220 21313 article Path: news.gmane.org!not-for-mail From: Vlad from Moscow Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Conversion from lvalue to rvalue Date: Mon, 5 Oct 2015 13:24:38 -0700 (PDT) Lines: 90 Approved: news@gmane.org Message-ID: Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_Part_579_437436720.1444076678851" X-Trace: ger.gmane.org 1444076683 354 80.91.229.3 (5 Oct 2015 20:24:43 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Mon, 5 Oct 2015 20:24:43 +0000 (UTC) To: ISO C++ Standard - Future Proposals Original-X-From: std-proposals+bncBCXLLRHD7IDRBCFZZOYAKGQEFVMFR2A@isocpp.org Mon Oct 05 22:24:42 2015 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-oi0-f72.google.com ([209.85.218.72]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1ZjCJN-0003BD-L4 for gclcip-std-proposals@m.gmane.org; Mon, 05 Oct 2015 22:24:41 +0200 Original-Received: by oibi136 with SMTP id i136sf294297792oib.3 for ; Mon, 05 Oct 2015 13:24:40 -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 :content-type:x-original-sender:reply-to:precedence:mailing-list :list-id:x-spam-checked-in-group:list-post:list-help:list-archive :list-subscribe:list-unsubscribe; bh=4TaArQ1J/mN3tvki/ZeJScW4gczU+RXuoaE5GAkjId8=; b=iGV6ZNQ8ONBh+q8cMo8MYUA+MtiPldXkKq5x6gYbmEhE//7sZIwTewxKiLqOZZxs3T UwVKjUVkewnZTDfc8cwEoyXXqkeblKIYInk2YTdeVAlGC6PesvcYHn/NIgoAdUQSyfvm p04Sd5+vOpr7t3+S20CACYnWmhg6Uq0oq7cdRPBUhn7PAlL0tbV9sJFdPP2Ytz8Epy0l p3XGiCnjaPmNizApN//X2WVxjT8uHBWXZa9sNkThyGeNgGbkNDl3Ivey3vnFhYV4ROZL V6eARd3HqaShLuZyIw1UpPQJwBEW7ILa2+cA523ib9Z1Ll32Zuj9dTB66AWbCZoSgc76 mlIw== X-Gm-Message-State: ALoCoQnjwGOjGyZhHylP7gN+TYyiP4wrqEWHeQWPJML/n//ISuck7NODIcmasHeAOgjAj+ChkpzN X-Received: by 10.182.24.9 with SMTP id q9mr29198866obf.13.1444076680847; Mon, 05 Oct 2015 13:24:40 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.50.111.79 with SMTP id ig15ls1312440igb.10.gmail; Mon, 05 Oct 2015 13:24:39 -0700 (PDT) X-Received: by 10.50.131.164 with SMTP id on4mr154991igb.8.1444076679886; Mon, 05 Oct 2015 13:24:39 -0700 (PDT) X-Original-Sender: vlad.moscow@mail.ru Precedence: list Mailing-list: list std-proposals@isocpp.org; contact std-proposals+owners@isocpp.org List-ID: X-Spam-Checked-In-Group: std-proposals@isocpp.org 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:21313 Archived-At: ------=_Part_579_437436720.1444076678851 Content-Type: multipart/alternative; boundary="----=_Part_580_478032097.1444076678851" ------=_Part_580_478032097.1444076678851 Content-Type: text/plain; charset=UTF-8 One of methods to convert lvalue to rvalue is to use the functional of explicit conversion. Compare these two examples //... int main() { { int a = 10; int b = 5; std::tie( a, b ) = std::minmax( a, b ); std::cout << "a = " << a << ", b = " << b << std::endl; } { int a = 10; int b = 5; std::tie( a, b ) = std::minmax( int { a }, int { b } ); std::cout << "a = " << a << ", b = " << b << std::endl; } } The out put correspondingly is a = 5, b = 5 a = 5, b = 10 I am suggesting to use the following general syntax std::tie( a, b ) = std::minmax( auto( a ), auto( b ) ); -- --- 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_580_478032097.1444076678851 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
One of methods to convert=C2=A0lvalue to rvalue is to= use the functional of explicit conversion.

Compar= e these two examples

//...

int main()
{
{
=C2=A0=C2=A0=C2=A0 int a =3D 10;
=C2=A0=C2=A0= =C2=A0 int b =3D 5;
=C2=A0=C2=A0=C2=A0
=C2=A0=C2=A0=C2=A0 std::tie( = a, b ) =3D std::minmax( a, b );
=C2=A0=C2=A0=C2=A0 std::cout << &q= uot;a =3D " << a << ", b =3D " << b <&l= t; std::endl;
}
{
=C2=A0=C2=A0=C2=A0 int a =3D 10;
=C2=A0=C2=A0= =C2=A0 int b =3D 5;
=C2=A0=C2=A0=C2=A0
=C2=A0=C2=A0=C2=A0 std::tie( = a, b ) =3D std::minmax( int { a }, int { b } );
=C2=A0=C2=A0=C2=A0 std::= cout << "a =3D " << a << ", b =3D " &= lt;< b << std::endl;
}
}

The out=C2= =A0put correspondingly is

a =3D 5, b =3D 5
a = =3D 5, b =3D 10

I am suggesting to use the followi= ng general syntax

=C2=A0=C2=A0=C2=A0 std::tie( a, = b ) =3D std::minmax(=C2=A0auto( a ),=C2=A0auto( b=C2=A0) );

--

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