220 25007 <8922074a-fe00-4476-a8ef-8ba5840e1338@isocpp.org> article Path: news.gmane.org!not-for-mail From: "'Walt Karas' via ISO C++ Standard - Future Proposals" Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: "Components" template with implicitly defined partial specializations for all classes Date: Sun, 6 Mar 2016 15:26:22 -0800 (PST) Lines: 237 Approved: news@gmane.org Message-ID: <8922074a-fe00-4476-a8ef-8ba5840e1338@isocpp.org> References: <56D9E17F.2070202@wanadoo.fr> <2b0bcca0-0939-49f7-939b-4d688f8dfe34@isocpp.org> <324dbff9-84da-46f2-b2f3-3d9fe0cc2082@isocpp.org> <56DA88DF.90000@wanadoo.fr> <7e46c46d-2e18-4cec-92c1-4f4d7fbc786b@isocpp.org> <56DC58FC.9020009@wanadoo.fr> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_Part_2580_521731145.1457306782711" X-Trace: ger.gmane.org 1457306792 17410 80.91.229.3 (6 Mar 2016 23:26:32 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Sun, 6 Mar 2016 23:26:32 +0000 (UTC) To: ISO C++ Standard - Future Proposals Original-X-From: std-proposals+bncBDFLZXWOVYIBBH7Z6K3AKGQE5QJ7O7Y@isocpp.org Mon Mar 07 00:26:27 2016 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-ig0-f199.google.com ([209.85.213.199]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1aci49-0004hg-Mp for gclcip-std-proposals@m.gmane.org; Mon, 07 Mar 2016 00:26:26 +0100 Original-Received: by mail-ig0-f199.google.com with SMTP id dp10sf88859612igc.0 for ; Sun, 06 Mar 2016 15:26:25 -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 :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=OortOD/EGC6+x6BDXxjA+PeXJzd0e5d2W1Vkr2aozAU=; b=S7LoZfvilgyWYQtakt/cdpJaHUbvHgjZhnahxg/MvMkHj0G1CbIhFtF2s5XIvdbpUd sEU8wvlIAbiokp0kaWfTWMi8dCPN/oiAopv5WFXD+kJuUP+HgTW510AtEtgG1vE5Z4gd 6kBJUe28Nam+fE/LlnFD99+OBHy+HqpH0ofqB4EhXVVysiidbufIjDb2bz0SOGCS+JLR fsC5YGgGP0yvLmf0eaD84eyuWGDXIHVEzXL+/vcN0PV9i/Bob+mSPAVUIz/9KBLwba6j fUY/4ZSNtLpAUY1eJ+fygB+yLxISlQJzKknV4/NzAsZZx/oXDEIrcgEsctPk+65D76i/ 89iQ== 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: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=OortOD/EGC6+x6BDXxjA+PeXJzd0e5d2W1Vkr2aozAU=; b=lxzGUBmExXdigjVrOsqNQvniuKBKNDl5eTAMjZw9rrGGCbbhvehYasOKM2rUrU4twr JMtn0+M56TcPwm+sqouNIc2Wt5fwDObyMZtpwutQm5YNoJtqJ5wFQB5K4TxzIaR3pgEQ PH+CvNONq1mi526yNdPX83mkBVtd129vpzajbcHrs+s8QrxqU368oAMp2UVvhfmlfW4p Nt1z509f0aZrKh73fVljbLPhY06YPRTXjNrG5q0lqwe8PlNAE0de64RtANRkk/S6IKcR w0wnHq8qW9IOn6lXMXuuLr+r5Gql52ofD8Mq4RQ6ZhCeTbXpRiTUurWOS74RarC1Bz6v 23bA== X-Gm-Message-State: AD7BkJKP4SJMPV0S5Y7XcVk1c2s3KMmvTcY9KEAOXU3Gs2mwFcqAEKwLZBKgXeJhqmb65Q== X-Received: by 10.182.58.66 with SMTP id o2mr10942976obq.1.1457306784765; Sun, 06 Mar 2016 15:26:24 -0800 (PST) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.107.4.2 with SMTP id 2ls800265ioe.10.gmail; Sun, 06 Mar 2016 15:26:23 -0800 (PST) X-Received: by 10.50.109.230 with SMTP id hv6mr154250igb.2.1457306783722; Sun, 06 Mar 2016 15:26:23 -0800 (PST) In-Reply-To: <56DC58FC.9020009@wanadoo.fr> X-Original-Sender: wkaras@yahoo.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: , X-Original-From: Walt Karas Xref: news.gmane.org gmane.comp.lang.c++.isocpp.proposals:25007 Archived-At: ------=_Part_2580_521731145.1457306782711 Content-Type: multipart/alternative; boundary="----=_Part_2581_537660415.1457306782711" ------=_Part_2581_537660415.1457306782711 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On Sunday, March 6, 2016 at 11:21:19 AM UTC-5, Vicente J. Botet Escriba=20 wrote: > > Le 06/03/2016 02:17, 'Walt Karas' via ISO C++ Standard - Future Proposals= =20 > a =C3=A9crit : > > On Saturday, March 5, 2016 at 7:27:24 PM UTC-5, Nicol Bolas wrote:=20 >> >> On Saturday, March 5, 2016 at 7:09:11 PM UTC-5, Walt Karas wrote:=20 >>> >>> On Saturday, March 5, 2016 at 2:21:06 AM UTC-5, Vicente J. Botet Escrib= a=20 >>> wrote:=20 >>>> >>>> Le 05/03/2016 03:08, 'Walt Karas' via ISO C++ Standard - Future=20 >>>> Proposals a =C3=A9crit : >>>> >>>> >>>> >>>> On Friday, March 4, 2016 at 8:22:12 PM UTC-5, Nicol Bolas wrote:=20 >>>>> >>>>> On Friday, March 4, 2016 at 2:53:26 PM UTC-5, Walt Karas wrote:=20 >>>>>> >>>>>> Personally I'm more interested in a generic endiance-swap function= =20 >>>>>> template. The books will be open in 2017, new features will be made= , I'm=20 >>>>>> selfishly thinking of the needs on my own turf. But why not do it i= n a way=20 >>>>>> that is more general, provides for multiple needs? >>>>>> >>>>> >>>>> Yes... that's what *reflection* will do. Your way is the more=20 >>>>> special-case and restrictive way. >>>>> >>>> >>>> Are there other papers proposing support for reflection, besides p0255= r0=20 >>>> ? >>>> >>>> >>>> >>>> >>>> Yes, look at >>>> >>>> http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/. >>>> >>>> Vicente >>>> >>> >>> I think it's a bad choice to not seriously consider a class=20 >>> introspection/reflection capability that can support providing comparis= on=20 >>> operators as library templates. Maybe these do, but it's not clear to = me. >>> >> It depends if yous data is private or not. It is not clear yet what we= =20 > could be able to do reflecting private data. > I suggested one possibility, for "Components" to be a default public class= =20 member. "Components" could also be a default protected class member. So= =20 the class would have to friend a helper class of comparison or other=20 operator templates in order for the default operator to work for the class.= =20 Maybe use of the ++T idiom or Ceiton's keyword-based idioms could be the= =20 equivalent of protected if they accessed private components. A big issue would be, should users of something as basic as comparison=20 operators have to deal with template use error hell-spew? But even the=20 most casual users of C++ should still be using the STL, shouldn't they?=20 I'm not sure it's reasonable to shelter even them from template hell-spew. --=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/8922074a-fe00-4476-a8ef-8ba5840e1338%40isocpp.or= g. ------=_Part_2581_537660415.1457306782711 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
On Sunday, March 6, 2016 at 11:21:19 AM UTC-5, Vicente J. = Botet Escriba wrote:
=20 =20 =20
Le 06/03/2016 02:17, 'Walt Karas' via ISO C++ Standard - Future Proposals a =C3=A9crit=C2=A0:
On Saturday, March 5, 2016 at 7:27:24 PM UTC-5, Nicol Bolas wrote:
On Saturday, March 5, 2016 at 7:09:11 PM UTC-5, Walt Karas wrote:
On Saturday, March 5, 2016 at 2:21:06 AM UTC-5, Vicente J. Botet Escriba wrote:
Le 05/03/2016 03:08, 'Walt Karas' via ISO = C++ Standard - Future Proposals a =C3=A9crit=C2=A0:


On Friday, March 4, 2016 at 8:22:12 PM UTC-5, Nicol Bolas wrote:
On Friday, March 4, 2016 at 2:53:26 PM UTC-5, Walt Karas wrote:
Personally I'm more interested in a generic endiance-swap function template.=C2=A0 The books will be open in 2017, new features will be made, I'm selfishly thinking of the needs on my own turf.=C2=A0 But why not do it in a w= ay that is more general, provides for multiple needs?

Yes... that's what reflection will do. Your way is the more special-case and restrictive way.

Are there other papers proposing support for reflection, besides p0255r0 ?

Yes, look at

http://www.open-std.org/jtc1/= sc22/wg21/docs/papers/2016/.

Vicente

I think it's a bad choice to not seriously conside= r a class introspection/reflection capability that can support providing comparison operators as library templates. =C2=A0Maybe these do, but it's not clear t= o me.
It depends if yous data is private or not. It is not clear yet what we could be able to do reflecting private data.
<= div>
I suggested one possibility, for "Components" = to be a default public class member. =C2=A0"Components" could als= o be a default protected class member. =C2=A0So the class would have to fri= end a helper class of comparison or other operator templates in order for t= he default operator to work for the class. =C2=A0Maybe use of the ++T idiom= or Ceiton's keyword-based idioms could be the equivalent of protected = if they accessed private components.

A big issue w= ould be, should users of something as basic as comparison operators have to= deal with template use error hell-spew? =C2=A0But even the most casual use= rs of C++ should still be using the STL, shouldn't they? =C2=A0I'm = not sure it's reasonable to shelter even them from template hell-spew.<= /div>

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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/8922074a-fe00-4476-a8ef-8ba5840e1338= %40isocpp.org.
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