220 21342 <0a839ad1-1a3c-4323-a20c-3cd910ec08f4@isocpp.org> article Path: news.gmane.org!not-for-mail From: Vlad from Moscow Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Conversion from lvalue to rvalue Date: Tue, 6 Oct 2015 03:56:04 -0700 (PDT) Lines: 128 Approved: news@gmane.org Message-ID: <0a839ad1-1a3c-4323-a20c-3cd910ec08f4@isocpp.org> References: Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_Part_380_1729232834.1444128964460" X-Trace: ger.gmane.org 1444128971 10863 80.91.229.3 (6 Oct 2015 10:56:11 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Tue, 6 Oct 2015 10:56:11 +0000 (UTC) To: ISO C++ Standard - Future Proposals Original-X-From: std-proposals+bncBCXLLRHD7IDRBRORZ2YAKGQE2PF6RGY@isocpp.org Tue Oct 06 12:56:10 2015 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-yk0-f198.google.com ([209.85.160.198]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1ZjPuh-0000iC-C4 for gclcip-std-proposals@m.gmane.org; Tue, 06 Oct 2015 12:56:07 +0200 Original-Received: by ykdg206 with SMTP id g206sf276003268ykd.1 for ; Tue, 06 Oct 2015 03:56:06 -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:in-reply-to:references :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=AddaPCLnX8jDToTJnO/Bi8aQGhlsJ3TE1AOgwK5VBNE=; b=KOE19nBhVzTWgKV1HrGwmIr8b62y9slQ2Ynpm+HzYK+tIcKbLkC1kHd/owHxPm5EtJ LZe8hpLiPfgmZ6XOMblJWn541Qa1SL3RhUaS5pWN/lvf6w+6P0oPjghQzz4eoy1JU+Ss PpYnGJjbrOfZZl06FqHLK/G886DyPRR5iaGSM6JUT1++Pu2i+PwC4uwOCke+wXqQpyk+ EaeqaRgnjr3L+4BvOIQbvz3O3UBtpd11Y4J3jQC+ZS/WL0TT7CgmuQJ1A7dkbyd3aZvl g4Xi0dQ8XS1XreUzPUsP+P1ZZefxhR9Vfx7GlKR72TepSUa7dfkFk4L3uuaYXVAzeXLz +dDg== X-Gm-Message-State: ALoCoQngk6wEG/MMx1MhLSbqBYolDVY3E6m+OCndiHEYR/59kAwHNVbCiGQiF7PGhruBh4JNcT3E X-Received: by 10.140.237.202 with SMTP id i193mr30391396qhc.10.1444128966351; Tue, 06 Oct 2015 03:56:06 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.107.132.164 with SMTP id o36ls1873103ioi.64.gmail; Tue, 06 Oct 2015 03:56:05 -0700 (PDT) X-Received: by 10.50.114.36 with SMTP id jd4mr185767igb.6.1444128965417; Tue, 06 Oct 2015 03:56:05 -0700 (PDT) In-Reply-To: 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:21342 Archived-At: ------=_Part_380_1729232834.1444128964460 Content-Type: multipart/alternative; boundary="----=_Part_381_1227441326.1444128964470" ------=_Part_381_1227441326.1444128964470 Content-Type: text/plain; charset=UTF-8 On Monday, October 5, 2015 at 11:24:39 PM UTC+3, Vlad from Moscow wrote: > > 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 ) ); > > A simplified example that demonstrates the idea #include void f( int &&x ) { std::cout << "f( int &&( " << x << " ) )\n"; } void f( int &x ) { std::cout << "f( int &( " << x << " ) )\n"; } int main() { int x = 3; f( x ); f( 3 ); } So in the code above I want to substitute the call f( 3 ) for f( auto( x ) ); -- --- 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_381_1227441326.1444128964470 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
On Monday, October 5, 2015 at 11:24:39 PM UTC+3, Vlad from Moscow wrote= :
One of methods to conve= rt=C2=A0lvalue to rvalue is to use the functional of explicit conversion.

Compare 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 << "a =3D " << a << ",= b =3D " << b << 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 " << b << std::endl;
}
}

The out=C2=A0put correspondingly is

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

I a= m suggesting to use the following general syntax

= =C2=A0=C2=A0=C2=A0 std::tie( a, b ) =3D std::minmax(=C2=A0auto( a ),=C2=A0a= uto( b=C2=A0) );


A simp= lified example that demonstrates the idea

#include= <iostream>

void f( int &&x ) { std:= :cout << "f( int &&( " << x << " )= )\n"; }
void f(=C2=A0int &x ) { std::cout << "f(=C2= =A0int &( " << x << " ) )\n"; }
int main()
{
=C2=A0=C2=A0=C2=A0 int x =3D 3;

=C2=A0=C2=A0=C2=A0 f( x );
=C2=A0=C2=A0=C2=A0 f( 3 );<= br>}=C2=A0=C2=A0=C2=A0

So in the code above I= want to substitute the call f( 3 ) for

f( auto( x= ) );

=C2=A0

--

---
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>.
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