220 5915 <521DAAF4.3050100@beamways.com> article Path: news.gmane.org!not-for-mail From: Bengt Gustafsson Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Re: Properties Syntax Date: Wed, 28 Aug 2013 09:47:00 +0200 Lines: 65 Approved: news@gmane.org Message-ID: <521DAAF4.3050100@beamways.com> References: <5e23a0e9-2bd9-4f62-aa83-47bea8144eae@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: quoted-printable X-Trace: ger.gmane.org 1377676014 23434 80.91.229.3 (28 Aug 2013 07:46:54 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Wed, 28 Aug 2013 07:46:54 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBCRIRSPDTQIRB36V62IAKGQEVOEFFHI@isocpp.org Wed Aug 28 09:46:56 2013 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-ee0-f70.google.com ([74.125.83.70]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1VEaSu-0005Re-9j for gclcip-std-proposals@m.gmane.org; Wed, 28 Aug 2013 09:46:56 +0200 Original-Received: by mail-ee0-f70.google.com with SMTP id b15sf6122698eek.1 for ; Wed, 28 Aug 2013 00:46:55 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20120113; h=message-id:date:from:user-agent:mime-version:to:subject:references :in-reply-to:x-original-sender:x-original-authentication-results :reply-to:precedence:mailing-list:list-id:list-post:list-help :list-archive:list-subscribe:list-unsubscribe:content-type :content-transfer-encoding; bh=pnrzVjk1JETSpU4OwK9IUB7+zGMhkCh67O9n9qFYTq8=; b=Snrlwperi+2P00YE1+expTKxQ2ddOY+mDh6iUZn5am2s9PnjPtGK2sa69kxfo8x8xY Mus38C1sMc7jF3VPCOgqTPD+9n2x02fxMrjzckdDsVP03ZMqgz3Ba041TXmmGkzUwtdp EqMaEcwwmDGi27+P+Tp4ENB632fYPYf4ygY6v4nO61eKi96m9guB/QZxDsXyBEy+EM4b GQfwL+R88R8/E8BciCCbnwiRZVxzYEzrMRbYwAY/D+Lg+5G93WuSB4vPgGYW86zyjQS5 voPz3ONZB05LAf77/phfbSZbZrf+Qw53z3+OiVt2hJKE2QO/r06Epj5ZvJ59BJoJ3u9E I+cQ== X-Received: by 10.112.11.20 with SMTP id m20mr5707023lbb.4.1377676015310; Wed, 28 Aug 2013 00:46:55 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.152.120.199 with SMTP id le7ls12958lab.77.gmail; Wed, 28 Aug 2013 00:46:54 -0700 (PDT) X-Received: by 10.112.42.68 with SMTP id m4mr21213815lbl.4.1377676014710; Wed, 28 Aug 2013 00:46:54 -0700 (PDT) Original-Received: from vsp02.s.thehostingplatform.com (vsp02.s.thehostingplatform.com. [213.180.89.90]) by mx.google.com with ESMTPS id i6si4947430lah.161.1969.12.31.16.00.00 (version=TLSv1 cipher=RC4-SHA bits=128/128); Wed, 28 Aug 2013 00:46:54 -0700 (PDT) Received-SPF: neutral (google.com: 213.180.89.90 is neither permitted nor denied by best guess record for domain of bengt.gustafsson@beamways.com) client-ip=213.180.89.90; Original-Received: from [192.168.1.68] (unknown [85.229.130.195]) by vsp02.s.thehostingplatform.com (Halon Mail Gateway) with ESMTPSA for ; Wed, 28 Aug 2013 09:46:52 +0200 (CEST) User-Agent: Mozilla/5.0 (Windows NT 6.2; WOW64; rv:17.0) Gecko/20130801 Thunderbird/17.0.8 In-Reply-To: <5e23a0e9-2bd9-4f62-aa83-47bea8144eae@isocpp.org> X-Original-Sender: bengt.gustafsson@beamways.com X-Original-Authentication-Results: mx.google.com; spf=neutral (google.com: 213.180.89.90 is neither permitted nor denied by best guess record for domain of bengt.gustafsson@beamways.com) smtp.mail=bengt.gustafsson@beamways.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:5915 Archived-At: How about doing the change in the other end: Don't change anything in the class head, but allow an implicit=20 transformation: object.property =3D value; to object.property(value); IFF property is a function which has an overload that can be called with=20 a single parameter of value's type. As function pointers and functions are different I don't see that this=20 can interfer with an assignment that is allowed today. Also this is=20 consistent with what is already allowed at construction time! The getter case is a little harder to accept for me, but I think it=20 would be possible to allow: int value =3D object.property; IFF property is a method which has a 0-ary overload. I am not positive but at least I think that using the address of a=20 method without a leading & is not allowed when you really want to get at=20 the method pointer, so this should not be ambiguous. In contrast, it=20 would not be possible to omit the trailing () for a global function as=20 (due to feature inheritance from C) this means the address of the=20 function (correct me if I'm wrong on this). Personally I am so entrenched with C++ that I don't really understand=20 how property syntax would improve the world, but if it is to enter the=20 language it seems that it can be done without adding keywords or=20 additional messy declarations in the headers. I do think that my=20 suggested approach could have some inherent dangers that I don't see=20 right now, especially the getter part of it. Even if properties implemented like this could be parsed unambiguously=20 there is also the risk of too little redundancy: If every possible=20 combination of letters has a valid meaning there will be no error=20 messages to warn you when you are doing the wrong things with unexpected=20 results. --=20 Bengt Gustafsson CEO, Beamways AB Westmansgatan 37A 582 16 Link=F6ping, Sweden +46 13 465 10 85 www.beamways.com --=20 ---=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. Visit this group at http://groups.google.com/a/isocpp.org/group/std-proposa= ls/. .