220 32116 article Path: news.gmane.org!.POSTED!not-for-mail From: Jakob Riedle Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Allow constexpr static data members in a literal type. Date: Wed, 19 Apr 2017 05:58:54 -0700 (PDT) Lines: 84 Approved: news@gmane.org Message-ID: References: Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_Part_7264_1583466568.1492606734756" X-Trace: blaine.gmane.org 1492606738 28375 195.159.176.226 (19 Apr 2017 12:58:58 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Wed, 19 Apr 2017 12:58:58 +0000 (UTC) To: ISO C++ Standard - Future Proposals Original-X-From: std-proposals+bncBCX2XNFO6MPRBD563XDQKGQE4UG4PGQ@isocpp.org Wed Apr 19 14:58:51 2017 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-it0-f69.google.com ([209.85.214.69]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1d0pC6-0007E2-Qh for gclcip-std-proposals@m.gmane.org; Wed, 19 Apr 2017 14:58:51 +0200 Original-Received: by mail-it0-f69.google.com with SMTP id 67sf9817386ite.6 for ; Wed, 19 Apr 2017 05:58:56 -0700 (PDT) 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=UQZdExyJnBIjj8sXRPTiHYle4ONHFGJw/7xKgq53dB4=; b=Q17ZF8GKr3zD4DX4mcaXO6FHiYK4lt4oTbgLECcWH8Nz0wbdW0qTYJYRE568Acr/LM BwyOtmVN5Db2pZJzofT65IjSJV15kJAVv08ZIzX4EO2tct7UswnKZ/ZPnUKMCxhWcIYz sYp5H+wWFtSEI21PUntAOy8nIxfeEIZxU/6JSbqSLsxtY+/EAzEyUI4JG9E7PC1INB59 sskoLBRDYRqYsGR4v2kXRlkv6RxQs1/JuE5Q1Z8S5kyDQIHV9lpu6Xb1NdPIo4Ry5NRn 1AmqqFvFR5cQMsxcR7n/QIXroUFne/wfAF7ss2TXJhvL/mDRthIks7YQt8vHqOryesvy pVcA== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; 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=UQZdExyJnBIjj8sXRPTiHYle4ONHFGJw/7xKgq53dB4=; b=utKeaSJfmPuZE0hSTeF3d2/sV6zaLnKuvdUDQiipCrAzEFdVLoOgld4vMqBV7APBQI rIAkcuqhLbUGCHxK4o+tTxyrEekE/WRp5MlfmXhG3UgYik2iAeRXfcP97BAvIDZ/fkb2 JkzLDI4alJlDITOs+aM9O1IYdkYEifOFZxO1VJJ5Fhc/2bU0YnCR4eJlBGv3vXAjgKY3 A24KS1dRcBQHhCFSqQVbadP7rWAwS1jBXADCGAxTDCq83+8Ry6/psKnC4ZmvIOMMKdxj pbfosdIo4PnYtd/MzPVuToTwzU3JxPoURPAyGzWFp9dAQTi8qL5FqH36wW5xLGJfF20q ZrQA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; 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=UQZdExyJnBIjj8sXRPTiHYle4ONHFGJw/7xKgq53dB4=; b=hIzb0E9Il1NivuiYzCZKVpHzgXNTKBwupZ/uMddxfp7HmfXPEAZTdkmP70y8lyE1DF 5u9NnFlfXjznr95OoZJTq58Rwp468cZ2RUOpfJEedzQiNGsqZDkPRNZTHDQwcZbNFZ3J AYN2daw/0xzXsi08DNEVVbkXH0Vsb/okF4CtmDe0cjA2TzmlvBl9wCT6JNvGyPFesM6S I0K9Z3GMwfmFrdr6Rpb2Tz4l9BIZc2gZqwVWxEk5W7XmJMyrDu8xF4HLQsc4Vlm7yx9N UroLNquvmGlvzvmJrTu+e2lWgX366/APOiUHb+7Aye3QDQI1Mid5AFVY0MEaCBrAZ9Rp 7T+w== X-Gm-Message-State: AN3rC/49NIPOvn5umIUEGQ0MWA38bahkG4Eoo1LdNAzWEu4PoniT8HoD TopbCr7ptsJYvA== X-Received: by 10.107.140.198 with SMTP id o189mr1307893iod.60.1492606736384; Wed, 19 Apr 2017 05:58:56 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.157.19.72 with SMTP id q8ls3017744otq.23.gmail; Wed, 19 Apr 2017 05:58:55 -0700 (PDT) X-Received: by 10.157.26.98 with SMTP id u31mr61105otu.0.1492606735300; Wed, 19 Apr 2017 05:58:55 -0700 (PDT) In-Reply-To: X-Original-Sender: jakob.riedle@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:32116 Archived-At: ------=_Part_7264_1583466568.1492606734756 Content-Type: multipart/alternative; boundary="----=_Part_7265_463703066.1492606734756" ------=_Part_7265_463703066.1492606734756 Content-Type: text/plain; charset=UTF-8 > > Should we make this legal? It seems reasonable for types to offer > constants scoped under their own name, and if they are literal types, > that these constants can be constexpr. > I really like the idea of being able to do that and I had that scenario quite often, e.g. with a Color-Class that defines several constants, such as WHITE, BLACK ... The problem with defining the attributes outside the class, is that you cannot declare this stuff in a header file and include it multiple times. However, this problem is solved by Inline Variables . Still, having to define *constexpr static *class variables outside of the class is *neither pretty nor intuitive*. *Note*: *Java supports this feature for a long time already.* *M(atlab) also supports this. (Using a section named "enumeration" within the "classdef" itself).* Given these reasons, I'm greatly convinced, this is a good thing and should be written a paper for. -- 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/a163f3bd-906e-4dc4-894b-0aae6d2b2e89%40isocpp.org. ------=_Part_7265_463703066.1492606734756 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
Should we mak= e this legal? =C2=A0It seems reasonable for types to offer=C2=A0
constan= ts scoped under their own name, and if they are literal types,=C2=A0
tha= t these constants can be constexpr.=C2=A0

I really like the idea of being able to do that and I had that scenario = quite often,
e.g. with a Color-Class that defines several constan= ts, such as WHITE, BLACK ...
The problem with defining the attrib= utes outside the class,
is that you cannot declare this stuff in = a header file and include it multiple times.

Howev= er, this problem is solved by=C2=A0Inline Variables.
Still= , having to define constexpr static=C2=A0class variables outside of = the class is neither pretty nor intuitive.

= Note: Java supports this feature for a long time already.
M(atlab) also supports this. (Using a section named "enumera= tion" within the "classdef" itself).

Given these reasons, I'm greatly convinced, this is a good thing = and should be written a paper for.

--
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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/a163f3bd-906e-4dc4-894b-0aae6d2b2e89= %40isocpp.org.
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