220 40119 article Path: news.gmane.org!.POSTED!not-for-mail From: gmisocpp@gmail.com Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: enumerator duplicated value attribute Date: Sat, 8 Sep 2018 17:30:05 -0700 (PDT) Lines: 148 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_681_278034914.1536453006087" X-Trace: blaine.gmane.org 1536452882 7296 195.159.176.226 (9 Sep 2018 00:28:02 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Sun, 9 Sep 2018 00:28:02 +0000 (UTC) To: ISO C++ Standard - Future Proposals Original-X-From: std-proposals+bncBCM3TRNUXUDBBD6T2HOAKGQEM7PE64Y@isocpp.org Sun Sep 09 02:27:58 2018 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-yw1-f69.google.com ([209.85.161.69]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1fyna1-0001n7-Un for gclcip-std-proposals@m.gmane.org; Sun, 09 Sep 2018 02:27:58 +0200 Original-Received: by mail-yw1-f69.google.com with SMTP id d23-v6sf11462858ywb.2 for ; Sat, 08 Sep 2018 17:30:08 -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 :list-post:list-help:list-archive:list-subscribe:list-unsubscribe; bh=PdypavcROc4+/wApJ1q5RADqZyKNeV/6DtIUrXDHZdc=; b=V1aG2aDR9+Ol58qEEhHCzljMOURcpsSmptZqh6EIP3l2wwuLILhVG+fYhVlK9dhLAV 1xDEQSJjQ8xnhdwpXTIacHADL2O92NWH1ydn3J2u2vXFkJQjMf34szRFMCUysR048QEp XaM/DPfYoLCjcnhUDlEAVdPv0L8BEZ7/KuE5wwnCiYF27aA7iAyuEmyDSMgmvdJItv5V vFCxqMqraaQp3Rb0pyFnsmurf0SWo32vqiPqkLsTvvsJKSHC9fm2aa4VHYOML6m41i3Z kPjgnBwpFUCnjq+kbrltJCXurcnt5gyE5mjwqxrKiQH9sUHrFYuE3qrR+YX5V+heyEZx 1ktA== 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 :list-post:list-help:list-archive:list-subscribe:list-unsubscribe; bh=PdypavcROc4+/wApJ1q5RADqZyKNeV/6DtIUrXDHZdc=; b=rGgu+VLdm8AcFZe7ZLgD/i23tYdqC/r/n6z87LibvKzl5bhINVWby2YXig398fJfpI M9jihA6EoLO5OlPUFSMBOJbxdvoE7YsL83+2lN65shGmZhLbrOGjdUIpKNEMPgj1wA6e XaPJDeWlPXwJjnZ0U9NVKzV8mEvj24VDtQFkPzZCA2A6zO28TIvpacqSJ38sEwBSHmXd EswynzbpVZyfmIX7IjRVvbtkRLqsZ0RDuskEBqW0dWF/OasBAzK/K/4KUNj2jzY8Rm4d N/WO2rUFLvEc79qUD5tfQ3p3LymMSPst7AspB7qP3zk8TQHUYVrym5s+r2j1RMEX/vDf rEoQ== 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=PdypavcROc4+/wApJ1q5RADqZyKNeV/6DtIUrXDHZdc=; b=OoNNhgEJZT4zniX6Khc9Q0yKJmDppRbIfOAuPezMKsTnuLPF74alx0txkFq1Ir2F1q qN3eGdRIRnEFm3AyJAuFO1rU/7t6fUl+QFNWdgt3O4KhrdSibgbfA27W8VKpI/ir6Mx1 n2K7rY7+cxfVIHQJoJQUbUFVkiv1+IcfENe5ZTm9kx4Jhv02LJnL/dzVgWumjT2ov5Na IeSZKlW13LnPOK8ruBaaAVi4BctGZHv3VCqoPDbxPK816wDv+iEmVbeHnRc8+kqrj0w/ 2GQ0QxPV8EF7ja+hlby+AuzTOy/rCAEc3MbrXsCXYzjh5wwCbvoy14L93BQxc3lOizAg O7jw== X-Gm-Message-State: APzg51BpXrB8LrJJ4TUkwY3ylpi9xXeQ8Lw/6Py5ywi0XnilJl3ReHok L5acA9xxOOb4Z7OVjsQ+xCyNqw== X-Google-Smtp-Source: ANB0VdbDW+nZet5It9NtQf52j4SXWZj0+q4qMaJ3Y78ciGWWVvEVxL/7x3aIb9q9v8i92j3RZpbY/w== X-Received: by 2002:a25:410f:: with SMTP id o15-v6mr3428381yba.69.1536453008128; Sat, 08 Sep 2018 17:30:08 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 2002:a25:50f:: with SMTP id 15-v6ls795508ybf.17.gmail; Sat, 08 Sep 2018 17:30:06 -0700 (PDT) X-Received: by 2002:a25:ba44:: with SMTP id z4-v6mr133372ybj.7.1536453006829; Sat, 08 Sep 2018 17:30:06 -0700 (PDT) In-Reply-To: X-Original-Sender: gmisocpp@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:40119 Archived-At: ------=_Part_681_278034914.1536453006087 Content-Type: multipart/alternative; boundary="----=_Part_682_1969118459.1536453006088" ------=_Part_682_1969118459.1536453006088 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable I haven't ever had a need for this feature, but since clang supports a=20 warning for it, it seems it might be reasonable to have it as a standard=20 feature. Which is what the OP is asking for? So it's good you provided the information that there is a solution that=20 might work for his compiler, but would you vote for a standard way to do=20 this? I think that's the question. On Saturday, September 8, 2018 at 1:11:32 PM UTC+12, Arthur O'Dwyer wrote: > On Friday, September 7, 2018 at 11:55:57 AM UTC-7, Daniel Gutson wrote: >> >> Hi, >> >> sometimes is important to prevent duplication of enumerators in the= =20 >> enumerations. That's why some compilers such as clang has the=20 >> -Wduplicate-enum. >> However there are cases such as ranges within enums, where enumerators= =20 >> define a category and then are followed by the first element of the=20 >> category, with the same value. >> >> enum Ranges >> { >> CategoryX =3D 100, >> X1 =3D CategoryX, >> X2, >> X3 >> CategoryY =3D 200 >> // ... >> }; >> > > What Chris said: this code is already acceptable to Clang. > However, if you do ever run into a situation where Clang is giving you a= =20 > warning that is "usually correct but I don't want to see it in this=20 > particular case," there already exists markup to indicate that situation: > > enum Ranges { > CategoryX =3D 100, > X1 =3D CategoryX, > X2, > X3, > #pragma clang diagnostic push > #pragma clang diagnostic ignored "-Wduplicate-enum" > DeprecatedNameX1 =3D X1, > DeprecatedNameX2, > DeprecatedNameX3, > #pragma clang diagnostic pop > }; > > Unfortunately, Clang currently has what-I-consider-a-bug in that it=20 > requires you to put the pragma on the *first* occurrence of the value,=20 > rather than on the *duplicate* occurrence. I've filed a bug report=20 > . > > =E2=80=93Arthur > --=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/b6bee554-139b-4673-bbc2-a688a8a35e84%40isocpp.or= g. ------=_Part_682_1969118459.1536453006088 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
I haven't ever had a need for this=C2=A0feature, = but since clang supports a warning for it, it seems it might be reasonable = to have it as a standard feature. Which is what the OP is asking for?
=
So it's good you provided the information that there is a solution= that might work for his compiler, but would you vote for a standard way to= do this? I think=C2=A0that's the question.

On Saturday, Septemb= er 8, 2018 at 1:11:32 PM UTC+12, Arthur O'Dwyer wrote:
On Friday, September 7, 2018 at 11:55:57= AM UTC-7, Daniel Gutson wrote:
Hi,

=C2=A0 =C2=A0sometimes is important to prevent dup= lication of enumerators in the enumerations. That's why some compilers = such as clang has the -Wduplicate-enum.
However there are cases s= uch as ranges within enums, where enumerators define a category and then ar= e followed by the first element of the category, with the same value.
=

enum Ranges
{
=C2=A0 =C2=A0 Categor= yX =3D 100,
=C2=A0 =C2=A0 =C2=A0 =C2=A0X1 =3D CategoryX,
=C2=A0 =C2=A0 =C2=A0 =C2=A0X2,
=C2=A0 =C2=A0 =C2=A0 =C2=A0X3
=C2=A0 =C2=A0 =C2=A0CategoryY =3D 200
=C2=A0 =C2=A0 =C2= =A0 =C2=A0// ...
};

W= hat Chris said: this code is already acceptable to Clang.
However= , if you do ever run into a situation where Clang is giving you a warning t= hat is "usually correct but I don't want to see it in this particu= lar case," there already exists markup to indicate that situation:

enum Ranges {
=C2=A0 =C2=A0 CategoryX =3D 1= 00,
=C2=A0 =C2=A0 X1 =3D CategoryX,
=C2=A0 =C2=A0 X2,
=C2=A0 =C2=A0 X3,
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wduplicate-enum"
= =C2=A0 =C2=A0 DeprecatedNameX1 =3D X1,
=C2=A0 =C2=A0=C2=A0Depreca= tedNameX2,
=C2=A0 =C2=A0=C2=A0DeprecatedNameX3,
#pragma= clang diagnostic pop
};

Unfortunately, = Clang currently has what-I-consider-a-bug in that it requires you to put th= e pragma on the first occurrence of the value, rather than on the duplicate occurrence. I've filed a bug report.

=E2=80=93A= rthur

--
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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/b6bee554-139b-4673-bbc2-a688a8a35e84= %40isocpp.org.
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