220 29882 article Path: news.gmane.org!.POSTED!not-for-mail From: =?UTF-8?Q?Micha=C5=82_Dominiak?= Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: New smart pointer: CopyConstructible and CopyAssignable flavor of unique_ptr Date: Sat, 17 Dec 2016 18:16:02 +0000 Lines: 136 Approved: news@gmane.org Message-ID: References: <67a9e9ed-8748-4098-a43b-33598b516464@isocpp.org> <20161217141109.GA22645@manuel-ThinkPad-L440.localdomain> <3df7e8eb-01a0-7804-f476-504b5a25a9fe@gmail.com> <20161217170428.GA10214@manuel-ThinkPad-L440.localdomain> <20161217171633.4919375.58072.21574@gmail.com> <15884364-3238-41c7-bc5a-aa5595a64ade@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: multipart/alternative; boundary=94eb2c0b6858864dae0543deae3c X-Trace: blaine.gmane.org 1481998577 7972 195.159.176.226 (17 Dec 2016 18:16:17 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Sat, 17 Dec 2016 18:16:17 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBCA6D5ULVYBRB3UB23BAKGQEGMDX3JY@isocpp.org Sat Dec 17 19:16:11 2016 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-qt0-f197.google.com ([209.85.216.197]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1cIJWk-0000ho-Dv for gclcip-std-proposals@m.gmane.org; Sat, 17 Dec 2016 19:16:10 +0100 Original-Received: by mail-qt0-f197.google.com with SMTP id x26sf80248083qtb.6 for ; Sat, 17 Dec 2016 10:16:15 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=isocpp-org.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :x-original-sender:x-original-authentication-results:reply-to :precedence:mailing-list:list-id:x-spam-checked-in-group:list-post :list-help:list-archive:list-subscribe:list-unsubscribe; bh=Trz+N3pMOIEusB7qyHJdcEiC7wKmF/mb3N8PaGFtya0=; b=dDWsduOP2sFB6BIrrzz6e0ZL0T9S0uM6Bxx3/nG6wbhuiLIsjWUlztg9c8TAe6VfYf cEygmNed7sLc+gc2t6hTxNTtE7sH0ot/fbU+bhU0f9p3zNhW8LyVELDgA/8DKqVs0UsQ FVDf8L5oUxIstyOPJThGg9lGYmGvTU5iPTHk6A8JgvUZotyom/CiS1skLhI7UOxcTXeO ncZ493J9maiywEqeY2VchxMeOdgCeN+aEHm8lznqmbFmx7CT4j/PUUQpoLjzMFhBoMMQ 2ShF7+CWK+0vy8Wtn/aW6TPaRUB2dcKA68+nKWMiqIpMYo6k+1TBNFzhIcDge/bF716+ I/UQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:x-original-sender :x-original-authentication-results:reply-to:precedence:mailing-list :list-id:x-spam-checked-in-group:list-post:list-help:list-archive :list-subscribe:list-unsubscribe; bh=Trz+N3pMOIEusB7qyHJdcEiC7wKmF/mb3N8PaGFtya0=; b=c8vv8jFcY0qnWlHu9hKpQI5F4/D/upWp0SSrzPVLKZ+igD3aPEM3LMNtOhN5EXjSO/ gqIVD228Znw62AUEZbXEbIh6Vj6xgIZ5Pf3oIjCkxeZQBQdgpQRHr2FW/ZvlhwdJGOjM 0eVxDaXK1QbZRdv+Z11+U8xIhJTtFM+BtPVjdzKI95+lgRZOE2iTxk1SegmXDpTb3mLW gWJ1nJfXA1qUOIjU5XpTA1zsy38TBrnrQFAt88NvrBFpnth81c02zahB2qTPce3/cNQ6 yPf7iY+AifZywI+pAVXqcazv6P+iRvxmIWs81CJmTLKz2ex9wlxEkIq5Hf1z789FuOam kaHQ== X-Gm-Message-State: AIkVDXLjlpbYg2zgB4qw9Py0SdtaQpmZCTKklZHXjGXhEkUp/2OoLdCQQyKA50Ika5y7dA== X-Received: by 10.200.43.136 with SMTP id m8mr1959373qtm.3.1481998574645; Sat, 17 Dec 2016 10:16:14 -0800 (PST) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.157.45.195 with SMTP id g61ls10458831otb.37.gmail; Sat, 17 Dec 2016 10:16:13 -0800 (PST) X-Received: by 10.159.32.8 with SMTP id 8mr6010691uam.129.1481998573881; Sat, 17 Dec 2016 10:16:13 -0800 (PST) Original-Received: from mail-ua0-x229.google.com (mail-ua0-x229.google.com. [2607:f8b0:400c:c08::229]) by mx.google.com with ESMTPS id 61si3393423uay.227.2016.12.17.10.16.13 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sat, 17 Dec 2016 10:16:13 -0800 (PST) Received-SPF: neutral (google.com: 2607:f8b0:400c:c08::229 is neither permitted nor denied by best guess record for domain of admin@griwes.info) client-ip=2607:f8b0:400c:c08::229; Original-Received: by mail-ua0-x229.google.com with SMTP id 12so67493068uas.2 for ; Sat, 17 Dec 2016 10:16:13 -0800 (PST) X-Received: by 10.159.41.34 with SMTP id t31mr1221346uat.153.1481998573386; Sat, 17 Dec 2016 10:16:13 -0800 (PST) In-Reply-To: X-Original-Sender: griwes@griwes.info X-Original-Authentication-Results: mx.google.com; dkim=pass header.i=@griwes-info.20150623.gappssmtp.com; spf=neutral (google.com: 2607:f8b0:400c:c08::229 is neither permitted nor denied by best guess record for domain of admin@griwes.info) smtp.mailfrom=admin@griwes.info 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:29882 Archived-At: --94eb2c0b6858864dae0543deae3c Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable So you're saying that the standard should not contain tools targeted at experts? (Just a note: it already does.) On Sat, Dec 17, 2016 at 7:14 PM Jonathan M=C3=BCller < jonathanmueller.dev@gmail.com> wrote: > On Dec 17, 2016 7:04 PM, "Nicol Bolas" wrote: > > > > I don't think "might be harmful" is a good enough reason to not have th= e > type. > > I think it's a very compelling reason. I rather have types that can be > used without thinking, because misuse is a compiler error. > > > After all, such copying behavior won't break most standard library > types. `vector` will work as expected, as will `any`, > `optional`, `variant`, and so forth. > > All of these type work without copy constructing. The only reason you'd > need copy constructing there is if you'd need to insert a copy or copy th= e > container. The first one is very easy, just call clone, the second requir= es > a for loop. > > > I think it's important to understand that `clone_ptr` is a solution to = a > very specific problem, one that isn't exactly common. You shouldn't see a > huge number of these pointers lying around. > > Yeah, and that's why I can't really see a compelling use case for them. > > -- > 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/CAEddoJa4V_U= Fj7xcNwR_YNqCfbNtEMbXZgsYDyXCx%3DM51E2xdQ%40mail.gmail.com > > . > --=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. To view this discussion on the web visit https://groups.google.com/a/isocpp= ..org/d/msgid/std-proposals/CAPCFJdRj%2BqTfY2oBKk3nOy41Sd-EBqv5t-2Vr1T2t%3D6= -Nf53yg%40mail.gmail.com. --94eb2c0b6858864dae0543deae3c Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
So you're saying that the standard should not contain = tools targeted at experts? (Just a note: it already does.)

On Sat, Dec 17, 2016 at 7:14 PM Jonath= an M=C3=BCller <jonatha= nmueller.dev@gmail.com> wrote:

On Dec 17, 2016 7:04 PM, "Nicol = Bolas" <jmckesson@gmail.com> wrote:
>
> I don't think "might be harmful" is a good enough reason= to not have the type.

I think it's a very compelling reaso= n. I rather have types that can be used without thinking, because misuse is= a compiler error.

> After all, such copying behavior wo= n't break most standard library types. `vector<clone_ptr>` will w= ork as expected, as will `any`, `optional<clone_ptr>`, `variant<cl= one_ptr>`, and so forth.

All of these type work without copy cons= tructing. The only reason you'd need copy constructing there is if you&= #39;d need to insert a copy or copy the container. The first one is very ea= sy, just call clone, the second requires a for loop.

> I think it's important to under= stand that `clone_ptr` is a solution to a very specific problem, one that i= sn't exactly common. You shouldn't see a huge number of these point= ers lying around.

Yeah, and that's why I can't rea= lly see a compelling use case for them.

--
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-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/CAEddoJa4V_UFj7xcNwR_YNqCfbNtEMbXZgsYDyXCx%3DM51= E2xdQ%40mail.gmail.com.

--
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.
To view this discussion on the web visit https://groups.google.com/a/isocpp.org/d/msgid/std-proposals/CAPCFJdRj%2Bq= TfY2oBKk3nOy41Sd-EBqv5t-2Vr1T2t%3D6-Nf53yg%40mail.gmail.com.
--94eb2c0b6858864dae0543deae3c-- .