220 31985 <665b5031-843b-4c30-8bb1-ced918c10656@isocpp.org> article Path: news.gmane.org!.POSTED!not-for-mail From: "T. C." Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: This variable should not be named: an identifier (not) to remember Date: Mon, 3 Apr 2017 13:28:56 -0700 (PDT) Lines: 102 Approved: news@gmane.org Message-ID: <665b5031-843b-4c30-8bb1-ced918c10656@isocpp.org> References: <985b9b2a-c734-45eb-95f4-db4dc0d309a1@isocpp.org> <1491170458.9U0G8TLsOk@tjmaciei-mobl1> <10c2c556-b6bb-4714-83bc-7b0ac8fd4143@isocpp.org> <1380e942-6c0c-4bae-9042-d3e5064e96d8@isocpp.org> <58E2A8A0.3010100@gmail.com> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_Part_961_1759207746.1491251336906" X-Trace: blaine.gmane.org 1491251338 15294 195.159.176.226 (3 Apr 2017 20:28:58 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Mon, 3 Apr 2017 20:28:58 +0000 (UTC) To: ISO C++ Standard - Future Proposals Original-X-From: std-proposals+bncBCQ43G7NQIIRBCPBRLDQKGQES5U7ILQ@isocpp.org Mon Apr 03 22:28:53 2017 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-yb0-f198.google.com ([209.85.213.198]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1cv8aq-0003Ui-J0 for gclcip-std-proposals@m.gmane.org; Mon, 03 Apr 2017 22:28:52 +0200 Original-Received: by mail-yb0-f198.google.com with SMTP id d76sf29393356ybh.18 for ; Mon, 03 Apr 2017 13:28:58 -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 :x-spam-checked-in-group:list-post:list-help:list-archive :list-subscribe:list-unsubscribe; bh=3p4VBGAvJ040A+RWEVTvm4T9+U+DkPcGeLRTy8myUqk=; b=FkQ9Ah/Jfb+3jsM/JCfqyGskzWxRdI8Xn+GTpRy5rUOE8hNp4kIHCZOe/ehuMM3u07 bnZP3GRqAqJzFp5WDFHNBd5zWeMNmS5eXv+pJlrTNu16DOSMKneSeGm2CmdK6j+WpUWz /JCYkU3Y9wVCgw8LqyHvsbgv2ba4pOXCMT8FQHzaHA05g1GJr7RsSAav0pgfZUsYM72e ZCnyBdBXpHgLtxAPrWCFFZmJ4bgrwV3E32AS/uhdkybMsb6LAjkY5kJVAvO38+gk8205 iVEpyUJ9qjXvq36S8xy+C6WdHnojPZx0/JolMVtOwZOprtwjqnGVGoOXrm2PgIjC3AzN QM4A== 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 :x-spam-checked-in-group:list-post:list-help:list-archive :list-subscribe:list-unsubscribe; bh=3p4VBGAvJ040A+RWEVTvm4T9+U+DkPcGeLRTy8myUqk=; b=H3A/nGpbWPQJFGaUW6RUkqvLnWpNXRH0EtXI/t+SSS4z2OwyMAm0JS/8ydCk7MGmgC ceU0hGZUp+x+X83qkdobvURmCM2A0PTpCYx6NBAL+ru7WxN42/ZdHWpBAHopqxXgqiJU Wy3vK32ATRZsvVuPiSZQCBo7xFRvVBJgsxcxOosqC0wiX+89Vb+UctYHZ5H784e7/56a tTziZemb14iLS1jdJwnh+0G9jd/Dwm3TAJBQgh+2YNbPK1v6qD7pgI31WFShKHgOOxiT sI5vWgneoAqOw2WBQ5O+8hc5zKe2KFsYXFNrzv+N4ULbSbWC83udbYCP6LkTEXeXX8r1 5mTw== 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=3p4VBGAvJ040A+RWEVTvm4T9+U+DkPcGeLRTy8myUqk=; b=l+O9opg994ChHaGmiMCYGQVRt7y0QVk1sPn4C0+iepQYI0WoiS7EZKEE4ek3nazIi2 vANGZEqr3gOYwhA/t+RD7vZiQcl7EDe+NLhEK6/l4fahiCHMKU0QJdXBt0tx4HguXpsJ nV59Xw1plaVR0UizPNrtlenjbZRtySJPfVcnhqGcMShQUQ0DUc2tPxRvWhESwLCEJupV NOfxGLGg9y644Ez53PqdX6meViswSdEGc7CuOx8ohIAmxCXOwwYfZ6mlc61YgGDGBeha lZWiKWDSEtw2BOS9bZ7VXI1hgUs1shgESd/RqAdc0xnQtmldlafXzIKvP9de4VaDZztF MZDg== X-Gm-Message-State: AFeK/H3mK3cAxmiUeesxHpCxIV8EE/RYUmxNvXzzoHq3YN5LFJC07NV5LDIlMwifMPBMjA== X-Received: by 10.129.82.133 with SMTP id g127mr7469385ywb.161.1491251338363; Mon, 03 Apr 2017 13:28:58 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.157.20.70 with SMTP id h64ls2127455oth.33.gmail; Mon, 03 Apr 2017 13:28:57 -0700 (PDT) X-Received: by 10.157.89.222 with SMTP id u30mr540831otg.7.1491251337479; Mon, 03 Apr 2017 13:28:57 -0700 (PDT) In-Reply-To: <58E2A8A0.3010100@gmail.com> X-Original-Sender: rs2740@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:31985 Archived-At: ------=_Part_961_1759207746.1491251336906 Content-Type: multipart/alternative; boundary="----=_Part_962_1813769586.1491251336907" ------=_Part_962_1813769586.1491251336907 Content-Type: text/plain; charset=UTF-8 On Monday, April 3, 2017 at 3:55:16 PM UTC-4, Matthew Woehlke wrote: > > On 2017-04-03 15:37, Barry Revzin wrote: > > I think the logical extreme of this idea is to not pick any identifier > at > > all - simply allow hiding declarations in the same scope. So from the > > original paper's examples, using __ to declare multiple variables in the > > same scope just works not because of some special magic bestowed upon > the > > identifier "__", but instead because you're actually declaring multiple > > variables in the same scope named "__". You'd have no way of accessing > the > > earlier versions of __, but then you don't want to anyway. I don't know > how > > to get the compiler to not warn against not using the last incarnation > of > > __ though. That just may be a "teach the compiler that this is a > convention > > that people want to use" kind of thing. > > That seems like a recipe for bugs. We have enough problems with -Wshadow > as it is, let alone making the situation *worse*... > > I think the original idea Richard posited is that there is no hiding. Instead, if you declare multiple variables with the same name in the same scope, you can't access *any* of them. Name lookup will simply find all the declarations and declare an ambiguity at that point. -- 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. To view this discussion on the web visit https://groups.google.com/a/isocpp.org/d/msgid/std-proposals/665b5031-843b-4c30-8bb1-ced918c10656%40isocpp.org. ------=_Part_962_1813769586.1491251336907 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable


On Monday, April 3, 2017 at 3:55:16 PM UTC-4, Matt= hew Woehlke wrote:
On 2017-04-0= 3 15:37, Barry Revzin wrote:
> I think the logical extreme of this idea is to not pick any identi= fier at=20
> all - simply allow hiding declarations in the same scope. So from = the=20
> original paper's examples, using __ to declare multiple variab= les in the=20
> same scope just works not because of some special magic bestowed u= pon the=20
> identifier "__", but instead because you're actually= declaring multiple=20
> variables in the same scope named "__". You'd have n= o way of accessing the=20
> earlier versions of __, but then you don't want to anyway. I d= on't know how=20
> to get the compiler to not warn against not using the last incarna= tion of=20
> __ though. That just may be a "teach the compiler that this i= s a convention=20
> that people want to use" kind of thing.=20

That seems like a recipe for bugs. We have enough problems with -Wshado= w
as it is, let alone making the situation *worse*...


I think the original idea Richard posi= ted is that there is no hiding. Instead, if you declare multiple variables = with the same name in the same scope, you can't access *any* of them. N= ame lookup will simply find all the declarations and declare an ambiguity a= t that point.

--
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/665b5031-843b-4c30-8bb1-ced918c10656= %40isocpp.org.
------=_Part_962_1813769586.1491251336907-- ------=_Part_961_1759207746.1491251336906-- .