220 29863 <296450916.pPnEejVmnO@tjmaciei-mobl1> article Path: news.gmane.org!.POSTED!not-for-mail From: Thiago Macieira Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Default constructor for lambdas Date: Fri, 16 Dec 2016 22:33:51 -0800 Lines: 31 Approved: news@gmane.org Message-ID: <296450916.pPnEejVmnO@tjmaciei-mobl1> References: <13497310-30de-4542-9ba4-fb1fbd730cb6@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-Trace: blaine.gmane.org 1481956439 31539 195.159.176.226 (17 Dec 2016 06:33:59 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Sat, 17 Dec 2016 06:33:59 +0000 (UTC) User-Agent: KMail/5.3.3 (Linux/4.8.13-1-default; KDE/5.28.0; x86_64; ; ) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBCB4TK757YBRBU5Y2PBAKGQE3FQBX4I@isocpp.org Sat Dec 17 07:33:55 2016 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-lf0-f71.google.com ([209.85.215.71]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1cI8Z6-0006w0-BN for gclcip-std-proposals@m.gmane.org; Sat, 17 Dec 2016 07:33:52 +0100 Original-Received: by mail-lf0-f71.google.com with SMTP id g12sf12726415lfe.5 for ; Fri, 16 Dec 2016 22:33:56 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=isocpp-org.20150623.gappssmtp.com; s=20150623; h=from:to:subject:date:message-id:user-agent:in-reply-to:references :mime-version: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=Mr6msET42WoNZx3SQuek0ivxmZtxVDyUTrf8FqYGK1A=; b=I4Pts6pk140i3c5a7laswkgiYKbDC+u39u76D10X+aYugncDGh0IGAOmAPrCvKemH7 fkHhjcrrAcJzwSvuMvi0wAICWDDqS6frFFZOHeSyeNKVQQqj4K/DZNCQa3V2Sf42qgc1 rs+dHBWOlxdK7YU4fox7Rw5yl5EYpo9+IuDEprtTvXjoqqoGjPUDt7mLCPAXS/v708V+ AQj1aNIGBqp2zEOQ92MBmFNOC1AKjRUpF5GcEaR1H3siheXtODmf6LCkSchnjxcvE7Ur 8nBOou8uDbRV48aNGOHzrgfFEtH240kLffRvDB8REmVC9qXZrCk1+AWS0l9rj7U9obiW Pstg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:subject:date:message-id:user-agent :in-reply-to:references:mime-version: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=Mr6msET42WoNZx3SQuek0ivxmZtxVDyUTrf8FqYGK1A=; b=Nwzl4LVKNwOo6CBurduc1lN3ENQ8nGycVmDdfo6wHzGv9n1t7kfu25kF9cQlaPCj7R UtxpZVUKDgttuVwznYKISGTrUPvbkm2+8PnnSKNXJwfL1N2cLvqyBpjhN9TLOb52DfEu lwcO2sc4JImciGxxqduAtwx9Jy1sNOYDEI7bhXI4C+Wt3k5xeJLk+11b7viQkeJxW2+0 +6MMVBIw697rUecqnrL9s3iOWEM69qguIYDZyFiqsfQzhZVyRInDIyKRl+FDOQpATojf ICTpqerTrQMYO+jSDpF3pWSkhBrx+WKhHjPzJPL7SQo8GOIXpD0D2r7KoItw4a++h7v7 0YAQ== X-Gm-Message-State: AIkVDXKqmCVVO8E0jcXt7DOZjU2lzcUcX7migFGynwD5tzpzIPoxh3mqVZMB2VXPIj4KqA== X-Received: by 10.46.5.209 with SMTP id 200mr637178ljf.11.1481956436485; Fri, 16 Dec 2016 22:33:56 -0800 (PST) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.28.148.208 with SMTP id w199ls573058wmd.2.canary-gmail; Fri, 16 Dec 2016 22:33:55 -0800 (PST) X-Received: by 10.28.226.7 with SMTP id z7mr5930414wmg.83.1481956434966; Fri, 16 Dec 2016 22:33:54 -0800 (PST) Original-Received: from gondolin.macieira.info (gondolin.macieira.info. [2a01:4f8:d13:f81:21c:14ff:fe01:12a3]) by mx.google.com with ESMTP id p194si7241232wme.0.2016.12.16.22.33.54 for ; Fri, 16 Dec 2016 22:33:54 -0800 (PST) Received-SPF: pass (google.com: domain of thiago@macieira.org designates 2a01:4f8:d13:f81:21c:14ff:fe01:12a3 as permitted sender) client-ip=2a01:4f8:d13:f81:21c:14ff:fe01:12a3; Original-Received: from tjmaciei-mobl1.localnet (unknown [IPv6:2601:1c0:4501:5f9f:c54a:9ee:a270:4023]) by gondolin.macieira.info (Postfix) with ESMTPSA id EDE9B11B3C3 for ; Fri, 16 Dec 2016 22:33:53 -0800 (PST) In-Reply-To: <13497310-30de-4542-9ba4-fb1fbd730cb6@isocpp.org> X-Original-Sender: thiago@macieira.org X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of thiago@macieira.org designates 2a01:4f8:d13:f81:21c:14ff:fe01:12a3 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:29863 Archived-At: On sexta-feira, 16 de dezembro de 2016 14:47:45 PST Vincent Reverdy wrote: > Hello. > > What is the reason why lambdas have no default constructor? Is there any > technical reason behind that, or is it a pure design decision? What would you initialise the captures-by-reference to? [i] { ++i; } has struct equivalent: struct Lambda { int &i; Lambda(int &i) : i(i) {} operator()() { ++i; } }; The above cannot have a default constructor. -- Thiago Macieira - thiago (AT) macieira.info - thiago (AT) kde.org Software Architect - Intel Open Source Technology Center -- 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. To view this discussion on the web visit https://groups.google.com/a/isocpp.org/d/msgid/std-proposals/296450916.pPnEejVmnO%40tjmaciei-mobl1. .