220 33193 article Path: news.gmane.org!.POSTED!not-for-mail From: Dan Raviv Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Re: [idea for proposal] Adding std::shift to Date: Thu, 13 Jul 2017 00:14:38 +0300 Lines: 127 Approved: news@gmane.org Message-ID: References: <48819b6e-f08d-46b8-bc88-08d3640509a1@isocpp.org> <5666b7ac-b35e-4e9c-90ce-43a246b95f1a@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: multipart/alternative; boundary="001a1137cfe8fe0c8c0554254ee3" X-Trace: blaine.gmane.org 1499894109 25368 195.159.176.226 (12 Jul 2017 21:15:09 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Wed, 12 Jul 2017 21:15:09 +0000 (UTC) Cc: jmckesson@gmail.com, "dan@soundradix.com" To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBC5YJREBWAGRBVFCTLFQKGQEMLM2I5I@isocpp.org Wed Jul 12 23:15:04 2017 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-yb0-f199.google.com ([209.85.213.199]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1dVOyH-0005sr-MN for gclcip-std-proposals@m.gmane.org; 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[2607:f8b0:4003:c06::234]) by mx.google.com with ESMTPS id 131si2530705oii.143.2017.07.12.14.14.59 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 12 Jul 2017 14:14:59 -0700 (PDT) Received-SPF: pass (google.com: domain of dan.raviv@gmail.com designates 2607:f8b0:4003:c06::234 as permitted sender) client-ip=2607:f8b0:4003:c06::234; Original-Received: by mail-oi0-x234.google.com with SMTP id l130so30748935oib.1 for ; Wed, 12 Jul 2017 14:14:59 -0700 (PDT) X-Received: by 10.202.0.65 with SMTP id 62mr449469oia.86.1499894099345; Wed, 12 Jul 2017 14:14:59 -0700 (PDT) Original-Received: by 10.74.71.207 with HTTP; Wed, 12 Jul 2017 14:14:38 -0700 (PDT) In-Reply-To: X-Original-Sender: dan.raviv@gmail.com X-Original-Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.b=uJKASWKF; spf=pass (google.com: domain of dan.raviv@gmail.com designates 2607:f8b0:4003:c06::234 as permitted sender) smtp.mailfrom=dan.raviv@gmail.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=gmail.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:33193 Archived-At: --001a1137cfe8fe0c8c0554254ee3 Content-Type: text/plain; charset="UTF-8" I guess I shouldn't have consented to use the term 'logical' shift which Alexander used, I was just mirroring his term, but I see it just resulted in confusion. I'm discussing a shift of elements inside a generic container. It isn't 'logical' in any numeric sense. Implementing a logical shift (say for vector), which would handle positive and negative numbers correctly, is out of the scope for this proposal idea, I think. On Wed, Jul 12, 2017 at 10:51 PM, Nicol Bolas wrote: > On Wednesday, July 12, 2017 at 3:11:27 PM UTC-4, Dan Raviv wrote: >> >> Indeed, circular shift is just std::rotate. >> >> For the 'logical' shift, I was thinking leaving them in the moved-from >> state. Filling them with some value would both 1) have a cost 2) not >> necessarily be desired. >> > > But logical bitshifts do fill in a specific, well-defined value. So if > this is going to be separate from `move[_backward]`, then it ought to have > the behavior a user would expect. > > So I'm for the same behavior as the equivalent std::move[_backward], at >> least by default. >> > >> It is possible to add an optional fill-in value parameter, if that's >> something that would be deemed useful enough. >> > > -- > 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. > To view this discussion on the web visit https://groups.google.com/a/ > isocpp.org/d/msgid/std-proposals/df32b9a3-9215-4517- > 9bba-ba42654c55ee%40isocpp.org > > . > -- 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. To view this discussion on the web visit https://groups.google.com/a/isocpp.org/d/msgid/std-proposals/CADw4SdTSRXazyZUMrD_g%2BzS5HBLWPELDUzHjfEgZNd_AcC6_YA%40mail.gmail.com. --001a1137cfe8fe0c8c0554254ee3 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
I guess I shouldn't have consented to use the ter= m 'logical' shift which Alexander used, I was just mirroring his te= rm, but I see it just resulted in confusion.
I'm discussing a= shift of elements inside a generic container. It isn't 'logical= 9; in any numeric sense.

Implementing a logical sh= ift (say for vector<bool>), which would handle positive and negative = numbers correctly, is out of the scope for this proposal idea, I think.



On Wed, Jul 12, 2017 at 10:51 PM, Nicol Bolas <jmck= esson@gmail.com> wrote:
On Wednesday, July 12, 2017 at 3:11:27 PM UT= C-4, Dan Raviv wrote:
Indeed, circular shift is just std::rotate.

For the &= #39;logical' shift, =C2=A0I was thinking leaving them in the moved-from= state. Filling them with some value would both 1) have a cost 2) not neces= sarily be desired.

But logical bits= hifts do fill in a specific, well-defined value. So if this is going to be = separate from `move[_backward]`, then it ought to have the behavior a user = would expect.

So I'm for the same behavior as the equi= valent std::move[_backward], at least by default.
<= div>
It is possible to add an optional fill-in value parameter, if t= hat's something that would be deemed useful enough.

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