220 19896 article Path: news.gmane.org!not-for-mail From: Andrey Semashev Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Re: default arguments Date: Tue, 18 Aug 2015 19:49:06 +0300 Lines: 38 Approved: news@gmane.org Message-ID: References: <7066b166-9472-4ad6-ac3c-2db527ed7818@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 X-Trace: ger.gmane.org 1439916554 14280 80.91.229.3 (18 Aug 2015 16:49:14 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Tue, 18 Aug 2015 16:49:14 +0000 (UTC) Cc: mwoehlke.floss@gmail.com To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBCXY5TXHWYJRBA6EZWXAKGQEYJFNYKY@isocpp.org Tue Aug 18 18:49:13 2015 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-yk0-f198.google.com ([209.85.160.198]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1ZRk4S-0001ON-LL for gclcip-std-proposals@m.gmane.org; Tue, 18 Aug 2015 18:49:08 +0200 Original-Received: by ykll84 with SMTP id l84sf135690349ykl.0 for ; Tue, 18 Aug 2015 09:49:07 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:in-reply-to:references:date :message-id:subject:from:to:cc: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=USwOADMDrfO8++3OF5F7Z5qx30vgIX0v9TjIcs1UVuk=; b=cITHEBgm2vpUgPiuFfEFa5pB8p5juuNPraSAc5GZV3+3wxbNxWfBZrLfmXjvWKbePe 4zXYdgISkqSS4YB5GYSQPnXg3jt4e//wD1tz5jHFInH/7lbifMDlGlWuHzeBLCS140mg jxloiSH72ifM7FIx33A5kO9kW0Sdjb1R2jBhOkEznPzhzLIBJ/i5ginTa4ArazPFkTCi gmAaUrzJtyA3s4IG2hK3aYQuVQP0G4ShMwnhpIRErUPcYcKeg8jyXTLyHyF/bIw3FW7w Ac5CG82FKH4w3PQldrxXf5Y8SxHVrDrgnnfXpyzzqHPCs/wFExfYznL3Bl0+68CLUL6k utgw== X-Gm-Message-State: ALoCoQn5LhrVQNAgQrINsy6lhyiOvUT4fKb0F0XtuWkTKidIGw69YPdobOd2vte8hFoaBMrSSTX9 X-Received: by 10.129.51.6 with SMTP id z6mr6868055ywz.48.1439916547634; Tue, 18 Aug 2015 09:49:07 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.50.66.229 with SMTP id i5ls1311042igt.8.gmail; Tue, 18 Aug 2015 09:49:06 -0700 (PDT) X-Received: by 10.107.162.9 with SMTP id l9mr7826577ioe.76.1439916546894; Tue, 18 Aug 2015 09:49:06 -0700 (PDT) Original-Received: from mail-io0-x229.google.com (mail-io0-x229.google.com. [2607:f8b0:4001:c06::229]) by mx.google.com with ESMTPS id t5si10093888igd.26.2015.08.18.09.49.06 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 18 Aug 2015 09:49:06 -0700 (PDT) Received-SPF: pass (google.com: domain of andrey.semashev@gmail.com designates 2607:f8b0:4001:c06::229 as permitted sender) client-ip=2607:f8b0:4001:c06::229; Original-Received: by iodb91 with SMTP id b91so195624228iod.1 for ; Tue, 18 Aug 2015 09:49:06 -0700 (PDT) X-Received: by 10.107.3.149 with SMTP id e21mr7364081ioi.19.1439916546660; Tue, 18 Aug 2015 09:49:06 -0700 (PDT) Original-Received: by 10.79.98.1 with HTTP; Tue, 18 Aug 2015 09:49:06 -0700 (PDT) In-Reply-To: <7066b166-9472-4ad6-ac3c-2db527ed7818@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 2607:f8b0:4001:c06::229 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:19896 Archived-At: On Tue, Aug 18, 2015 at 7:37 PM, Arthur Tchaikovsky wrote: > I dear to disagree with the statement that the following example is self > documenting and easier to read: > auto c3ptr = new C{.timeout = 1}; > How is this^^^ easier to read? And how is this self documenting? Only on > surface it seems that it is, both, but when you really think about it it is > neither self documenting nor easy to read. Why? Because having only one > argument initialized in {}, that is .timeout, leaves us with question, is > that the only argument to that class, or are there any other? If so, are > those arguments inited by default? If so, how many? Etc. > Compared to this: > auto c3ptr = new C(default, 1); // use a shorter timeout > It is immediately obvious how many arguments there are and which one of them > are default. Your argument works both ways - I cannot tell what other members C has and how they are initialized by this constructor. In addition I don't see what the constructor arguments are without looking at the interface or docs. > And as for self documentation? > auto c3ptr = new C(default, /*timeout*/1); // use a shorter timeout Multi-line comments are evil - they cause problems when you want to comment a block of code. Besides interface documentation I try to avoid them as much as possible. IMHO, the true named member initialization is much more self-explanatory and less error prone. -- --- 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/. .