220 22643 <51173e9e-9b40-43a2-b8b2-832ea5895fb5@isocpp.org> article Path: news.gmane.org!not-for-mail From: Lingxi Li Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Post-assignment operator Date: Sat, 14 Nov 2015 10:16:11 -0800 (PST) Lines: 139 Approved: news@gmane.org Message-ID: <51173e9e-9b40-43a2-b8b2-832ea5895fb5@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_676_1162193704.1447524971092" X-Trace: ger.gmane.org 1447524988 20794 80.91.229.3 (14 Nov 2015 18:16:28 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Sat, 14 Nov 2015 18:16:28 +0000 (UTC) To: ISO C++ Standard - Future Proposals Original-X-From: std-proposals+bncBC27Z75TZMMBB3HUTWZAKGQEYE6CEHI@isocpp.org Sat Nov 14 19:16:13 2015 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-io0-f199.google.com ([209.85.223.199]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1ZxfMz-0007kL-6u for gclcip-std-proposals@m.gmane.org; Sat, 14 Nov 2015 19:16:13 +0100 Original-Received: by ioo197 with SMTP id 197sf167372979ioo.0 for ; Sat, 14 Nov 2015 10:16:12 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=isocpp_org.20150623.gappssmtp.com; s=20150623; h=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=FWifWLovRQdTv+yTwt0y1/fUhzDZDeFEYakIam6NfH4=; b=vdehItV58MjuXA+/qCZzMs8tVqgbR+/r8iSHCrGX1HrRr4Vj0c+o0G+mKnz6/cKcCj Nq4Drszh5w+uYgS7EzR5YBq9Z4HtndbWQ4UxFvJFUTk/P/+cXzq+RNJVedxwWmDHWxa9 UV/ceKX3MfCzLRyrcSiRySuFcl1FJ1jFHxwlUmSTG5fM93fnxURZMO//+4gXchWRHkSW /4cqJ2Wb8JQrAKAf1lqZQ4G0ZrUFFrz+Xn2cYp0z1jU6ZGqr9y/5PXY3r7JTcroiKR0H nj+hpbfiTeEMUV+zDw4za1ZDYyM1YqE1Z8ROUO4Ir44vIl2LY4aQYJs/lWSwILhx6CN5 R27A== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=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=FWifWLovRQdTv+yTwt0y1/fUhzDZDeFEYakIam6NfH4=; b=VxR5o4Fa7ROb0zkBLkLbIH6yq53h31f3vFPqC8nU4AosFJL/lie8HpoTko0xBVDBFE Nn4l0j7a2YygVI5GWSrUEYSJnS4idIOLJDVhzlM+R8m9XpDr6k4FHw2aeiNvEltoWEju va+pwEmnGu3+lXI3cVPmj9Ba6pMBNrEpoW2T7t3GzANaDnusalgT5ANE/eoHWXAHIGdb wBy0BT3I3rR1LsPVFFuA9wDRBIbl3sKYwaPhabwdGW2XvXGdSNTxv3dWWXQ3rpIIblc+ rGgwJW5P5QMqVTBlnq2h7AHNlCtiJjukW5O1NMc3CGf3TUUkYLMDPWANmg3PV28k8Yx+ cHqA== 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=FWifWLovRQdTv+yTwt0y1/fUhzDZDeFEYakIam6NfH4=; b=A25n4b8NzQ0dL1os/Y8cUHoJfUpZuGHavJTocbin5YNOUPdT83dwILJg/3Noy/2eeh 8T7Zi94bW1x4hSRZRi2Ku3kBrjmx38TpkFmlG9/KBlyCRHXt2RhCzuguMRfdqPmcM7kD ykk4zJUNXRe1+m0uNutUtDz2nLEfY5iS4KIplXkqkaI9gvUGTyrr/uG42XIINr+hp3d3 Dz2PeXkWoz8x1SUvcgk6RILIyQ49QZ45gkyLmvHBJJ9vSszq1tD2hVRyybsqFvNw7L3f utM+21Yxka2yhHc1WSMwTmytJ4shW4pLgwC9aaH3WTGY8I/5PJBtmgIalxp9T25DmHkQ jH3w== X-Gm-Message-State: ALoCoQmGXflqHvQpq8gPzOyFLSJdXz1T/Y73pFkI7b7X6HabzGYnMdiQKKbAFcQgRw5kMAoP3zdg X-Received: by 10.107.128.166 with SMTP id k38mr25190617ioi.34.1447524972502; Sat, 14 Nov 2015 10:16:12 -0800 (PST) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.50.114.102 with SMTP id jf6ls520452igb.5.gmail; Sat, 14 Nov 2015 10:16:11 -0800 (PST) X-Received: by 10.50.40.36 with SMTP id u4mr150086igk.5.1447524971819; Sat, 14 Nov 2015 10:16:11 -0800 (PST) In-Reply-To: X-Original-Sender: lilingxi.cs@gmail.com 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:22643 Archived-At: ------=_Part_676_1162193704.1447524971092 Content-Type: multipart/alternative; boundary="----=_Part_677_804193311.1447524971093" ------=_Part_677_804193311.1447524971093 Content-Type: text/plain; charset=UTF-8 I didn't know about this thing yet. But, yes, this will do it, though as a library feature. Thanks :) On Sunday, November 15, 2015 at 2:07:17 AM UTC+8, Jeffrey Yasskin wrote: > > Check out std::exchange(). > On Nov 14, 2015 9:32 AM, "Lingxi Li" > > wrote: > >> I frequently find code similar to the following: >> >> delete ptr; >> ptr = nullptr; >> close(fd); >> fd = -1; >> >> Why don't we just introduce a post-assignment operator that performs the >> assignment >> but returns the previous value of the left-hand-side, just like the >> post-increment/decrement >> operator? Denote such an operator by `.=`, the above code snippet could >> be simplied to >> >> delete ptr .= nullptr; >> close(fd .= -1); >> >> -- >> >> --- >> 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-proposal...@isocpp.org . >> To post to this group, send email to std-pr...@isocpp.org . >> Visit this group at >> http://groups.google.com/a/isocpp.org/group/std-proposals/. >> > -- --- 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_677_804193311.1447524971093 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
I didn't know about this thing yet. But, yes, this wil= l do it, though as a library feature. Thanks :)

On Sunday, November = 15, 2015 at 2:07:17 AM UTC+8, Jeffrey Yasskin wrote:

Check out std::exchange().

On Nov 14, 2015 9:32 AM, "Lingxi Li" &= lt;li= lin...@gmail.com> wrote:
I frequently find code similar to the follow= ing:

delete ptr;
ptr =3D nullptr;
close(fd);
fd =3D -1;

Why = don't we just introduce a post-assignment operator that performs the as= signment
but returns the previous value of the left-hand-side, just like= the post-increment/decrement
operator? Denote such an operator by `.=3D= `, the above code snippet could be simplied to

delete ptr .=3D nullptr;
close(fd .=3D -1);

--

---
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-proposal...@isocpp.org.
To post to this group, send email to std-pr...@isocpp.org.
Visit this group at http://groups.google.com/a/i= socpp.org/group/std-proposals/.

--

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