220 13625 article Path: news.gmane.org!not-for-mail From: Tony V E Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: The view concept Date: Fri, 3 Oct 2014 13:44:01 -0400 Lines: 141 Approved: news@gmane.org Message-ID: References: <428c47bd-67f2-47d1-98c0-e5ca85698076@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: multipart/alternative; boundary=089e0160bf984447ba0504884718 X-Trace: ger.gmane.org 1412358253 11053 80.91.229.3 (3 Oct 2014 17:44:13 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Fri, 3 Oct 2014 17:44:13 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBCUZ5QWKNQIOFQF3UECRUBAXFKYDI@isocpp.org Fri Oct 03 19:44:05 2014 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-la0-f71.google.com ([209.85.215.71]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1Xa6tf-0000JF-OT for gclcip-std-proposals@m.gmane.org; Fri, 03 Oct 2014 19:44:03 +0200 Original-Received: by mail-la0-f71.google.com with SMTP id gi9sf986827lab.6 for ; Fri, 03 Oct 2014 10:44:03 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:in-reply-to:references:date :message-id:subject:from:to:x-original-sender :x-original-authentication-results:reply-to:precedence:mailing-list :list-id:list-post:list-help:list-archive:list-subscribe :list-unsubscribe:content-type; bh=gwHCoX2X/BD16+vEtDIbuiTJLG1NGc/6TUK+j9lWvuE=; b=KBSeERaMSFPKUcIYSFo6Zn086KXzvAlA/w81Aes71J5fgAhvVCvoYstZ0UvO0pNxOv 0p2c56ksrNXbqfjm+eyhibD7SM27dImUvbmsgTlgEqu8MJyxtBxE/agzc4eKJqQyqn2K m9aiKvqKTheLyOvB9EjyW5IyOhJ8xX5ECzNlmrSeD86j5g7iZBI+BFfn0dI90e9WfBX9 OurocNdeqJzH/iY8SbzTjwM2PwLWTXpYbqxy6MThuPNnawv86quLx3x+HPGDT7pnAYgh EkOZeElhWXC2g1HbiIMblrdIjgTGImwduTatRVEzX6LyiaNMNNp261U5p4RJNPcPo+/+ QHKQ== X-Gm-Message-State: ALoCoQnV9o1GNIrdn8t8drKNQIepfDS+ZXdzNm50u+O9ReWC3bMyRs9tJ5L3AGUfJE7Ss5PFWgMo X-Received: by 10.152.2.97 with SMTP id 1mr1233877lat.6.1412358243513; Fri, 03 Oct 2014 10:44:03 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.152.224.161 with SMTP id rd1ls387062lac.95.gmail; Fri, 03 Oct 2014 10:44:01 -0700 (PDT) X-Received: by 10.152.26.133 with SMTP id l5mr7856449lag.4.1412358241786; Fri, 03 Oct 2014 10:44:01 -0700 (PDT) Original-Received: from mail-lb0-x22c.google.com (mail-lb0-x22c.google.com [2a00:1450:4010:c04::22c]) by mx.google.com with ESMTPS id db6si12396668lad.9.2014.10.03.10.44.01 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Fri, 03 Oct 2014 10:44:01 -0700 (PDT) Received-SPF: pass (google.com: domain of tvaneerd@gmail.com designates 2a00:1450:4010:c04::22c as permitted sender) client-ip=2a00:1450:4010:c04::22c; Original-Received: by mail-lb0-f172.google.com with SMTP id b6so1453710lbj.3 for ; Fri, 03 Oct 2014 10:44:01 -0700 (PDT) X-Received: by 10.152.23.69 with SMTP id k5mr7646605laf.70.1412358241272; Fri, 03 Oct 2014 10:44:01 -0700 (PDT) Original-Received: by 10.112.75.199 with HTTP; Fri, 3 Oct 2014 10:44:01 -0700 (PDT) In-Reply-To: X-Original-Sender: tvaneerd@gmail.com X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of tvaneerd@gmail.com designates 2a00:1450:4010:c04::22c as permitted sender) smtp.mail=tvaneerd@gmail.com; dkim=pass header.i=@gmail.com; dmarc=pass (p=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:13625 Archived-At: --089e0160bf984447ba0504884718 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On Fri, Oct 3, 2014 at 1:25 PM, Matthew Fioravante wrote: > > > On Friday, October 3, 2014 12:54:14 PM UTC-4, Tony V E wrote: >> >> >> >> On Fri, Oct 3, 2014 at 9:17 AM, Klaim - Jo=C3=ABl Lamotte >> wrote: >> >>> I think that the most important question to answer is: what would be th= e >>> difference between a range and a view?=E2=80=8B >>> >> >> One major likely difference is that range =3D=3D will probably be 'shall= ow'. >> Deep-compare will probably be a function. >> > > I suppose the difference is that a range is a subset of a container, wher= e > as a view is a container itself, that is a non-owning container. In this > sense a view is not actually a range at all but you can create a range ov= er > a view for generic algorithm processing. You can also create a view from = a > range. > > Since view is a container, operator=3D=3D is deep because its operating o= n the > container contents. However view is a non-owning container, so operator= =3D > reassigns it to a new owner. We should have some way to do shallow compar= e > and deep copy for a view. > > >> >> In general, I think a 'view' is this name we use where we'd like to use >> range, but know that we haven't solidified what we mean by range yet, so= we >> are punting and going with 'view' for now. >> >> Also a view is a less-generic range. ie string_view has more than just >> range features, it also copies over all the functions from string. >> > > I think we should not call a view a range at all but a kind of container. > > Of course we are still arguing whether a container is a range... The biggest issue, in my mind, is that, IIUC, both Range and Container are Regular. View is not. ie View is a mix of deep and shallow, whereas both Range and Container are consistent in their deep/shallow-ness. Tony --=20 ---=20 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 e= mail 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-proposa= ls/. --089e0160bf984447ba0504884718 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable


On Fri, Oct 3, 2014 at 1:25 PM, Matthew Fioravante &l= t;fmatthew5876@= gmail.com> wrote:


On Friday, October 3, 2014 12:54:14 PM UTC-4, Tony V E wro= te:


On Fri, Oct 3, 2014 at 9:17 AM, K= laim - Jo=C3=ABl Lamotte <mjk...@gmail.com><= /span> wrote:
I think that the most important question to answer is: what would = be the difference between a range and a view?=E2=80=8B

One major likely difference is that range =3D=3D wil= l probably be 'shallow'.=C2=A0 Deep-compare will probably be a func= tion.

I suppo= se the difference is that a range is a subset of a container, where as a vi= ew is a container itself, that is a non-owning container. In this sense a v= iew is not actually a range at all but you can create a range over a view f= or generic algorithm processing. You can also create a view from a range.
Since view is a container, operator=3D=3D is deep because its operati= ng on the container contents. However view is a non-owning container, so op= erator=3D reassigns it to a new owner. We should have some way to do shallo= w compare and deep copy for a view.
=C2=A0
= =C2=A0
In general, I think a 'view' is this name we u= se where we'd like to use range, but know that we haven't solidifie= d what we mean by range yet, so we are punting and going with 'view'= ; for now.

Also a view is a less-generic range.=C2= =A0 ie string_view has more than just range features, it also copies over a= ll the functions from string.
=
I think we should not call a view a range at all but a kind of containe= r.
=C2=A0

Of course we a= re still arguing whether a container is a range...

The bi= ggest issue, in my mind, is that, IIUC, both Range and Container are Regula= r.=C2=A0 View is not. ie View is a mix of deep and shallow, whereas both Ra= nge and Container are consistent in their deep/shallow-ness.

Tony


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