220 19931 <55D4CD4A.8070803@gmail.com> article Path: news.gmane.org!not-for-mail From: Andrey Semashev Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: default arguments Date: Wed, 19 Aug 2015 21:39:06 +0300 Lines: 42 Approved: news@gmane.org Message-ID: <55D4CD4A.8070803@gmail.com> References: <89bf9d09-00ed-45db-bf88-39c844707bd1@isocpp.org> <87b15f40-b36a-47bd-b822-8df53dd72287@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed X-Trace: ger.gmane.org 1440009570 6946 80.91.229.3 (19 Aug 2015 18:39:30 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Wed, 19 Aug 2015 18:39:30 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBCXY5TXHWYJRBTM22OXAKGQEFYAX6EI@isocpp.org Wed Aug 19 20:39:25 2015 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-wi0-f199.google.com ([209.85.212.199]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1ZS8GU-0005UI-9n for gclcip-std-proposals@m.gmane.org; Wed, 19 Aug 2015 20:39:10 +0200 Original-Received: by wilj18 with SMTP id j18sf5129486wil.0 for ; Wed, 19 Aug 2015 11:39:09 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:subject:to:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-type:x-original-sender :x-original-authentication-results:reply-to:precedence:mailing-list :list-id:x-spam-checked-in-group:list-post:list-help:list-archive :list-subscribe:list-unsubscribe; bh=SgJOowQ0iNPLzbv58xV23T+bMKIZLNDpxY8ZNAqsYaY=; b=iFr4tACIAxX1oUbVxEyOBHfwpi3n6gJF57kHJvPYbBgaIZJoXexB6fM6CdV3KopaHv bheMJ+m4/drR07sgYs2H8Zhpyv48nwwVv5HIZ0QAYZM5h3I3cKeQnn4OSiezxtj1HyIV jRRQR5PMEF/TfFdFAo3aAPLFNpkNWApeB4HpkJZ8RIyJF1wMM3kjp2DP5hIk2pEOR7mD dsucHb333uOh0aZb+gezKcK6d4xz1iD6MQxDi3op3a3emKdQ3oiKS460LHyghLjQPmur bWQnfkznZAzV6J90PDhrPHdKffAAxsXejYZQbwIjUzpqrIeVAqt5kN0pnPC5v2HdONYA Gqew= X-Gm-Message-State: ALoCoQlfUldP6MQEMYSWekJdVEx1ktArHWm6sxmmTuDkgnABPfRnLTfGuXkYE0bRW8IpSHmkx7c5 X-Received: by 10.112.17.106 with SMTP id n10mr2339690lbd.18.1440009549756; Wed, 19 Aug 2015 11:39:09 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.152.121.38 with SMTP id lh6ls52240lab.47.gmail; Wed, 19 Aug 2015 11:39:08 -0700 (PDT) X-Received: by 10.152.206.73 with SMTP id lm9mr1542294lac.0.1440009548505; Wed, 19 Aug 2015 11:39:08 -0700 (PDT) Original-Received: from mail-la0-x235.google.com (mail-la0-x235.google.com. 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[178.140.129.233]) by smtp.googlemail.com with ESMTPSA id tj8sm443756lbb.22.2015.08.19.11.39.06 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 19 Aug 2015 11:39:06 -0700 (PDT) User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.2.0 In-Reply-To: <87b15f40-b36a-47bd-b822-8df53dd72287@isocpp.org> X-Original-Sender: andrey.semashev@gmail.com X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of andrey.semashev@gmail.com designates 2a00:1450:4010:c03::235 as permitted sender) smtp.mailfrom=andrey.semashev@gmail.com; dkim=pass header.i=@gmail.com; dmarc=pass (p=NONE dis=NONE) header.from=gmail.com Precedence: list Mailing-list: list std-proposals@isocpp.org; contact std-proposals+owners@isocpp.org List-ID: X-Spam-Checked-In-Group: std-proposals@isocpp.org 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:19931 Archived-At: On 19.08.2015 21:07, Arthur Tchaikovsky wrote: > Not all members in struct are public. From elementary school, everyone > knows that struct differs from class that *by default* members are > public in struct and private in class. ;) > That's why I see it as a violation of encapsulation. I don't see the connection between the default access mode and encapsulation. Encapsulation is implementation hiding. It can be achieved by different means, including but not limited to member access management. Classes are no different from structs except for the default access mode - both can be used to achieve the same level of encapsulation. And no, all-public structs do not violate encapsulation in general. For instance, std::pair - a struct with public data, does not break encapsulation of std::(unordered_)map. > Secondly, not only > structs should be concerned, but classes too. And not only > initialization should be a concern here but also setting value *after* > the object had been initialized. Taken all this above, I say that > accessing members of a class/struct by names, be it during > initialization or after that fact is violation of encapsulation and it > should be discouraged in modern C++. This kind of code may very well be > OK for C but C++ is not C. I don't mean to sound harsh, but that's narrow minded thinking. The 'OOP everywhere' era has passed as people realized that it is not efficient in all scenarios. C-style structs are useful in some contexts and named member initialization is useful as well. See ffmpeg code for instance, the way codecs and formats are described. That's C, naturally, but imagine how much more code that would require in today's C++ with private members, constructors and default arguments. And then imagine how difficult it would be to modify the struct used as the descriptor. -- --- You received this message because you are subscribed to the Google Groups "ISO C++ Standard - Future Proposals" group. 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