `data`'s value? To do that, you >> would need to make `data()` return a proxy object, which can be converted >> into the appropriate type, but can also be assigned to the appropriate type >> and otherwise treated exactly like a reference to the other type. >> >> That's hardly "just" adding something. > > Gee, data() could just return a reference. ....which is only possible if it is okay for the user to directly assign to the underlying data member. If something non-trivial needs to happen when the property is assigned, then no, you'd need to return a proxy object. (And, alas, some_function would need to be a template.) -- Matthew -- 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/3784a92f-9045-e0e8-df9f-51a68f66ac99%40gmail.com. .