220 13652 <20141004004445.GA8207@lenovo> article Path: news.gmane.org!not-for-mail From: Jeaye Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Generic std::size, a la std::begin Date: Sat, 4 Oct 2014 08:44:46 +0800 Lines: 86 Approved: news@gmane.org Message-ID: <20141004004445.GA8207@lenovo> 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=UTF-8 Content-Transfer-Encoding: quoted-printable X-Trace: ger.gmane.org 1412408912 25498 80.91.229.3 (4 Oct 2014 07:48:32 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Sat, 4 Oct 2014 07:48:32 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBCT5TQUQ54HBBRGMX2QQKGQEKXOMJIA@isocpp.org Sat Oct 04 09:48:26 2014 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-yk0-f199.google.com ([209.85.160.199]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1XaK4k-0000sL-Kq for gclcip-std-proposals@m.gmane.org; Sat, 04 Oct 2014 09:48:22 +0200 Original-Received: by mail-yk0-f199.google.com with SMTP id 131sf3314607ykp.6 for ; Sat, 04 Oct 2014 00:48:21 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:date:from:to:subject:message-id:references :mime-version:in-reply-to:user-agent: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:content-disposition :content-transfer-encoding; bh=zHgXYc7PWgbhkqYRo/XVEWro2BkSQSLFxPD46Rl0Jw0=; b=AlssBU478sUmj+0jjQXOdDo32H3THyWXZlfguVIt/LXGgRLN5pW9pPX9BbPud39xPg orlpZ6Aixd00HA/0ssnetdMmh3SQyX3S9mnZon1JvP8TXCDp+s3DSTBrEDl2OYenMHmG 1V0JGZ8RBzKb1fkrsJ6XCrT/u7Rd3Zuw64zgX5jgJDiukQKmb78raFYNFdmfPcQVYaxO MYplTr89z3motDpcl5/DbvOszXriC40+IVAjGnWO82T96oSErQpKrr5JPdtQmAeEmyxl D6Cabwy882VDexAja1iwLTETMCnkU3bwQnudxj4jlUMn3z3Lu0V X-Gm-Message-State: ALoCoQmSX5v3TIyI4JYMI0SXOl65NyvTqLWG916Znf3FfLI++l7lRl18gl9S95Z3IMyrf8SqEDo7 X-Received: by 10.52.28.234 with SMTP id e10mr8609797vdh.1.1412408901330; Sat, 04 Oct 2014 00:48:21 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.50.164.169 with SMTP id yr9ls1423609igb.11.canary; Sat, 04 Oct 2014 00:48:20 -0700 (PDT) X-Received: by 10.66.191.230 with SMTP id hb6mr12090058pac.72.1412408900566; Sat, 04 Oct 2014 00:48:20 -0700 (PDT) Original-Received: from gproxy8-pub.mail.unifiedlayer.com (gproxy8-pub.mail.unifiedlayer.com. 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Not constexpr 2. Terribly verbose Regards, Jeaye On Wed, Oct 01, 2014 at 01:00:55AM -0700, Jeaye Wilkerson wrote: > Folks, >=20 > 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 fo= r > 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, includin= g > C-style arrays. The interface is as follows: >=20 > template >=20 > auto size(T &c); > template > auto size(T const &c); > template > std::size_t constexpr size(T (&arr)[N]); >=20 > A working implementation and some example code is included here: > [1]http://coliru.stacked-crooked.com/a/a321818e19f0efae >=20 > The two main benefits of this addition are as follows: >=20 > =C2=A01.=C2=A0Support for C-style arrays in generic implementations; t= his also makes > the std::xxx_n series more compatible with C-style arrays > =C2=A02.=C2=A0Allowance of user-provided fully specialized versions of= std::size for > custom types >=20 > An example of 2 being: > [2]http://coliru.stacked-crooked.com/a/12c71f9970e37463 >=20 > Regards, > Jeaye >=20 > -- >=20 > --- > You received this message because you are subscribed to a topic in the > Google Groups "ISO C++ Standard - Future Proposals" group. > To unsubscribe from this topic, visit > [3]https://groups.google.com/a/isocpp.org/d/topic/std-proposals/KyWbsV= meGgY/unsubscribe. > To unsubscribe from this group and all its topics, send an email to > [4]std-proposals+unsubscribe@isocpp.org. > To post to this group, send email to [5]std-proposals@isocpp.org. > Visit this group at > [6]http://groups.google.com/a/isocpp.org/group/std-proposals/. >=20 > References >=20 > Visible links > 1. http://coliru.stacked-crooked.com/a/a321818e19f0efae > 2. http://coliru.stacked-crooked.com/a/12c71f9970e37463 > 3. https://groups.google.com/a/isocpp.org/d/topic/std-proposals/KyWbsV= meGgY/unsubscribe > 4. mailto:std-proposals+unsubscribe@isocpp.org > 5. mailto:std-proposals@isocpp.org > 6. http://groups.google.com/a/isocpp.org/group/std-proposals/ --=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/. .