220 31428 <097e0a3f-275d-45e7-babb-d3f80e1fa83d@isocpp.org> article Path: news.gmane.org!.POSTED!not-for-mail From: lev@compuserve.com Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Re: Math constants Date: Sat, 4 Mar 2017 13:40:13 -0800 (PST) Lines: 118 Approved: news@gmane.org Message-ID: <097e0a3f-275d-45e7-babb-d3f80e1fa83d@isocpp.org> References: <8aec2d3e-60e3-4dbf-890d-3450a32ca6d3@isocpp.org> <7327f25a-3d77-4d97-808e-678b3458ee52@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_Part_672_1959060678.1488663613107" X-Trace: blaine.gmane.org 1488663616 30154 195.159.176.226 (4 Mar 2017 21:40:16 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Sat, 4 Mar 2017 21:40:16 +0000 (UTC) To: ISO C++ Standard - Future Proposals Original-X-From: std-proposals+bncBCL6TUMOQUJRBPPI5TCQKGQENINRJPQ@isocpp.org Sat Mar 04 22:40:10 2017 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-yw0-f199.google.com ([209.85.161.199]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1ckHPM-0007BU-Th for gclcip-std-proposals@m.gmane.org; Sat, 04 Mar 2017 22:40:09 +0100 Original-Received: by mail-yw0-f199.google.com with SMTP id v76sf2501458ywg.4 for ; Sat, 04 Mar 2017 13:40:15 -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=RKtqYtK8Z+wVyopUF7+Ja42dFR0FUS3zH7hsAStIpRg=; b=1eWDSFs+OlL5RHSxLthB71HOgNnVcOMFUxkDtmCCd4P8E2zXbi3pJciuRUoSDLzUvO /iLKaclPRI3DgZ2HKnPdkuW+8bkootwuxk4l1lQOoJeIwDADmynsCuajf/iLYpQIo6uS BhWLRe5nWiFPa0greDKJc+2NRm0Q3tRmdKo7ZTC80T06ecOZUs6wjhb9X5beSrbiYyc0 bltTP1T9wLWH/ceKMAVe+5kTNgrmQSzNJ0QDWu81p/nzUfJ3kNRimXkQTIidntV5uEbH vo3eHTx5uEL316MDJG5FZnU93q4T37W18oRFtd2BwC42fx3+szxtxGRMJSpuaR9vMSY7 52+w== 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=RKtqYtK8Z+wVyopUF7+Ja42dFR0FUS3zH7hsAStIpRg=; b=ixwbP9WZjolzcC4qjlGBx1VhEhj+rp6YeZDqBXYOPj9yrDRHG3Zcr4F7jTV75gC+xe taXQzraC6/nJGE5eVgI5fRl2qGlS9baELG8n9QDg6EfDzb5CbnJSQytW0ixEo6fLrG63 vVaVta9AsMB4ZogmZvKTfn+gQeuvf9b5xMjnA3Ls67McSxI3TLRnrcqdVt+2UNRFrjMu X69YF1DZPn64+OTl1oQkCQyTSeJPjCpLjrm/TPSFObCT9Iq0EbVQ/mtRj7FEwB4vvbso sm3o7WxeAmCjL5LOyvjtnULMYnvDQeDJpM8CztVtEFzxBMaI51DaTtR9p8CY4s3Augvt z4SA== X-Gm-Message-State: AMke39kHQa8pLdbU/dHZxVx2Khlf6ms2cAAaLKhEXl6xVTrci4C8qmBqq3fzEhAbOdGseQ== X-Received: by 10.129.105.130 with SMTP id e124mr4216993ywc.2.1488663614689; Sat, 04 Mar 2017 13:40:14 -0800 (PST) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.157.7.18 with SMTP id 18ls1141665ote.1.gmail; Sat, 04 Mar 2017 13:40:13 -0800 (PST) X-Received: by 10.157.22.200 with SMTP id s8mr184627ots.16.1488663613674; Sat, 04 Mar 2017 13:40:13 -0800 (PST) In-Reply-To: X-Original-Sender: lev@compuserve.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:31428 Archived-At: ------=_Part_672_1959060678.1488663613107 Content-Type: multipart/alternative; boundary="----=_Part_673_1957152851.1488663613107" ------=_Part_673_1957152851.1488663613107 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Yes, the variable templates would be a logical next step. There may be some= =20 additional issues with them, and I would very much prefer such issues not= =20 to be an impediment for the core idea. As to the spelling, in my view all= =20 upper case doesn't necessarily imply a macro but rather a constant=20 expression. I do not have a strong opinion in that regard however. On Saturday, March 4, 2017 at 4:18:14 PM UTC-5, Daniel Kr=C3=BCgler wrote: > > 2017-03-04 21:30 GMT+01:00 >:=20 > Given that we have variable templates now, why should the standard=20 > library provide these constants for a specific floating point type?=20 > Furthermore the UPPERCASE names look like macros, I would instead=20 > suggest to switch to a different spelling (I would be ok if only the=20 > first letter would be uppercase).=20 > > Depending on the outcome of CWG issue 1729, we could define pi as=20 > follows (in namespace std, not shown below, concrete values are just=20 > indicated):=20 > > template=20 > extern T pi;=20 > > template<>=20 > inline constexpr long double pi =3D 3.1415926535897932384...= L;=20 > > template<>=20 > inline constexpr double pi =3D 3.1415926535...;=20 > > template<>=20 > inline constexpr float pi =3D 3.141592...F;=20 > > - Daniel=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. To view this discussion on the web visit https://groups.google.com/a/isocpp= ..org/d/msgid/std-proposals/097e0a3f-275d-45e7-babb-d3f80e1fa83d%40isocpp.or= g. ------=_Part_673_1957152851.1488663613107 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
Yes, the variable templates would be a logical next step. = There may be some additional issues with them, and I would very much prefer= such issues not to be an impediment for the core idea. As to the spelling,= in my view all upper case doesn't necessarily imply a macro but rather= a constant expression. I do not have a strong opinion in that regard howev= er.

On Saturday, March 4, 2017 at 4:18:14 PM UTC-5, Daniel Kr=C3=BCg= ler wrote:
2017-03-04 21:30 GMT= +01:00 =C2=A0<l...@compuserve.com>:
Given that we have variable templates now, why should the standard
library provide these constants for a specific floating point type?
Furthermore the UPPERCASE names look like macros, I would instead
suggest to switch to a different spelling (I would be ok if only the
first letter would be uppercase).

Depending on the outcome of CWG issue 1729, we could define pi as
follows (in namespace std, not shown below, concrete values are just
indicated):

template<class T>
extern T pi;

template<>
inline constexpr long double pi<long double> =3D 3.14159265358979= 32384...L;

template<>
inline constexpr double pi<double> =3D 3.1415926535...;

template<>
inline constexpr float pi<float> =3D 3.141592...F;

- Daniel

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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.
To view this discussion on the web visit https://groups.google.= com/a/isocpp.org/d/msgid/std-proposals/097e0a3f-275d-45e7-babb-d3f80e1fa83d= %40isocpp.org.
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