220 13657 article Path: news.gmane.org!not-for-mail From: =?ISO-8859-1?Q?Daniel_Kr=FCgler?= Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Generic std::size, a la std::begin Date: Sat, 4 Oct 2014 14:21:15 +0200 Lines: 48 Approved: news@gmane.org Message-ID: References: <8808df5e-62c4-459d-acd9-00e63adb9476@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 X-Trace: ger.gmane.org 1412428504 985 80.91.229.3 (4 Oct 2014 13:15:04 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Sat, 4 Oct 2014 13:15:04 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBCT7RVFA4QORBPGMX6QQKGQE72GWRQQ@isocpp.org Sat Oct 04 15:15:00 2014 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-wg0-f69.google.com ([74.125.82.69]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1XaPAp-0008UE-Sx for gclcip-std-proposals@m.gmane.org; Sat, 04 Oct 2014 15:14:59 +0200 Original-Received: by mail-wg0-f69.google.com with SMTP id b13sf1547388wgh.4 for ; Sat, 04 Oct 2014 06:14:59 -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: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=nZL+SCst6Lux6Nlvo3NyqdGT37Gsnw+fAdrnHcr0AFE=; b=R2v4STXcxAos0OZIm4yQFRNuRJsccLsoRNfHu7HEwuJUtJsgGftTxnlXHYXAzLJHSo gg6mMzMU3yok4Udg84wGrw0NcvneKkxv7EIzUIvxoTDx6AQ2u+6ZbQ+Lxt/n1hTl/FTI +UrrdRys84JYBwkGQip0IkiO8F1JZV96kHIFnl4Eumio+X0QrpIsLHewjxGiCEyQ10Qk erF+kQ9VtDP7/QHftUEjSGnoF1i0x//+4VL+0DSlQ+6OmVLC7gfxgCKKbMFihBfjo7gs LtaYkU7KS3krxnnEOmnDBQMLU8PqSruwjDq/Lmzgn2FERHpfBIHNGHyMbhBSpnssZsaT a9MA== X-Gm-Message-State: ALoCoQmho55LNKRgUmIFvj60tw5XbgLJxQmnEquQtinkugvl3JxPuRxwktFbg9y8jBvr+M+1IxxO X-Received: by 10.180.106.197 with SMTP id gw5mr737678wib.1.1412425277573; Sat, 04 Oct 2014 05:21:17 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.180.85.73 with SMTP id f9ls331612wiz.14.canary; Sat, 04 Oct 2014 05:21:16 -0700 (PDT) X-Received: by 10.180.21.227 with SMTP id y3mr5441306wie.54.1412425276015; Sat, 04 Oct 2014 05:21:16 -0700 (PDT) Original-Received: from mail-wi0-x231.google.com (mail-wi0-x231.google.com [2a00:1450:400c:c05::231]) by mx.google.com with ESMTPS id mw7si4891109wic.87.2014.10.04.05.21.15 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Sat, 04 Oct 2014 05:21:16 -0700 (PDT) Received-SPF: pass (google.com: domain of daniel.kruegler@gmail.com designates 2a00:1450:400c:c05::231 as permitted sender) client-ip=2a00:1450:400c:c05::231; Original-Received: by mail-wi0-f177.google.com with SMTP id fb4so989856wid.4 for ; Sat, 04 Oct 2014 05:21:15 -0700 (PDT) X-Received: by 10.194.232.232 with SMTP id tr8mr14782990wjc.21.1412425275495; Sat, 04 Oct 2014 05:21:15 -0700 (PDT) Original-Received: by 10.216.187.4 with HTTP; Sat, 4 Oct 2014 05:21:15 -0700 (PDT) In-Reply-To: <8808df5e-62c4-459d-acd9-00e63adb9476@isocpp.org> X-Original-Sender: daniel.kruegler@gmail.com X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of daniel.kruegler@gmail.com designates 2a00:1450:400c:c05::231 as permitted sender) smtp.mail=daniel.kruegler@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:13657 Archived-At: 2014-10-01 10:00 GMT+02:00 Jeaye Wilkerson : > Folks, > > The stdlib could use a few new function templates to aid in creating generic > interfaces. With C++11, we were given std::begin to account for the fact > that C-style arrays are valid containers. I propose we add a very similar > set of functions of accessing the size of containers, including C-style > arrays. The interface is as follows: > > template > > auto size(T &c); > template > auto size(T const &c); > template > std::size_t constexpr size(T (&arr)[N]); > > A working implementation and some example code is included here: > http://coliru.stacked-crooked.com/a/a321818e19f0efae > > The two main benefits of this addition are as follows: > > Support for C-style arrays in generic implementations; this also makes the > std::xxx_n series more compatible with C-style arrays > Allowance of user-provided fully specialized versions of std::size for > custom types > > An example of 2 being: http://coliru.stacked-crooked.com/a/12c71f9970e37463 Have you looked at the existing proposal: http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2014/n4017.htm and if so what is the difference of your proposal? I should add that for the upcoming mailing deadline a revision of this proposal has already been submitted, so this is ongoing work. - Daniel -- --- 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/. .