220 34727 article Path: news.gmane.org!.POSTED!not-for-mail From: Zhihao Yuan Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Re: Concepts are Adjectives, not Nouns Date: Mon, 9 Oct 2017 21:38:10 -0500 Lines: 175 Approved: news@gmane.org Message-ID: References: <7e0b8951-a46a-470d-bb7c-1651e6c4d707@isocpp.org> <22229cfe-0d43-5c01-cef4-b6502de658c1@honermann.net> <9fb3dbcb-87ab-a6fe-dd71-c6ed08309161@honermann.net> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: multipart/alternative; boundary="94eb2c1256fcc0fda3055b2832eb" X-Trace: blaine.gmane.org 1507603096 22299 195.159.176.226 (10 Oct 2017 02:38:16 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Tue, 10 Oct 2017 02:38:16 +0000 (UTC) To: "std-proposals@isocpp.org" Original-X-From: std-proposals+bncBCSKRWMD4EHBBFPF6DHAKGQE2SNIBQQ@isocpp.org Tue Oct 10 04:38:11 2017 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-ua0-f199.google.com ([209.85.217.199]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1e1kQo-0004ka-SD for gclcip-std-proposals@m.gmane.org; Tue, 10 Oct 2017 04:38:07 +0200 Original-Received: by mail-ua0-f199.google.com with SMTP id s9sf9818991uae.14 for ; Mon, 09 Oct 2017 19:38:14 -0700 (PDT) ARC-Seal: i=2; a=rsa-sha256; t=1507603094; cv=pass; d=google.com; s=arc-20160816; b=Ni7zupmzui70Tc+okgGrWsfe3+1U6HKHs6aTljxTE4SJT5FlKIXU1Vn+IROqn+8L5J MQr+ZSTKzKyJdXOtDO+4l653GH6ezESvXypHdsnh/lfDYoDIR/OzmxqsdBMIf4i7xZOe FDLjxGWqF3BCmW0aHzOuo1KnWFE8B20F1NOoE4ULAtsLzCYkfsumJceX0s9sxCAIO79g do2KxfSHNZZIXZFJrVSpwjjRNReTFahYK3g5d8KxixMO4dU7rc8w0Hk1BTxTfLXLmHVK Esq+8+RnNIkHPMXCk2q+MFKzh89H5gr35h9T2ILsi3qsxU8V/A2mNekMVRdf0064FL8V PIjw== ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-unsubscribe:list-subscribe:list-archive:list-help:list-post :list-id:mailing-list:precedence:reply-to:to:subject:message-id:date :from:references:in-reply-to:mime-version:sender :arc-authentication-results:arc-message-signature :arc-authentication-results; bh=mqyADqNgaTZrijz7TLGlOPdp2KYZoX5XBIg3GVPgBMc=; b=kVNIdKduOkiuqHfsss/1Pfdh4yu9bBilWpTWjSPowm9K9ydAvvIypvzr3wLTQ6iRII nkCnfx47sYkKKkwTdBHMV8I1UasymEmCUbvgnhCODrbFXXPoExClyYufg7CBhE2HHIQH nJ/3Q9ibvCVQoDnFl0ljsCLGxYsDr26BKcMgOX/lnvERG9QkMKkRzblRoaBdF8JQGLSb ZC8wwglxqJ5WXpgOOb6cGdVnkcAhiy+xCppSBhwlIer8+i2iaCNyOWe1+yguQSw9yBKE tdl2yaF7Y6DqVwp7cM1oUuxrtdyZQfNseYYC3vf7F82KpcOewEik7ZouetMSwjywJlPo kwZA== ARC-Authentication-Results: i=2; mx.google.com; dkim=pass header.i=@miator.net header.s=krs header.b=bOxVhLwX; spf=pass (google.com: domain of bounce+3f9131.69110-std-proposals=isocpp.org@miator.net designates 184.173.153.196 as permitted sender) smtp.mailfrom=bounce+3f9131.69110-std-proposals=isocpp.org@miator.net X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:mime-version:in-reply-to:references: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=mqyADqNgaTZrijz7TLGlOPdp2KYZoX5XBIg3GVPgBMc=; b=XOPyPmf3iiUSajtoJWgtj3AHoRhqB56U8lRpGdtzmp/r5SQkbxGSiCLK3t7LNpEOXp zuC84L8OArx0+pp3WCbaB8Ht15MgCFQQbIDgkpXs3Iw3QJbBmFn1RzlCpsPYjme0AkiR MO4cwviUgXj98QTfzeXcw4DT28uQr6QvFlMussMd9qRnRD67zaINCutw7v2gve8YfWxF EaMpr05IusUDSV/vusj4QsSWx3YjlWk9/9g9nncHZUhdtSp/plZJSYvshlvT9T5RJo6E I5HFiGW1Yl2Mwsr+OocHusBSEaU8UAsSVr/+IRYoVPF+Hx9R5QdquFyBvlgmljqKjy8O 0/Uw== X-Gm-Message-State: AMCzsaX16d/wc9NSqFcuJuqDtU+9a4SUINcziqyuyMkxAnptpGkVoYvA dt8fCDrEU4ktB3g+fRzyddUSlQ== X-Google-Smtp-Source: AOwi7QAhfSbHUn4BMiRhsOU6Z89iW4EYx+ecD0fKAaBK3sSupK+n55z+0BaUl7m/ngMIZOczmA2Gbw== X-Received: by 10.55.17.225 with SMTP id 94mr5554910qkr.43.1507603093993; Mon, 09 Oct 2017 19:38:13 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.55.167.196 with SMTP id q187ls2446198qke.14.gmail; Mon, 09 Oct 2017 19:38:13 -0700 (PDT) X-Received: by 10.55.122.135 with SMTP id v129mr8861319qkc.171.1507603093334; Mon, 09 Oct 2017 19:38:13 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1507603093; cv=none; d=google.com; s=arc-20160816; b=dGv5Qc2aNMnuq7pmHJXZEMfSeF1kaydWQTu7J7maBHT7vIg7eNHTHeCdHiNiAQiatX xD1hn486aXDjtaoIiIQYrHqVAf/CiR8QGr0KKvpONMnpsn+2vKvIQ+QD03eVwMRnmveR ZlH3mlhVn2FDGy+O+1etPup4CXWBA10TbO2mNJ1mGfJGw037pE9TClLnRZRinVgV/Rbw tY2KEzJO91WoNkiEaWA+WStLzYnyyQ/4AfFZ/1PzvNU2nFQJtkaxuLD/8/i6riS9jZ9D DxSrIIvF7mA8JgqP/gFw4uVxMYQPrCPG4EAJ21+HMxn+FOHZFazt9C/y1Y+x5xAVXR1D 1CLw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=to:subject:message-id:date:from:references:in-reply-to:mime-version :sender:domainkey-signature:dkim-signature :arc-authentication-results; bh=+9T1OpM4EF//ltQIiE1dLPZRBaGl4OJ8Y/TmAiuqBfQ=; b=VXGxhOukEPUiOQjIrgStCNp9yhSh3hTr7NPVybyRYaV0ruh4XUpnPrGUPKAAsm6RfO a668dwszHOiTyXsva1rO1MBCIoIeOtuq2AFaOhfrEVRTYuf90s1ggeIUsN28pOzuO9QJ /qkzmXAMqiZ0gQy5tqjO6HU+uFyj7gc98i1l15kPJ6cL0gW2+4mw3qnVsm4LJaCLbIKf Bl+kC/tmC7P6EHb/fsmIfyoNjvqvgNON8NVztMf8YuXT+fQljc5ihMOoF6TVwBdPwX7H ZjNwUe/Vj0OaVVZUg3+0jmJxXUiMqj7DmTqW2Jy1v/Q+CIMGjttF42k5QrnjDgW7h/h6 cEZQ== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@miator.net header.s=krs header.b=bOxVhLwX; spf=pass (google.com: domain of bounce+3f9131.69110-std-proposals=isocpp.org@miator.net designates 184.173.153.196 as permitted sender) smtp.mailfrom=bounce+3f9131.69110-std-proposals=isocpp.org@miator.net Original-Received: from mail-s68.mailgun.info (mail-s68.mailgun.info. [184.173.153.196]) by mx.google.com with UTF8SMTPS id c6si5240882qtg.57.2017.10.09.19.38.13 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 09 Oct 2017 19:38:13 -0700 (PDT) Received-SPF: pass (google.com: domain of bounce+3f9131.69110-std-proposals=isocpp.org@miator.net designates 184.173.153.196 as permitted sender) client-ip=184.173.153.196; Original-Sender: zy@miator.net X-Mailgun-Sending-Ip: 184.173.153.196 X-Mailgun-Sid: WyI3MTBkYiIsICJzdGQtcHJvcG9zYWxzQGlzb2NwcC5vcmciLCAiNjkxMTAiXQ== Original-Received: from mail-qt0-f175.google.com (mail-qt0-f175.google.com [209.85.216.175]) by mxa.mailgun.org with ESMTP id 59dc3294.7fedd84e5b70-smtp-out-n02; Tue, 10 Oct 2017 02:38:12 -0000 (UTC) Original-Received: by mail-qt0-f175.google.com with SMTP id z19so1799758qtg.11 for ; Mon, 09 Oct 2017 19:38:12 -0700 (PDT) X-Received: by 10.237.44.194 with SMTP id g60mr17907265qtd.92.1507603091879; Mon, 09 Oct 2017 19:38:11 -0700 (PDT) Original-Received: by 10.237.50.38 with HTTP; Mon, 9 Oct 2017 19:38:10 -0700 (PDT) In-Reply-To: <9fb3dbcb-87ab-a6fe-dd71-c6ed08309161@honermann.net> X-Gmail-Original-Message-ID: X-Original-Sender: zy@miator.net X-Original-Authentication-Results: mx.google.com; dkim=pass header.i=@miator.net header.s=krs header.b=bOxVhLwX; spf=pass (google.com: domain of bounce+3f9131.69110-std-proposals=isocpp.org@miator.net designates 184.173.153.196 as permitted sender) smtp.mailfrom=bounce+3f9131.69110-std-proposals=isocpp.org@miator.net 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:34727 Archived-At: --94eb2c1256fcc0fda3055b2832eb Content-Type: text/plain; charset="UTF-8" On Mon, Oct 9, 2017 at 7:12 PM, Tom Honermann wrote: > On 10/09/2017 06:36 PM, Zhihao Yuan wrote: > > template > void foo(T x); > > The inconsistency argument is that in every other context in which we see > something like 'Red T', T names a non-type (variable, data member, > function) entity. > Haskell does the opposite, so I totally don't mind. > While I (so far) don't find these issues strongly concerning, the fact > that the concepts-as-abbreviations proposal fixes them while providing a > more useful syntax (the ability to compose concepts without having to name > them or reach for a requires clause) is welcome, encouraging, and > suggestive of stronger design cohesion. > I wish I don't have to define a macro for each concept, #define Red(x) Red typename x template just to stay away from the noises. Haskell solves this by template <(Red T, TotallyOrdered T)> And of course, some folks just really really don't like the template header > and the requirement to name the type parameter. > > I think we need to establish a rule, saying that changing a syntax caused by "dislike" requires you hate it enough by inventing macros. Thus, you find that its ugliness overwhelmed that of macros; otherwise the hatred isn't enough. Yes. But so far, every use of a disjunction I've seen has been trivially > replaced (for performance reasons) with a constexpr function that evaluates > the disjunction. For example: > > https://github.com/tahonermann/text_view/blob/master/ > include/text_view_detail/concepts.hpp#L30-L70 > > I haven't thought about it deeply, but I think the semantic concepts > changes from P0717R0 [1] adopted in Toronto have further reduced the use > cases for disjunctive concepts. > > That makes sense. I don't have a use case for doing refinement over concept disjunctions. A. Sutton can correct me :) -- Zhihao Yuan, ID lichray The best way to predict the future is to invent it. _______________________________________________ -- 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/CAGsORuA%3Dz6XzT%2BJgH83%2Bn3jV2pzeKjHp5mBRz4oD0y1m4HAz%2Bg%40mail.gmail.com. --94eb2c1256fcc0fda3055b2832eb Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
On Mon, Oct 9, 2017 at 7:12 PM, Tom Honermann <tom@honerm= ann.net> wrote:
=20 =20 =20
On 10/09/2017 06:36 PM, Zhihao Yuan wrote:
=C2=A0 template <Red T>
=C2=A0 void foo(T x);
 The inconsistency argument is that in every other context in which we see something like 'Red T', T names a non-type (variable, da= ta member, function) entity.

Has= kell does the opposite, so I totally don't mind.
=C2=A0
While I (so far) don't find these issues strongly concerning, the fact that the concepts-as-abbreviations proposal fixes them while providing a more useful syntax (the ability to compose concepts without having to name them or reach for a requires clause) is welcome, encouraging, and suggestive of stronger design cohesion.

I wish I don't have to define a ma= cro for each concept,

=C2=A0 #define Red(x) Red typename = x
=C2=A0 template <Red(T)>

just to stay away from the noises.

Haskell solves this b= y

=C2=A0 template <(Red T, TotallyOrdered T)>


And of course, some folks just really really don't like the templat= e header and the requirement to name the type parameter.


I think we need to es= tablish a rule, saying that changing
a syntax caused by "= ;dislike" requires you hate it enough
by inventing macro= s.=C2=A0 Thus, you find that its ugliness
overwhelmed that of macros; ot= herwise the hatred isn't
enough.

Yes.=C2=A0 But so far, every use of a disjunction I've seen has been trivially replaced (for performance reasons) with a constexpr function that evaluates the disjunction.=C2=A0 For example:

https://github= ..com/tahonermann/text_view/blob/master/include/text_view_detail/<= wbr>concepts.hpp#L30-L70

I haven't thought about it deeply, but I think the semantic concept= s changes from P0717R0 [1] adopted in Toronto have further reduced the use cases for disjunctive concepts.


That makes sen= se.=C2=A0 I don't have a use case for doing
refinement over concept = disjunctions.=C2=A0 A. Sutton can
correct me :)

--
Zhihao Yuan,= ID lichray
The best way to predict the future is to invent it.
_____= __________________________________________
=

--
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/CAGsORuA%= 3Dz6XzT%2BJgH83%2Bn3jV2pzeKjHp5mBRz4oD0y1m4HAz%2Bg%40mail.gmail.com. --94eb2c1256fcc0fda3055b2832eb-- .