220 33519 <34130636.8iyeqGTS6R@tjmaciei-mobl1> article Path: news.gmane.org!.POSTED!not-for-mail From: Thiago Macieira Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: A more advanced switch Date: Tue, 01 Aug 2017 14:34:23 -0700 Lines: 58 Approved: news@gmane.org Message-ID: <34130636.8iyeqGTS6R@tjmaciei-mobl1> References: Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Trace: blaine.gmane.org 1501623270 8754 195.159.176.226 (1 Aug 2017 21:34:30 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Tue, 1 Aug 2017 21:34:30 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBCB4TK757YBRBY7HQPGAKGQE7HMDNEI@isocpp.org Tue Aug 01 23:34:26 2017 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-pf0-f198.google.com ([209.85.192.198]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1dceo2-0001tj-Tj for gclcip-std-proposals@m.gmane.org; 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[78.47.120.188]) by mx.google.com with ESMTP id v130si2783732itv.196.2017.08.01.14.34.26 for ; Tue, 01 Aug 2017 14:34:26 -0700 (PDT) Received-SPF: pass (google.com: domain of thiago@macieira.org designates 78.47.120.188 as permitted sender) client-ip=78.47.120.188; Original-Received: from tjmaciei-mobl1.localnet (unknown [134.134.139.82]) by gondolin.macieira.info (Postfix) with ESMTPSA id 6F49711B5B8 for ; Tue, 1 Aug 2017 14:34:25 -0700 (PDT) In-Reply-To: X-Original-Sender: thiago@macieira.org X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of thiago@macieira.org designates 78.47.120.188 as permitted sender) smtp.mailfrom=thiago@macieira.org 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:33519 Archived-At: On ter=C3=A7a-feira, 1 de agosto de 2017 14:24:04 PDT costelnistor12@gmail.= com=20 wrote: > We have to use "case" for every, well, case when specifying a sequence, > because it uses fallthrough. We have to use "break" to avoid that. I find > this bad. Because of the necessity of using "break" we can't just "break" > out of a loop if the switch is inside a loop. Also, if there are > consecutive cases we have to specify each one of them. Additionally, we > could also forget breaking. This "switch" isn't safe and is pretty old. >=20 > In Pawn we can do it a lot better: > switch( variable ) > { > case 0 .. 4: With GNU extensions to C and C++: case 0 ... 4: > 1. There's no need for break, there's no fallthrough. Advantage: we can > easily "continue" and "break" loops from inside the "switch". That can't change now. This HAS been discussed in this list and in std- discussions and, just like the non-local breaks, it's very hard to adapt th= e=20 language grammar to. We need a different keyword or some modification keyword to the switch, sin= ce=20 there is unmarked code that expects to fall through. We cannot silently bre= ak=20 them. > I know that it's hard to have features accepted in such a popular standar= d, > but upgrading switch is something that should really be considered ! > C++17's [[fallthrough]] attribute is just as complicated as the "switch". > It needs to be added everywhere or else we would get warnings (AFAIK). We've done that in Qt. Not very difficult once the compiler starts warning. The difficult part is to guess whether a fallthrough was intended or a brea= k was=20 missing. --=20 Thiago Macieira - thiago (AT) macieira.info - thiago (AT) kde.org Software Architect - Intel Open Source Technology Center --=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/34130636.8iyeqGTS6R%40tjmaciei-mobl1. .