220 22277 article Path: news.gmane.org!not-for-mail From: Morwenn Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Thoughts about P0100R0 Date: Thu, 5 Nov 2015 14:17:46 -0800 (PST) Lines: 91 Approved: news@gmane.org Message-ID: Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_Part_993_370600272.1446761866902" X-Trace: ger.gmane.org 1446761871 29971 80.91.229.3 (5 Nov 2015 22:17:51 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Thu, 5 Nov 2015 22:17:51 +0000 (UTC) To: ISO C++ Standard - Future Proposals Original-X-From: std-proposals+bncBC2ZP4V74IFBBDFL56YQKGQEZWEN77Q@isocpp.org Thu Nov 05 23:17:50 2015 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-ig0-f198.google.com ([209.85.213.198]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1ZuSqr-0006oS-9t for gclcip-std-proposals@m.gmane.org; Thu, 05 Nov 2015 23:17:49 +0100 Original-Received: by igcui1 with SMTP id ui1sf61593617igc.2 for ; Thu, 05 Nov 2015 14:17:48 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=date:from:to:message-id:subject:mime-version:content-type :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=x7urZHTcR/OIVyfr2Uh0I3f/Iv/kY5UkmISwiU+Fv8Y=; b=EBuzt/pT+9l4wWVHxUVvR0FrnjFMpjCdVBz/VmQaS3D0Q4TNB5dtU5GWFFZSGBAAVg I9xs5hVUY8KiLNvIrJBQeAIkotn8hwZB5Tx8qYH/PGIavx+mbVc/iYlLy+DHJjVW1+LE 0JAIZHsp5sqNEHW5+sRdo8drOWQyEWIRNG0k1HcfWYjH+9H1nQk3TV+10qdB/x29vKOm uj+r+k8Pdh1e3O2QZIGkS/2s4WtQW+m21QnAt/tBSFlGw6g2Ov7TcMVl57kfiVzgmV5T UxNC0As/n2KPMX0jm4iGwdS2Yc7Ce1dBPEszdv0Mjne0bMPpIJJ2guYKVHsLakNy5rxu WdYA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:date:from:to:message-id:subject:mime-version :content-type: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=x7urZHTcR/OIVyfr2Uh0I3f/Iv/kY5UkmISwiU+Fv8Y=; b=RyQdHnYNPmPlLvZ8902LYWNoI7ggXhWqgwpmniePWdoqN58Y6ID1n3oHU21iOXeBgp N/tkifMB7XFlp20ndJcrKeEZiAQJM+t4TcQSBrurqEi4lTwUYciyedXY9LvH7WEOQHmx xYEVSA9jndk+B4Ag1xra4Eufgj78+zhUXks2L1iWeQjGvFajXOe0rHh4cJRlYHt7b33C GReZgdSIE+MybvniXdnoSfEBH3icAuZ47SXRPTIxFriYsQfSAK/2/h8FPOwPBKxzMWQ/ o1HEqgTkDIMPdyh+UhwWl+WHVGFjx8XeLFykFvTApElhnsSstnyIkD4KAzCy0XR6Ed/k Z0Kg== X-Gm-Message-State: ALoCoQl7qrSbH6vFevGiAitsTNs5QzZuYl0godJFqw+WrHKQb79FPKJF4aNPeevSj2dD9BrwVTQn X-Received: by 10.182.226.195 with SMTP id ru3mr8322727obc.12.1446761868555; Thu, 05 Nov 2015 14:17:48 -0800 (PST) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.50.61.135 with SMTP id p7ls285905igr.14.canary; Thu, 05 Nov 2015 14:17:47 -0800 (PST) X-Received: by 10.50.3.41 with SMTP id 9mr158368igz.7.1446761867946; Thu, 05 Nov 2015 14:17:47 -0800 (PST) X-Original-Sender: morwenn29@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:22277 Archived-At: ------=_Part_993_370600272.1446761866902 Content-Type: multipart/alternative; boundary="----=_Part_994_2086772886.1446761866902" ------=_Part_994_2086772886.1446761866902 Content-Type: text/plain; charset=UTF-8 Among other things, P0100R0 proposes to add the following strongly-typed enumerations to the standard library: enum class partial_ordering { less, unordered, greater }; enum class weak_ordering { less, equivalent, greater }; enum class total_ordering { less, equal, greater }; I think that the idea is great but that these enumerations would benefit from an explicit conversion to int where the three values would be equal to -1, 0 and 1. It would allow to have strong typing by default but the ability to interface with old APIs that rely on the values -1, 0 and 1. While some of this old APIs only check the values, other ones do some arithmetic with the returned values (I have seen multiplications, but also additions in the wild) and changing every API would be a bit bothersome. Basically, I propose to change the enumerations as follows: enum class partial_ordering: int { less = -1, unordered = 0, greater = 1 }; enum class weak_ordering: int { less = -1, equivalent = 0, greater = 1 }; enum class total_ordering: int { less = -1, equal = 0, greater = 1 }; Any opinion about that? Morwenn. -- --- 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. 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Among other things, P0100R0 proposes to add the following = strongly-typed enumerations to the standard library:

en=
um class partial_ordering { less, unordered, greater };
enum class weak_ordering { less, equivalent, greater };
enum class total_ordering { less, equal, greater };
I think that the idea is great but that these enumerations would ben=
efit from an explicit conversion to int where the three values would be equ=
al to -1, 0 and 1.
It would allow to have strong typing by default but t=
he ability to interface with old APIs that rely on the values -1, 0 and 1. =
While some of this old APIs only check the values, other ones do some arith=
metic with the returned values (I have seen multiplications, but also addit=
ions in the wild) and changing every API would be a bit bothersome.

=
Basically, I propose to change the enumerations as follows:

enu=
m class partial_ordering: int { less =3D -1, unordered =3D 0, greater =3D 1=
 };
enum class weak_ordering: int { less =3D -1, equivalent =3D 0, greater =3D =
1 };
enum class total_ordering: int { less =3D -1, equal =3D 0, greater =3D 1 };=


Any opinion about that?

Morwe=
nn.

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