220 31930 article Path: news.gmane.org!.POSTED!not-for-mail From: Richard Smith Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: This variable should not be named: an identifier (not) to remember Date: Sun, 2 Apr 2017 13:10:14 -0700 Lines: 114 Approved: news@gmane.org Message-ID: References: <985b9b2a-c734-45eb-95f4-db4dc0d309a1@isocpp.org> <1491170458.9U0G8TLsOk@tjmaciei-mobl1> <170CB823-B63F-4910-A227-95C23314ADAD@gmail.com> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: multipart/alternative; boundary=f403045cf79abbadda054c34a220 X-Trace: blaine.gmane.org 1491163836 8259 195.159.176.226 (2 Apr 2017 20:10:36 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Sun, 2 Apr 2017 20:10:36 +0000 (UTC) To: "std-proposals@isocpp.org" Original-X-From: std-proposals+bncBDVNBJG4YAIBBPFVQXDQKGQEQMD36QI@isocpp.org Sun Apr 02 22:10:32 2017 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-lf0-f72.google.com ([209.85.215.72]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1culpX-0001ap-M3 for gclcip-std-proposals@m.gmane.org; Sun, 02 Apr 2017 22:10:31 +0200 Original-Received: by mail-lf0-f72.google.com with SMTP id x137sf24411735lff.3 for ; Sun, 02 Apr 2017 13:10:37 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:sender:in-reply-to:references:from :date:message-id:subject:to:x-original-sender :x-original-authentication-results:reply-to:precedence:mailing-list :list-id:x-spam-checked-in-group:list-post:list-help:list-archive :list-subscribe:list-unsubscribe; bh=1O42HEE1rb2ub9Kwl9Z075yaWDlElmLswl0Pkr4RnKI=; b=Wj5FvrY2g9j3VgrHl93MSTahicywx1A5U31wnpvB1JIsFJEo/+IaegTVrc2hgZ06Vc SCd9v/VifQFnXzVaLUglRlwQ1CxC9/eZyPQ6jVhPlRpY9GeTm9wccgenKCmxdS9vsqYh KCoFvCG8fKpT8B5NIHelcPf/srMlen5RJD4u/xy00pTz8bgLTg6EYdpjQ1NesGrp9cpZ YxXwtBTMBDyayg1X1KtqK6tB6v6cuaJCE8EFdjPVmf1N8s62qlyxry2YzFyuVFHrUHrG +Kt739tuFiWMPpDrPnLbyRnFGQKhpRW2x/h+R7G8IOK9RZdRATDHlY0sQo0WG8eo+a9r zzAQ== X-Gm-Message-State: AFeK/H2rHil4X31VRGIDdYzRmgWYkFHw3+Rax/7KmKb5AiclbQlzE0C8NFX5e1mOQF3EYA== X-Received: by 10.25.235.21 with SMTP id j21mr1810658lfh.10.1491163837765; Sun, 02 Apr 2017 13:10:37 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.28.184.4 with SMTP id i4ls556779wmf.21.gmail; Sun, 02 Apr 2017 13:10:36 -0700 (PDT) X-Received: by 10.28.195.214 with SMTP id t205mr6356582wmf.104.1491163836313; Sun, 02 Apr 2017 13:10:36 -0700 (PDT) Original-Received: from mail-wr0-x230.google.com (mail-wr0-x230.google.com. [2a00:1450:400c:c0c::230]) by mx.google.com with ESMTPS id e2si17044233wrc.122.2017.04.02.13.10.36 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sun, 02 Apr 2017 13:10:36 -0700 (PDT) Received-SPF: pass (google.com: domain of metafoo@gmail.com designates 2a00:1450:400c:c0c::230 as permitted sender) client-ip=2a00:1450:400c:c0c::230; Original-Received: by mail-wr0-x230.google.com with SMTP id w43so142462242wrb.0 for ; Sun, 02 Apr 2017 13:10:36 -0700 (PDT) X-Received: by 10.223.178.182 with SMTP id g51mr11531392wrd.12.1491163835770; Sun, 02 Apr 2017 13:10:35 -0700 (PDT) Original-Sender: metafoo@gmail.com Original-Received: by 10.80.148.82 with HTTP; Sun, 2 Apr 2017 13:10:14 -0700 (PDT) In-Reply-To: <170CB823-B63F-4910-A227-95C23314ADAD@gmail.com> X-Original-Sender: richard@metafoo.co.uk X-Original-Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com; spf=pass (google.com: domain of metafoo@gmail.com designates 2a00:1450:400c:c0c::230 as permitted sender) smtp.mailfrom=metafoo@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:31930 Archived-At: --f403045cf79abbadda054c34a220 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On 2 April 2017 at 12:56, Alberto Barbati wrote: > Il giorno 02 apr 2017, alle ore 20:03, Thiago Macieira < > thiago@macieira.org> ha scritto: > > >> On s=C3=A1bado, 1 de abril de 2017 21:19:37 PDT Richard Smith wrote: > >> Have you considered that possibility? It would give a better name (_ > rather > >> than __) and avoid "breaking" existing code that uses __. > > > > _ is not reserved to the compiler and is VERY often #defined to gettext= .. > > Thank you Richard for your suggestion which is very interesting, since it > provides good insights about a possible wording. As for the name, I belie= ve > Thiago and Magnus raised valid concerns, though. It's true that the we > might choose _ without breaking existing code. However defining _ as a > macro is currently valid and apparently widely used. I believe we therefo= re > have only two choices: either we make such uses undefined behavior > (upsetting a lot of people) or we choose wording to avoid that (making th= e > feature essentially unusable for users of all libraries like gettext). No= ne > of the two approaches seems very good. Is there a third option? > As noted, gettext defines _ as a function-like macro, so there seems to be no technical problem for users of gettext (although some might consider overloading the meaning of _ in this way to be a readability problem). __ seems somewhat safer and less controversial. I would expect you'll find controversy if you pick a worse name in order to avoid collision with a macro name that some would already consider to be poorly chosen, so I don't think it's clear which will be less controversial= .. --=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/CAOfiQqkRjs1jkgVrXLM8HA%2BXbkTJQ8oBoZh9XneTPCgB4= AK7GQ%40mail.gmail.com. --f403045cf79abbadda054c34a220 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
On 2= April 2017 at 12:56, Alberto Barbati <albertobarbati@gmail.com= > wrote:
Il giorno 02 apr= 2017, alle ore 20:03, Thiago Macieira <thiago@macieira.org> ha scritto:

>> On s=C3=A1bado, 1 de abril de 2017 21:19:37 PDT Richard Smith wrot= e:
>> Have you considered that possibility? It would give a better name = (_ rather
>> than __) and avoid "breaking" existing code that uses __= ..
>
> _ is not reserved to the compiler and is VERY often #defined to gettex= t.

Thank you Richard for your suggestion which is very interesting, sin= ce it provides good insights about a possible wording. As for the name, I b= elieve Thiago and Magnus raised valid concerns, though. It's true that = the we might choose _ without breaking existing code. However defining _ as= a macro is currently valid and apparently widely used. I believe we theref= ore have only two choices: either we make such uses undefined behavior (ups= etting a lot of people) or we choose wording to avoid that (making the feat= ure essentially unusable for users of all libraries like gettext). None of = the two approaches seems very good. Is there a third option?

As noted, gettext defines _ as a function-like macro,= so there seems to be no technical problem for users of gettext (although s= ome might consider overloading the meaning of _ in this way to be a readabi= lity problem).

__ seems somewhat safer and less controversial.

=
I would expect you'll find controversy if you pick a worse name in= order to avoid collision with a macro name that some would already conside= r to be poorly chosen, so I don't think it's clear which will be le= ss controversial.

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