220 11016 article Path: news.gmane.org!not-for-mail From: Ville Voutilainen Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Re: Core Issue: deleted templates Date: Mon, 2 Jun 2014 15:37:36 +0300 Lines: 41 Approved: news@gmane.org Message-ID: References: Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-Trace: ger.gmane.org 1401712665 17774 80.91.229.3 (2 Jun 2014 12:37:45 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Mon, 2 Jun 2014 12:37:45 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBC5JHI7A7ALRBEHAWGOAKGQEFN2UPMQ@isocpp.org Mon Jun 02 14:37:38 2014 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-qa0-f70.google.com ([209.85.216.70]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1WrRUg-00034H-5X for gclcip-std-proposals@m.gmane.org; Mon, 02 Jun 2014 14:37:38 +0200 Original-Received: by mail-qa0-f70.google.com with SMTP id cm18sf8198551qab.5 for ; Mon, 02 Jun 2014 05:37:37 -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=NRC0dT+aPfJQkn2p2XpPdS86YmuY+c/fk81SAnOewGQ=; b=Ai1SPgz+bSGKyr588CNoBpTBHRZ5I3Hjjsn8aai/Mhj6E2iVV1BrtN2IgYHbSJ4ZvN d9Bxh5NfA+kDkIYngJC/+/nMzX8on6AlKJFAX6zpeN2syCWvOZztiUOp+UxWSEtmS+Lq 8m3Pd3OWjaqsxvQbcDxefmNwgLt/bpTGMm2grQJUpr1YoF3HAI9KAhNrE7vB6I7be6ek AHZhkfw9q3Kjsruir7/c1vv5TifTHnL80+LVHF0NmWRrbuiPJ/mwd9ZbL9yP6fb4wHeI 225MgrYEFvve1q3pq00CIYCw1Q53Hqcr1O3J10TO7SQjxD3Hzb3iahLC8sUtX5MnGUOy bWfw== X-Gm-Message-State: ALoCoQnWTU1fMA0jrvyfRM7zXVT2WY+ZKHr8iLw/NINLYBvftVKD6O0X+vGOTXNkW949kdquEkk6 X-Received: by 10.58.160.72 with SMTP id xi8mr2281962veb.15.1401712657203; Mon, 02 Jun 2014 05:37:37 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.140.84.239 with SMTP id l102ls1932314qgd.81.gmail; Mon, 02 Jun 2014 05:37:36 -0700 (PDT) X-Received: by 10.224.160.142 with SMTP id n14mr48839034qax.32.1401712656583; Mon, 02 Jun 2014 05:37:36 -0700 (PDT) Original-Received: from mail-qg0-x231.google.com (mail-qg0-x231.google.com [2607:f8b0:400d:c04::231]) by mx.google.com with ESMTPS id y5si17729362qab.8.2014.06.02.05.37.36 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Mon, 02 Jun 2014 05:37:36 -0700 (PDT) Received-SPF: pass (google.com: domain of ville.voutilainen@gmail.com designates 2607:f8b0:400d:c04::231 as permitted sender) client-ip=2607:f8b0:400d:c04::231; Original-Received: by mail-qg0-f49.google.com with SMTP id a108so10323236qge.22 for ; Mon, 02 Jun 2014 05:37:36 -0700 (PDT) X-Received: by 10.224.16.199 with SMTP id p7mr49298856qaa.76.1401712656327; Mon, 02 Jun 2014 05:37:36 -0700 (PDT) Original-Received: by 10.224.181.5 with HTTP; Mon, 2 Jun 2014 05:37:36 -0700 (PDT) In-Reply-To: X-Original-Sender: ville.voutilainen@gmail.com X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of ville.voutilainen@gmail.com designates 2607:f8b0:400d:c04::231 as permitted sender) smtp.mail=ville.voutilainen@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:11016 Archived-At: On 2 June 2014 15:21, Douglas Boffey wrote: > Comments, please. 1) For deprecating a class, we already have [[deprecated]] 2) I don't know what the paper means by an "unconditional static_assert", in template class X{static_assert(!sizeof(T), "the main template for X can't be used");}; template <> class X {}; the static_assert is not unconditional. The motivation is weak, and it doesn't provide exemplified comparisons of the design decisions, thus not explaining how this deletion support for classes and class templates is superior to existing facilities. I would certainly expect to see an example of a deleted class template with non-deleted specializations, and a non-deleted class template with some of the specializations deleted. The latter part is perhaps something that we can't currently do in a convenient fashion, but I can still do it with is_same, so that would still require motivation for this feature, since there are ways to achieve the same effect. Summa summarum, this proposal needs to explain a) *why* it's important to have a new specific feature for these things and b) *why* this feature is superior to what's currently available. In other words, "how is it better?" and "why does that even matter?". -- --- 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/. .