220 13651 <8808df5e-62c4-459d-acd9-00e63adb9476@isocpp.org> article Path: news.gmane.org!not-for-mail From: Jeaye Wilkerson Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Generic std::size, a la std::begin Date: Wed, 1 Oct 2014 01:00:55 -0700 (PDT) Lines: 136 Approved: news@gmane.org Message-ID: <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: multipart/alternative; boundary="----=_Part_1001_708181512.1412150455215" X-Trace: ger.gmane.org 1412406696 3751 80.91.229.3 (4 Oct 2014 07:11:36 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Sat, 4 Oct 2014 07:11:36 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBCT5TQUQ54HBBH53X2QQKGQE7P6EV3I@isocpp.org Sat Oct 04 09:11:30 2014 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-pd0-f200.google.com ([209.85.192.200]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1XaJV4-0005G9-Bq for gclcip-std-proposals@m.gmane.org; Sat, 04 Oct 2014 09:11:30 +0200 Original-Received: by mail-pd0-f200.google.com with SMTP id ft15sf5123192pdb.7 for ; Sat, 04 Oct 2014 00:11:28 -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:message-id:subject:mime-version :x-original-sender:reply-to:precedence:mailing-list:list-id :list-post:list-help:list-archive:list-subscribe:list-unsubscribe :content-type; bh=JdgDX3aWJdEi1noQ8rqMvV97X1aUZ9WyhTn6niunJuU=; b=iEHveYy768kiDS8QWRI9xmvT+xV0ytjbkSUcwoQ8LsShlMS09RkOVopW/a30YOBIac Ukftv8u97YwCN8SIkVnAB1QKA7uBGRIjv2A92ncnxgw5sn/a6IRs0owTjsv6XUd+K2b6 6V2UdHZm5Zs2SXpQpWIe70XzZbPKY5osRE7nirP7qPUhzOvJGJMrmu2JocS91Iocc9yI 6mGIPm9idIvylQu2H8+ua5AKC3lD6pi8EqbvUqFEDpoiya7oDsdPENW3f+T097wpPRwb rRpngfmNKc9XQ1l4rAm5nbsD1ewsdQnDw9gmMvBRnvqqKP1HL9BAUqb9wZ+qWMYv2fb8 fv7A== X-Gm-Message-State: ALoCoQnoZJ+HPYZwf+A09sBOoMQxHwtLDe3lu1PksQSSKOI7ZktRp7V+916zrxYDxc0AcA75H6mC X-Received: by 10.66.171.231 with SMTP id ax7mr5065304pac.29.1412406688198; Sat, 04 Oct 2014 00:11:28 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.50.20.132 with SMTP id n4ls1406372ige.10.canary; Sat, 04 Oct 2014 00:11:27 -0700 (PDT) X-Received: by 10.50.92.104 with SMTP id cl8mr2507271igb.1.1412406687602; Sat, 04 Oct 2014 00:11:27 -0700 (PDT) Original-Received: by 10.50.144.195 with SMTP id so3msigb; Wed, 1 Oct 2014 01:00:57 -0700 (PDT) X-Received: by 10.50.122.2 with SMTP id lo2mr203362igb.4.1412150457084; Wed, 01 Oct 2014 01:00:57 -0700 (PDT) X-Original-Sender: contact@jeaye.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:13651 Archived-At: ------=_Part_1001_708181512.1412150455215 Content-Type: text/plain; charset=UTF-8 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: 1. Support for C-style arrays in generic implementations; this also makes the std::xxx_n series more compatible with C-style arrays 2. 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 Regards, Jeaye -- --- 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/. ------=_Part_1001_708181512.1412150455215 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
Folks,

The stdlib could use a few new function temp= lates 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 con= tainers, including C-style arrays. The interface is as follows:

template<= span style=3D"color: #000;" class=3D"styled-by-prettify"> <typename T>
auto size(T &c);template <ty=
pename T><=
span style=3D"color: #000;" class=3D"styled-by-prettify">
a=
uto size(T const &c);
template <typename T, std::size_t N>
std<=
span style=3D"color: #660;" class=3D"styled-by-prettify">::size_t constexpr size(T (&arr)[N]);=

A working implementation and some examp= le code is included here: http://coliru.stacked-crooked.com/a/a321818e19f0efae
The two main benefits of this addition are as follows:
  1. Supp= ort for C-style arrays in generic implementations; this also makes the std:= :xxx_n series more compatible with C-style arrays
  2. Allowance of user= -provided fully specialized versions of std::size for custom types

    3. An example of 2 being: http://coliru.stacked-crooked.com/a/12c71f9970e37463

    Regards,
    Jeaye

    --

    ---
    You received this message because you are subscribed to the Google Groups &= quot;ISO C++ Standard - Future Proposals" group.
    To unsubscribe from this group and stop receiving emails from it, send an e= mail to std-proposa= ls+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/<= /a>.
    ------=_Part_1001_708181512.1412150455215-- .