220 24005 <56A5B65C.7000504@gmail.com> article Path: news.gmane.org!not-for-mail From: Cleiton Santoia Silva Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Question about N4447 Date: Mon, 25 Jan 2016 03:45:00 -0200 Organization: VTT Lines: 59 Approved: news@gmane.org Message-ID: <56A5B65C.7000504@gmail.com> References: 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 1453700702 12336 80.91.229.3 (25 Jan 2016 05:45:02 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Mon, 25 Jan 2016 05:45:02 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBCBMVWMTUUNBBUPMS22QKGQE6A6XBPY@isocpp.org Mon Jan 25 06:44:55 2016 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-ig0-f200.google.com ([209.85.213.200]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1aNZxM-0004OB-AB for gclcip-std-proposals@m.gmane.org; Mon, 25 Jan 2016 06:44:52 +0100 Original-Received: by mail-ig0-f200.google.com with SMTP id rs1sf113094878igb.3 for ; Sun, 24 Jan 2016 21:44:51 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=isocpp-org.20150623.gappssmtp.com; s=20150623; h=subject:to:references:from:organization: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=8kusY3m+RdIMuRLZ1v8U0ZGyN8oTW6/1Izr/Wh5m+I0=; b=EK/DNR0US6WvxlA9yq0XEHraeHlh/i/8AwrhNSZHf7ltnr+sTabZjLFj+js/8ZErGp 5M5v2POsZT0pLGSEgDzXkx04v51VO6bdcFqhovurPLbnxQwUabaEm9dXiAAH/a1LJ9pP DfUgIEqmA+Ms5yJAZNp/m+rlLO+NmndubbwIiMm74xcnvKN9T+gJTJKt6KvwWdyAD7+o jLUEi/IMaT/o9Ww+FB3jQQkj5uzhrGz6/DXi9pxYyN4XHinMZXUgrZusX8F9I1F9CNAd YXOG0bRUy8cR8xTG4GDVf4XCPVJgXEmttsC/l6f0BY6cDjnncyeqFbSqLu+hYU8zu2NE 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:organization :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=8kusY3m+RdIMuRLZ1v8U0ZGyN8oTW6/1Izr/Wh5m+I0=; b=f/krXD+x0hRQ/7/Ayjl2V31cbVsLtsM2d9qekT9z9/jK1YC+1lNd6j2J/pzqPd3ft6 zmDVsts4szCN0zV1N/xuweVp2mtcIDotYtiVUYwBIp7EEVLAGriAxpzIDOLIAjMMcRKo /N9sxFRhv7RtTSZsKIcXxHvS/+2/OS04TVZxHPNxaKMmaIFj+EhXVHih6PBrMnc3VSpT yUnmMpU7btU2KiQk/tcTYBu3R7W3bmSzpL7Lo9yJ/WI2fmSnGtp4tuJb6Qzw5eV8+mLx v20pMDTmHt/Y61BXb1Xv9IjmuusONhsOKgLOxqi7VSCQbTud5M59SEJVR4JTq+Cl2Smu X-Gm-Message-State: AG10YOTg2zTWhLR1lP9jtw+lG07kDoxB6kbLqz4sB0Av+x379LAlFcs4uVaxvEQZann/OQ== X-Received: by 10.182.39.138 with SMTP id p10mr7910056obk.16.1453700691195; Sun, 24 Jan 2016 21:44:51 -0800 (PST) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.140.105.75 with SMTP id b69ls1682822qgf.53.gmail; Sun, 24 Jan 2016 21:44:49 -0800 (PST) X-Received: by 10.55.82.214 with SMTP id g205mr18707114qkb.72.1453700689580; Sun, 24 Jan 2016 21:44:49 -0800 (PST) Original-Received: from mail-qk0-x22d.google.com (mail-qk0-x22d.google.com. [2607:f8b0:400d:c09::22d]) by mx.google.com with ESMTPS id y200si22641844qhy.25.2016.01.24.21.44.49 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sun, 24 Jan 2016 21:44:49 -0800 (PST) Received-SPF: pass (google.com: domain of cleitonsantoia@gmail.com designates 2607:f8b0:400d:c09::22d as permitted sender) client-ip=2607:f8b0:400d:c09::22d; Original-Received: by mail-qk0-x22d.google.com with SMTP id o6so50786365qkc.2 for ; Sun, 24 Jan 2016 21:44:49 -0800 (PST) X-Received: by 10.55.77.216 with SMTP id a207mr18798577qkb.80.1453700689359; Sun, 24 Jan 2016 21:44:49 -0800 (PST) Original-Received: from [192.168.0.2] ([177.33.125.174]) by smtp.gmail.com with ESMTPSA id h64sm8155217qgh.39.2016.01.24.21.44.47 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sun, 24 Jan 2016 21:44:48 -0800 (PST) User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.5.1 In-Reply-To: X-Original-Sender: cleitonsantoia@gmail.com X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of cleitonsantoia@gmail.com designates 2607:f8b0:400d:c09::22d as permitted sender) smtp.mailfrom=cleitonsantoia@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:24005 Archived-At: That would be good, make the expansion in "lock". I gave some thoughts on this matter, however there is a problem with you syntax, what happens if you ask for typedef<> and typeid<> of different classes ? This problem can be solved in other way, you can ask for typeid< M > on each member of typedef, and make other class ( descendant of yours ) to encapsulate that : template struct Member_son : Member { constexpr Memeber(_Member m) : Member(m, typeid<_Member>...) {} }; vector members = { typedef... }; This should give what you want. Cleiton Em 22/01/2016 16:52, gufideg@gmail.com escreveu: > Hi. I've been thinking about N4447 lately. First, this proposal is wonderful. It's something I dreamt of a long time. Thanks everyone. > > I have a question about it: the syntax use the `...` To expand the result. Does this mean it follows all the same rules as the parameter pack expansion? Let me explain. > > Let's say we have this struct: > > template > struct Member { > constexpr Memeber(T Class::*aMember, const char* aName) : member{aMember}, name{aName} {} > > using Type = T; > > T Class::*member; > const char* name; > }; > > template > constexpr auto makeMember(T Class::*member, const char* name) { > return Member{member, name}; > } > > With the current proposal, is it possible to write something like this? > > constexpr auto members = std::make_tuple( makeMember(typedef, typeid)... ); > > Note that I used both `typedef<...>`and `typeid<...>` with the same expansion. > -- --- 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 https://groups.google.com/a/isocpp.org/group/std-proposals/. .