220 11837 <5FB75AC7-90B8-4958-AB87-9EA9C259412A@gmail.com> article Path: news.gmane.org!not-for-mail From: David Krauss Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: N4115, N3728: std::tuple as metadata Date: Fri, 11 Jul 2014 16:13:57 +0800 Lines: 87 Approved: news@gmane.org Message-ID: <5FB75AC7-90B8-4958-AB87-9EA9C259412A@gmail.com> References: <6598852E-AFEC-4637-A912-725D59B8D748@gmail.com> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 (Mac OS X Mail 7.3 \(1878.6\)) Content-Type: multipart/alternative; boundary="Apple-Mail=_224258EE-A7E7-4F82-9300-EDDA0D9573EC" X-Trace: ger.gmane.org 1405066454 12037 80.91.229.3 (11 Jul 2014 08:14:14 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Fri, 11 Jul 2014 08:14:14 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBCW25A7E3QCRBS5Z72OQKGQEGH4TCCA@isocpp.org Fri Jul 11 10:14:08 2014 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-qg0-f70.google.com ([209.85.192.70]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1X5Vy1-0002eQ-1T for gclcip-std-proposals@m.gmane.org; Fri, 11 Jul 2014 10:14:05 +0200 Original-Received: by mail-qg0-f70.google.com with SMTP id i50sf1661964qgf.1 for ; Fri, 11 Jul 2014 01:14:04 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:message-id:mime-version:subject:date :references:to:in-reply-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=+CxHXuGpmwEnXnUxwdqIrGQdH5aSC4Q35HRXHOh2IWg=; b=bof4srGGtcJ4fyXssyKBjvkmjvjyEF1N8Aac7je+ITC5wm93UQg8s/HiyzWDVqsps9 Gc8VN8Esmacr3J+AVL7yqC7W3W6b1rKZCunYmBDnfALeJjJ/WJ1sYayvqQg59sV1FMsL 60wfHhl10YRn/yFt80eaE8vieQJeu2Ji5HlMMSWp89lB0VZf7aR0glYzO4/SiO8TCnB8 3KB/Bgc8yoYvZMEPwxT+sjZI0bredpJIm9hR4nbZhFcstkOaK7sqwO3m066QsyMxzkf5 x5nqiC4MLijTvYWYKmUXdRETogf7hUp1pUdX9BiiOy/lohmPh33uUHdVW6UYEzIY8wGs 2EPA== X-Gm-Message-State: ALoCoQk9CcG9cxNHEHx17fQvUnkBz/UGGaS8KdsBruSb8cdTa+Qia56u4jjm7IM1CmQEvFlqHz1m X-Received: by 10.236.133.237 with SMTP id q73mr5139213yhi.52.1405066444248; Fri, 11 Jul 2014 01:14:04 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.50.61.138 with SMTP id p10ls244648igr.22.canary; Fri, 11 Jul 2014 01:14:03 -0700 (PDT) X-Received: by 10.42.78.208 with SMTP id o16mr2969025ick.16.1405066443602; Fri, 11 Jul 2014 01:14:03 -0700 (PDT) Original-Received: from mail-ie0-x235.google.com (mail-ie0-x235.google.com [2607:f8b0:4001:c03::235]) by mx.google.com with ESMTPS id dr7si3402980icb.101.2014.07.11.01.14.03 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Fri, 11 Jul 2014 01:14:03 -0700 (PDT) Received-SPF: pass (google.com: domain of potswa@gmail.com designates 2607:f8b0:4001:c03::235 as permitted sender) client-ip=2607:f8b0:4001:c03::235; Original-Received: by mail-ie0-f181.google.com with SMTP id rp18so592123iec.26 for ; Fri, 11 Jul 2014 01:14:03 -0700 (PDT) X-Received: by 10.50.114.197 with SMTP id ji5mr2419037igb.48.1405066443499; Fri, 11 Jul 2014 01:14:03 -0700 (PDT) Original-Received: from [172.20.10.2] ([121.54.54.43]) by mx.google.com with ESMTPSA id d4sm3947524igc.5.2014.07.11.01.14.02 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Fri, 11 Jul 2014 01:14:03 -0700 (PDT) In-Reply-To: X-Mailer: Apple Mail (2.1878.6) X-Original-Sender: potswa@gmail.com X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of potswa@gmail.com designates 2607:f8b0:4001:c03::235 as permitted sender) smtp.mail=potswa@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:11837 Archived-At: --Apple-Mail=_224258EE-A7E7-4F82-9300-EDDA0D9573EC Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=ISO-8859-1 On 2014-07-11, at 4:03 PM, Ville Voutilainen = wrote: > Ah, all implementations have figured out a way to ensure the problem > doesn't happen, > great. After reading N3728, it gives rather more reasons for not using > tuple. Apparently > all of those are now moot. Well, points about convenience may still have merit. But it's a stretch to = say we need a dedicated facility. Essentially it comes down to providing a = shortcut to specialization matching. > Quite many people consider using pair as the element of maps a > mistake, since the > simple utility type gets feature bloat from the requirements of the > container. Perhaps > it would be a similar mistake to couple parameter pack access and > potentially also > reflection facilities with tuple. That's the thing about a non-instantiated template (may as well be an incom= plete class): It has no features whatsoever. Whatever other name you give t= ype_list, the facilities that use it should as a rule not instantiate it, b= ecause that takes compiler time and memory. --=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/. --Apple-Mail=_224258EE-A7E7-4F82-9300-EDDA0D9573EC Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=ISO-8859-1
On 2014&= ndash;07–11, at 4:03 PM, Ville Voutilainen <ville.voutilainen@gmail.com> wrote:
Ah, all imp= lementations have figured out a way to ensure the problem
doesn't happen= ,
great. After reading N3728, it gives rather more reasons for not using=
tuple. Apparently
all of those are now moot.
Well, points about convenience may still have merit. But it&rs= quo;s a stretch to say we need a dedicated facility. Essentially it comes d= own to providing a shortcut to specialization matching.

Quite many people consider using pair as the element of map= s a
mistake, since the
simple utility type gets feature bloat from th= e requirements of the
container. Perhaps
it would be a similar mistak= e to couple parameter pack access and
potentially also
reflection fac= ilities with tuple.

That’s the t= hing about a non-instantiated template (may as well be an incomplete class)= : It has no features whatsoever. Whatever other name you give type_list, the facilities that use it should as a rule not= instantiate it, because that takes compiler time and memory.

--

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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.
Visit this group at http://groups.google.com/a/isocpp.org/group/std-proposals/<= /a>.
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