220 4475 article Path: news.gmane.org!not-for-mail From: James Dennett Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: using new keywords for more proposes Date: Tue, 21 May 2013 23:52:21 -0700 Lines: 48 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: text/plain; charset=ISO-8859-1 X-Trace: ger.gmane.org 1369205545 28090 80.91.229.3 (22 May 2013 06:52:25 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Wed, 22 May 2013 06:52:25 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBD3JZ2GYRAKRBJWW6GGAKGQENCUFFSA@isocpp.org Wed May 22 08:52:27 2013 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-oa0-f69.google.com ([209.85.219.69]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1Uf2uO-0008OE-Bz for gclcip-std-proposals@m.gmane.org; Wed, 22 May 2013 08:52:24 +0200 Original-Received: by mail-oa0-f69.google.com with SMTP id i10sf8369233oag.0 for ; Tue, 21 May 2013 23:52:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20120113; h=x-beenthere:mime-version: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=BURISbDzVSvlUlmOPhWia2lr0DRI1U2CEzFEcd3xgLo=; b=gPahT464m6tOCtDb2sRlzJPVNIlC0ufLrHa/LOCGRsR/IYt5vQbMvYaVbxihRDZ5+r US9R3vY9/bJqc2YVOshmEdtvM8fJ083QMW91VkhBQBQvLNtEqren3g5S6vt9SfsFMJ2O /icoTJjf70VD+yqtZUSWB0/Z4p62sQN0MveppLh1uVrEQ6jvJ7/QhNYH0TR38oNhq+i/ 6wUtM6AbWjsJWstG5IN3s5e6Lv97ozMDOmwy+Qj+k9+ovHcd3n2m/mbIUrWxKZPsvUcg aOd6miQOzRkffk4SyjGQAE/qRJtni0llqWiPWM7h5HayJRUqo332zgU5xyGRodoWH5rY 3Rww== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20120113; h=x-beenthere:mime-version:in-reply-to:references:date:message-id :subject:from:to:x-gm-message-state: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=BURISbDzVSvlUlmOPhWia2lr0DRI1U2CEzFEcd3xgLo=; b=YJ58fX1nzZJvd9phlmC/J10svvHRq2uCE61mdh7tqp1HTtpKs7Ga9mIiZ+XMy11k16 LxjrePYCBE6BBwDPSnXgHNyS5mTSv74GoC9rjbMo7tqgxR945sj/uencugr0zg9Ts23e 8abukC9BlXKdAUuEbDYJpv+ckL/q3l1EE7QePrL51xc1B77fQqEeVHvdSEeOQ8KU4IkM qkHJrr7V4w3Z1CBx/iblQhoX4oVbZqhi89CYfdqc382yU0lsCP2AF3ajH4oVAg41+dAu GfSKvVVfwD0c3XcGNBCfJhLCY7CJV/T9JR3ZsMjBH75R/U6ZlCDeO2pqNgBrHu+u8/ss t1EA== X-Received: by 10.182.236.231 with SMTP id ux7mr1863697obc.5.1369205543311; Tue, 21 May 2013 23:52:23 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.182.24.201 with SMTP id w9ls209438obf.49.gmail; Tue, 21 May 2013 23:52:22 -0700 (PDT) X-Received: by 10.60.84.102 with SMTP id x6mr3828253oey.73.1369205542186; Tue, 21 May 2013 23:52:22 -0700 (PDT) Original-Received: from mail-ie0-x22f.google.com (mail-ie0-x22f.google.com [2607:f8b0:4001:c03::22f]) by mx.google.com with ESMTPS id do5si3651826oeb.27.2013.05.21.23.52.22 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Tue, 21 May 2013 23:52:22 -0700 (PDT) Received-SPF: pass (google.com: domain of jdennett@google.com designates 2607:f8b0:4001:c03::22f as permitted sender) client-ip=2607:f8b0:4001:c03::22f; Original-Received: by mail-ie0-f175.google.com with SMTP id s9so4297955iec.6 for ; Tue, 21 May 2013 23:52:21 -0700 (PDT) X-Received: by 10.42.155.202 with SMTP id v10mr3306099icw.2.1369205541752; Tue, 21 May 2013 23:52:21 -0700 (PDT) Original-Received: by 10.231.15.69 with HTTP; Tue, 21 May 2013 23:52:21 -0700 (PDT) In-Reply-To: X-Gm-Message-State: ALoCoQmQkK+kPofO6CEGsH3T/mi/779ez5FIxpU1wg9Iz2Mn+wAXgQVgb9Sr9ixWuOG+KFGWJsA4Yr1UHGRfcWqOzKmO8VB7VeFkW6UDNRjSyxnAuspYluW0oUiZ99YJaWA/sj2VqcQMobKfQ1VgWgZjPZCly3oJftR1EdvrO0CImKS1uJtS97vQ+4GoLR0xIfuMI4weosIG X-Original-Sender: jdennett@google.com X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of jdennett@google.com designates 2607:f8b0:4001:c03::22f as permitted sender) smtp.mail=jdennett@google.com; dkim=pass header.i=@google.com; dmarc=pass (p=REJECT dis=none) d=google.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:4475 Archived-At: 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. .