220 24981 <7e46c46d-2e18-4cec-92c1-4f4d7fbc786b@isocpp.org> article Path: news.gmane.org!not-for-mail From: Nicol Bolas Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: "Components" template with implicitly defined partial specializations for all classes Date: Sat, 5 Mar 2016 16:27:24 -0800 (PST) Lines: 182 Approved: news@gmane.org Message-ID: <7e46c46d-2e18-4cec-92c1-4f4d7fbc786b@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> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_Part_459_24067788.1457224044550" X-Trace: ger.gmane.org 1457224054 18120 80.91.229.3 (6 Mar 2016 00:27:34 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Sun, 6 Mar 2016 00:27:34 +0000 (UTC) To: ISO C++ Standard - Future Proposals Original-X-From: std-proposals+bncBCEKFTV6ZUMBB3PS5W3AKGQEUCRXGVA@isocpp.org Sun Mar 06 01:27:28 2016 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-pf0-f200.google.com ([209.85.192.200]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1acMXf-0000ji-LA for gclcip-std-proposals@m.gmane.org; Sun, 06 Mar 2016 01:27:27 +0100 Original-Received: by mail-pf0-f200.google.com with SMTP id 184sf151688403pff.3 for ; Sat, 05 Mar 2016 16:27:27 -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=9Rb8ebAfHT+6NG1GBdbpDkd+SQCvBOvbzEj37GK6Dv4=; b=gzKiUW/8ZfJToA4YbZ/lBvQ22ZAtYih3nqjWAJbqWI5oio5qBScZzdqh/XKeXlXc0r 36VWJRxgZxAggglUngPp7L27HeajPN0Nwq+13Cd60jCYO28kekyGDFOJRRYNATouOzxs QCe/+cvai5vzzOMFB1UxeWWu6z1K2fOl9ynmVyB35/xlV1z09ExI1Xg4igriUTCDNTEp YjtnLkii8r201VUW06CM24keE2Mti9Z1c/V96bAN+KnDLEOVWDGq9ZEF9fY2pfEgl/V3 rhrFrUf1gTHGuLNA4X4i0GBpQ1cfuuROwB0hsWfwbe7AaX7C0XSjI/SNgpehDKIAekjM r48w== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; 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=9Rb8ebAfHT+6NG1GBdbpDkd+SQCvBOvbzEj37GK6Dv4=; b=dudOU0TEOKFs6bkJEOkVxFhxSIIHYvuuXD4e4Afzcoss9dXzsg+cFMRe3sgszi2KGC 2A0wIkFAT7emU60shww0X/SkX6jIG2/Lt6jR4xbrfaB25cczhYHRmT8o7Z66W1kZs92P 9b4Ap4S9k+j5+iSruoL0rXfTSpuLJ7G0OuZCUlHxWOTk3Qqdb3lTqcs1ilJhKBcDh0c4 7rWv0XhVZwvhKJ7sDvsPCWNcz1PORI39+Mr6N89dfMbYVVqUHpy1pIMv4fgPPumwWBAB dIWlGYxX7MklbLuCvH5hKLpEcxKafmfNCloswJtR3M1aqUZNjFAloItLQsny0xnWEblL n7cQ== 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=9Rb8ebAfHT+6NG1GBdbpDkd+SQCvBOvbzEj37GK6Dv4=; b=XJB5RA3zI0yaC6DYxfPCKse+/Nc7awjnJiXjazYgMyEafd6wbcnEA4RlwmUMF4Gp9w L12RsGT+ttiUPiPwQZl8QgPrDGocRzkeHfCw6MtzsIaPs3E+TMVcxZ9kZuVJAvUszyyL B1QT30U+DvqTU5dhNrS8JX6Eate6MnKCztg/lY2/g/EBjPW2f20ujDGyaRG4ClfIkLVj 7zysA15dYliMRXgeZmLRzJKTGhhjZi1S7hKr8vSNotuLyvHkyOWjwG5L7PmRylMnJaMe QqX8ibf5oT9DwoDauuzuhANjSChRVrEb29QwabEG76/4z6n5X2324Y5Ta5DP4faHIWBX IkTQ== X-Gm-Message-State: AD7BkJLI1pIP1xbD1rjkmw241ByqRYO39NiEeDuPkkq2WmXheTZCZLTGJDaSGkB6gqTA8g== X-Received: by 10.67.10.209 with SMTP id ec17mr9559220pad.43.1457224046662; Sat, 05 Mar 2016 16:27:26 -0800 (PST) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.50.30.101 with SMTP id r5ls555250igh.40.gmail; Sat, 05 Mar 2016 16:27:25 -0800 (PST) X-Received: by 10.50.111.100 with SMTP id ih4mr108885igb.3.1457224045536; Sat, 05 Mar 2016 16:27:25 -0800 (PST) In-Reply-To: X-Original-Sender: jmckesson@gmail.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: , Xref: news.gmane.org gmane.comp.lang.c++.isocpp.proposals:24981 Archived-At: ------=_Part_459_24067788.1457224044550 Content-Type: multipart/alternative; boundary="----=_Part_460_835142945.1457224044550" ------=_Part_460_835142945.1457224044550 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable 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= =20 > wrote: >> >> Le 05/03/2016 03:08, 'Walt Karas' via ISO C++ Standard - Future Proposal= s=20 >> 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 in = 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 p0255r0= =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 comparison= =20 > operators as library templates. Maybe these do, but it's not clear to me= .. > .... why bother? With default operators=20 ,=20 generating comparison operators won't be a significant use case for=20 reflection. Now, that doesn't mean you won't want to do it sometimes. But= =20 most of the time, no. Also, just because one reflection proposal doesn't have something doesn't= =20 mean that others won't. Compile-time reflection is hard to get right. --=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/7e46c46d-2e18-4cec-92c1-4f4d7fbc786b%40isocpp.or= g. ------=_Part_460_835142945.1457224044550 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
On Saturday, March 5, 2016 at 7:09:11 PM UTC-5, Walt Karas= wrote:
On Sat= urday, March 5, 2016 at 2:21:06 AM UTC-5, Vicente J. Botet Escriba wrote: =20 =20 =20
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 gene= ric endiance-swap function template.=C2=A0 The books will be op= en 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 way 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/pap= ers/2016/.

Vicente

I think it's a ba= d choice to not seriously consider a class introspection/reflection capabil= ity that can support providing comparison operators as library templates. = =C2=A0Maybe these do, but it's not clear to me.

... why bother? With default operators, generating comp= arison operators won't be a significant use case for reflection. Now, t= hat doesn't mean you won't want to do it sometimes. But most of the= time, no.

Also, just because one reflection proposal doesn't ha= ve something doesn't mean that others won't. Compile-time reflectio= n is hard to get right.

--
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