220 4488 article Path: news.gmane.org!not-for-mail From: Ran Regev Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: using new keywords for more proposes Date: Thu, 23 May 2013 03:29:57 -0700 (PDT) Lines: 147 Approved: news@gmane.org Message-ID: References: Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_Part_505_4495646.1369304997834" X-Trace: ger.gmane.org 1369305000 23975 80.91.229.3 (23 May 2013 10:30:00 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Thu, 23 May 2013 10:30:00 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBDJMNP4X6UOBBJW766GAKGQECNGR5TI@isocpp.org Thu May 23 12:30:01 2013 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-ve0-f198.google.com ([209.85.128.198]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1UfSmV-0001LJ-W7 for gclcip-std-proposals@m.gmane.org; Thu, 23 May 2013 12:30:00 +0200 Original-Received: by mail-ve0-f198.google.com with SMTP id 15sf235229vea.9 for ; Thu, 23 May 2013 03:29:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=x-beenthere:date:from:to:message-id:in-reply-to:references:subject :mime-version:x-original-sender:reply-to:precedence:mailing-list :list-id:x-google-group-id:list-post:list-help:list-archive :list-subscribe:list-unsubscribe:content-type; bh=G5/pVCeTt2QE8ggNj3jpwuHl+w7IsBxLCsyqB8JrZWY=; b=tXoAYMzqOjLMcOwkSNBo2oR6TvOa4ozEc+xXVL7BuwphZSipusmgDCF1SsrWBmfzoS mbNh8eobKArZzJpsz/ypDZVVG9Smk13gMUj+sU5FsubeAf8Bl5LFPi2oghOgbPn9toZw OyDv7dpTwHtCt24hzenWbNIQ/iYABV3g09JehYGg+z26yBmceqhA+fJ4YYHqPOIqQYVj UTkYRcPYN2SL2henIXzWqqW4CvlTJl3JBhyQcRM7KNVCI1aGoEliHuET9T86Engyz1AK +4dYcpXq37I7Xc/nh+/VLLQnnnphIKYVWxdxR0Xyz6tfn32pN5W8EbeUP6eEuNT/l52f eg8g== X-Received: by 10.224.200.202 with SMTP id ex10mr6041823qab.8.1369304999003; Thu, 23 May 2013 03:29:59 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.49.18.195 with SMTP id y3ls1357029qed.67.gmail; Thu, 23 May 2013 03:29:58 -0700 (PDT) X-Received: by 10.49.1.197 with SMTP id 5mr1187093qeo.24.1369304998100; Thu, 23 May 2013 03:29:58 -0700 (PDT) In-Reply-To: X-Original-Sender: regev.ran@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:4488 Archived-At: ------=_Part_505_4495646.1369304997834 Content-Type: text/plain; charset=ISO-8859-1 Thanks for the answer, backward compatibility was my initial guess. I have two following questions: 1) Is it only me or that everyone must fix something when advancing a compiler? And if I'm not the only one, then what does it matter if we need to fix X issues or X + 3? 2) How do c++ editors color the new keywords? Do they try to understand the meaning of the words and color it accordingly, or ?? Ran. On Wednesday, May 22, 2013 9:52:21 AM UTC+3, James Dennett wrote: > > On Tue, May 21, 2013 at 11:31 PM, Ran Regev > > wrote: > > > > Hello, > > > > Can anyone point me to the discussion on "why not defining new keywords > as > > 'real' keywords"? > > It's discussed with almost horrible frequency, but mostly not in > writing in public forums I'd guess. > > The short version: it breaks existing code that uses them as > identifiers, and the C++ committee is (believe it or not) somewhat > strongly averse to breaking existing working code. > > (Personally I'd prefer to add more keywords; fixing up the resulting > problems is worthwhile in my opinion.) > > > For example, why can 'final' be used as a variable? > > Surely it causes problems: > > http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2013/n3539.html#1318 > > Breaking all of the code that uses "final" as an identifier would also > cause problems. As with almost all things, it's a trade-off, not a > good vs bad decision. (In my limited checks, there are actually far > more uses of "override" than "final", but both are used somewhat > frequently in real C++98 code.) > > In this particular case, there was pre-existing experience from > C++/CLI that using contextual keywords for these was workable -- and > the C++ committee does give some weight to implementation/usage > experience. > > You might notice that the keywords added in C++11 are often rather > obscure: e.g., "nullptr" instead of "null". A significant part of the > reason for that is to avoid clashes with existing code. > > -- James > -- --- 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. ------=_Part_505_4495646.1369304997834 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable

Thanks for the answer, backward compatibility was = my initial guess.
I have two following questions:
1) Is= it only me or that everyone must fix something when advancing a compiler?<= /div>
And if I'm not the only one, then what does it matter if we need = to fix X issues or X + 3?

2) How do c++ editors co= lor the new keywords? Do they try to understand the meaning of the words an= d color it accordingly, or ??

Ran.

On Wed= nesday, May 22, 2013 9:52:21 AM UTC+3, James Dennett wrote:
On Tue, May 21, 2013 at 11:31 PM, Ran Regev &l= t;rege...@gmail.com> wrote:
>
> Hello,
>
> Can anyone point me to the discussion on "why not defining new key= words as
> 'real' keywords"?

It's discussed with almost horrible frequency, but mostly not in
writing in public forums I'd guess.

The short version: it breaks existing code that uses them as
identifiers, and the C++ committee is (believe it or not) somewhat
strongly averse to breaking existing working code.

(Personally I'd prefer to add more keywords; fixing up the resulting
problems is worthwhile in my opinion.)

> For example, why can 'final' be used as a variable?
> Surely it causes problems:
> http://www.open-std.org/jtc1/sc22/= wg21/docs/papers/2013/n3539.html#1318

Breaking all of the code that uses "final" as an identifier would also
cause problems.  As with almost all things, it's a trade-off, not = a
good vs bad decision.  (In my limited checks, there are actually f= ar
more uses of "override" than "final", but both are used somewhat
frequently in real C++98 code.)

In this particular case, there was pre-existing experience from
C++/CLI that using contextual keywords for these was workable -- and
the C++ committee does give some weight to implementation/usage
experience.

You might notice that the keywords added in C++11 are often rather
obscure: e.g., "nullptr" instead of "null".  A significant part of= the
reason for that is to avoid clashes with existing code.

-- James

--
 
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