220 4249 article Path: news.gmane.org!not-for-mail From: Tony V E Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Fixing Standard Library relational operators (was: Re: optional Rev.4 (N3672): What was the rationale to remove !=, >=, ...) Date: Fri, 3 May 2013 15:45:38 -0400 Lines: 156 Approved: news@gmane.org Message-ID: References: <5f236e41-0f5f-4288-a80f-9eadb5168c38@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: multipart/alternative; boundary=001a11c34a3a79194504dbd59811 X-Trace: ger.gmane.org 1367610344 2855 80.91.229.3 (3 May 2013 19:45:44 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Fri, 3 May 2013 19:45:44 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBCUZ5QWKNQIOLJ4QRQCRUBEHQRXDO@isocpp.org Fri May 03 21:45:43 2013 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-fa0-f70.google.com ([209.85.161.70]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1UYLvK-0000nN-Ie for gclcip-std-proposals@m.gmane.org; Fri, 03 May 2013 21:45:42 +0200 Original-Received: by mail-fa0-f70.google.com with SMTP id a11sf3134537fad.1 for ; Fri, 03 May 2013 12:45:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=x-received:x-beenthere:x-received:received-spf:mime-version :x-received:in-reply-to:references:date:message-id:subject:from:to :x-original-sender:x-original-authentication-results:reply-to :precedence:mailing-list:list-id:x-google-group-id:list-post :list-help:list-archive:list-subscribe:list-unsubscribe:content-type; bh=w+o9XBn6EReqPHY0ILH+5g1aWNBB0TWO0aoUk3pG1j0=; b=PkOBC0oadZzWG5rjhSXsFgP/ucGt33Uehcd5cyys0o4snEjlC/lo/ZB7xBEY7dqp1D GDxUv60kSkXQmKF76Jb+F+Nkc5LTFZ4YGsESW093Sna/mh/7m559BrYnBUuNvq4yVpTy Wp6AV1uBPNdLyV5nT37ZgtN2otkSkRihDSq/0bRccdtG2g9u7rjDYDDy4c9SwdZCXcU5 KF788WQuN6oii+5XYFrc16E4BPw38eTbBo5dxBhHLBygZD/OwftRyn7Sm0vpyWoL1ebT zkY/pbDzy3fAM6T3k56NYJbFrMW30aBE/CF9vZo9b3AtMczwkUgp0lKM2BV39JkbJoGh X-Received: by 10.112.145.196 with SMTP id sw4mr13332396lbb.5.1367610341775; Fri, 03 May 2013 12:45:41 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.152.129.197 with SMTP id ny5ls166910lab.26.gmail; Fri, 03 May 2013 12:45:39 -0700 (PDT) X-Received: by 10.112.130.40 with SMTP id ob8mr4773407lbb.55.1367610339595; Fri, 03 May 2013 12:45:39 -0700 (PDT) Original-Received: from mail-lb0-f172.google.com (mail-lb0-f172.google.com [209.85.217.172]) by mx.google.com with ESMTPS id s5si2457192las.239.2013.05.03.12.45.39 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Fri, 03 May 2013 12:45:39 -0700 (PDT) Received-SPF: pass (google.com: domain of tvaneerd@gmail.com designates 209.85.217.172 as permitted sender) client-ip=209.85.217.172; Original-Received: by mail-lb0-f172.google.com with SMTP id y6so1880900lbh.31 for ; Fri, 03 May 2013 12:45:39 -0700 (PDT) X-Received: by 10.112.72.163 with SMTP id e3mr796415lbv.28.1367610339430; Fri, 03 May 2013 12:45:39 -0700 (PDT) Original-Received: by 10.112.2.167 with HTTP; Fri, 3 May 2013 12:45:38 -0700 (PDT) In-Reply-To: X-Original-Sender: tvaneerd@gmail.com X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of tvaneerd@gmail.com designates 209.85.217.172 as permitted sender) smtp.mail=tvaneerd@gmail.com; dkim=pass header.i=@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:4249 Archived-At: --001a11c34a3a79194504dbd59811 Content-Type: text/plain; charset=ISO-8859-1 On Fri, May 3, 2013 at 2:12 PM, Ville Voutilainen < ville.voutilainen@gmail.com> wrote: > > > > On 3 May 2013 20:55, Marc wrote: > >> >> But why should I, as someone using a non total order, have to specialize >> anything? If the underlying type has operator>, then optional should use it >> for >. If it doesn't, then optional shouldn't either. If you are using >> rel_ops with T, you can just as well use rel_ops with optional. >> >> >> > Currently tuple, pair and containers don't do that. It would be reasonable > to be consistent in that regard > with optional, and consider further changes separately afterwards. > > > > You know that we will never change tuple, unless we can somehow come up with a backwards compatible change (ie generate > only if not defined by underlying type - that would at least break *less* people). I don't understand the importance of consistency with tuple. You currently cannot do tuple() < int() You *can* do optional() < int() Mixed relops are part of "optional acts like T with one more value". If you must pick "consistency" then consistency with T is more important than consistency with tuple. There really isn't much analogy between tuple and optional. Yes they are both templated structs. The End. I find tuple<> more like a cheap struct, like the classic EmployeeRecord struct. And it doesn't bother me that EmployeeRecord isn't sorted exactly like its members, so I can live with tuple<> not sorting like its members. (still bothers me, but I can live with it) When will *any* code get a surprising result because optional works differently than tuple? There *will* be code that is surprised that optional ordered T differently than T did. Not much code, but some. The opening paragraphs of the optional proposal described a number of mental models for optinoal<> and chose "T with one more value". If that is the model, then acting like T is more important than acting like tuple. Tony -- --- 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. Visit this group at http://groups.google.com/a/isocpp.org/group/std-proposals/?hl=en. --001a11c34a3a79194504dbd59811 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable



On Fri, May 3, 2013 at 2:12 PM, Ville Voutilainen <ville= ..voutilainen@gmail.com> wrote:



On 3 May= 2013 20:55, Marc <marc.glisse@gmail.com> wrote:

But why should I= , as someone using a non total order, have to specialize anything? If the u= nderlying type has operator>, then optional should use it for >. If i= t doesn't, then optional shouldn't either. If=A0 you are using rel_= ops with T, you can just as well use rel_ops with optional<T>.



Currently tuple,= pair and containers don't do that. It would be reasonable to be consis= tent in that regard
with optional, and consider further changes separate= ly afterwards.




You know that we will = never change tuple, unless we can somehow come up with a backwards compatib= le change (ie generate > only if not defined by underlying type - that w= ould at least break *less* people).


I don't understand the importance of consistency wit= h tuple.

You currently cannot do

tuple<int>(= )=A0 <=A0 int()


You *can* do

opt= ional<int>()=A0=A0 <=A0 int()


Mixed relops are part of "optional acts like T with= one more value".

If you must pick "consistency= " then consistency with T is more important than consistency with tupl= e.=A0 There really isn't much analogy between tuple and optional.=A0 Ye= s they are both templated structs.=A0 The End.

I=20 find tuple<> more like a cheap struct, like the classic=20 EmployeeRecord struct.=A0 And it doesn't bother me that EmployeeRecord= =20 isn't sorted exactly like its members, so I can live with tuple<>= =20 not sorting like its members.=A0 (still bothers me, but I can live with=20 it)


When will *any* code get a surprising result because optiona= l works differently than tuple?
There *will* be code that is = surprised that optional ordered T differently than T did.=A0 Not much code,= but some.


The opening paragraphs of the optional proposal describe= d a number of mental models for optinoal<> and chose "T with one= more value".=A0 If that is the model, then acting like T is more impo= rtant than acting like tuple.

Tony

=A0

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