220 16917 article Path: news.gmane.org!not-for-mail From: Zhihao Yuan Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Size deduction for std::array from initializer: Comments on n3824 std::make_array Date: Mon, 9 Mar 2015 17:41:01 -0400 Lines: 56 Approved: news@gmane.org Message-ID: References: <7a747557-95d6-4484-a7d8-f18fcb05ee59@isocpp.org> <6e1bae2e-8173-4437-a45b-63cddab072e5@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-Trace: ger.gmane.org 1425937320 29811 80.91.229.3 (9 Mar 2015 21:42:00 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Mon, 9 Mar 2015 21:42:00 +0000 (UTC) To: "std-proposals@isocpp.org" Original-X-From: std-proposals+bncBCSKRWMD4EHBBHVH7CTQKGQE3RJFDTI@isocpp.org Mon Mar 09 22:41:53 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 1YV5Qu-0006Xb-BB for gclcip-std-proposals@m.gmane.org; Mon, 09 Mar 2015 22:41:52 +0100 Original-Received: by obcuz6 with SMTP id uz6sf9097928obc.3 for ; Mon, 09 Mar 2015 14:41:51 -0700 (PDT) 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:date :message-id:subject:from:to:content-type:sender: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=OAipZZx2D3D4wWDNZG7cTLCR4rWg6GXXrtQP/szvMAU=; b=DdfbywZARGXGMEPrQ2c5CeUn6y1xZ0P/XBf2LXjjA0vgW6DgeBtUAiZrLahek8jnp1 75hN7+IT2t3O8CgL2o0cuBUH++yO0g3yuM2NC3M7JBXpyKge9X53efVTFvkSQwC9q5He 8V0g/yXdThGalMZ5F8Dx3tDXZzfxaw5omGGJuBkbmjc26X0DSODoQ1ym73yyuI8dPARY PcNJ9OWAXee0UMjgGlNzcPfzgk6q3oi3/u9dDOsVGUkgQxpBOwijd8J6s5mBGGY+hoRX CGYfYE38bjXje/JtwdfgADYA3zn23S+U2XlOt5ATX4PVU/xhdXgOVo7Sn9Bq0iXKtsXd /5mg== X-Gm-Message-State: ALoCoQk9IzugK4UF2cOfiTQqH974NMOnKG35854YlQHIuA6sEhhpdtfjVZk/TMZbSMsduDL0/qjt X-Received: by 10.42.89.73 with SMTP id f9mr3008867icm.31.1425937311367; Mon, 09 Mar 2015 14:41:51 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.140.40.164 with SMTP id x33ls1744500qgx.77.gmail; Mon, 09 Mar 2015 14:41:50 -0700 (PDT) X-Received: by 10.52.94.113 with SMTP id db17mr22710888vdb.40.1425937310235; Mon, 09 Mar 2015 14:41:50 -0700 (PDT) Original-Received: from mail-s68.mailgun.info (mail-s68.mailgun.info. [184.173.153.196]) by mx.google.com with ESMTPS id ug3si10400602vcb.93.2015.03.09.14.41.50 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 09 Mar 2015 14:41:50 -0700 (PDT) Received-SPF: pass (google.com: domain of bounce+3f9131.69110-std-proposals=isocpp.org@miator.net designates 184.173.153.196 as permitted sender) client-ip=184.173.153.196; Original-Received: from mail-la0-f50.google.com (mail-la0-f50.google.com [209.85.215.50]) by mxa.mailgun.org with ESMTP id 54fe136f.7fd1f90db4f0-in1; Mon, 09 Mar 2015 21:41:03 -0000 (UTC) Original-Received: by labgd6 with SMTP id gd6so26990181lab.6 for ; Mon, 09 Mar 2015 14:41:01 -0700 (PDT) X-Received: by 10.152.28.233 with SMTP id e9mr27676157lah.3.1425937261945; Mon, 09 Mar 2015 14:41:01 -0700 (PDT) Original-Received: by 10.112.40.114 with HTTP; Mon, 9 Mar 2015 14:41:01 -0700 (PDT) In-Reply-To: <6e1bae2e-8173-4437-a45b-63cddab072e5@isocpp.org> X-Mailgun-Sid: WyI3MTBkYiIsICJzdGQtcHJvcG9zYWxzQGlzb2NwcC5vcmciLCAiNjkxMTAiXQ== Original-Sender: zy@miator.net X-Original-Sender: zy@miator.net X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of bounce+3f9131.69110-std-proposals=isocpp.org@miator.net designates 184.173.153.196 as permitted sender) smtp.mail=bounce+3f9131.69110-std-proposals=isocpp.org@miator.net; dkim=pass header.i=@miator.net 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:16917 Archived-At: On Mon, Mar 9, 2015 at 4:42 PM, Matthew Fioravante wrote: > > Accepting make_array() is assuming that this problem will either be solved > in the future or that its good enough having to live with it never being > solved. Nope. It simply means the new addition solves the problem it's trying to solve. > Or is the standards committee ok with something now that might be > obsoleted in the future should a better solution be found? > No either, because make_array has its unique use cases. For example, a language level solution cannot produce a common type out of a braced-init: std::array a = { 'a', 10 }; // boom auto a = make_array('a', 10); > > I'm concerned that we may be taking the wrong direction. If a language > feature is invented to initialize std::array (and other similar templates) > then make_array() may not be needed at all. It's committee's job to decide direction. I think we have done with the technical issues here. > The make_array() approach means having to write a new make_X() > method for each template class which might need it. Short, flexible, and works for me. > Looking at your example > implementation, writing ones own make_X() is non-trivial with all of the > edge cases covered by type_traits. > You might want to take a closer look. They are "features" which cannot be provided with language extensions. -- Zhihao Yuan, ID lichray The best way to predict the future is to invent it. ___________________________________________________ 4BSD -- http://bit.ly/blog4bsd -- --- 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. Visit this group at http://groups.google.com/a/isocpp.org/group/std-proposals/. .