220 37210 article Path: news.gmane.org!.POSTED!not-for-mail From: Larry Evans Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: General purpose utilities for template metaprogramming and type manipulation Date: Mon, 5 Mar 2018 02:16:57 -0600 Lines: 38 Approved: news@gmane.org Message-ID: References: Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8"; format=flowed X-Trace: blaine.gmane.org 1520237721 27130 195.159.176.226 (5 Mar 2018 08:15:21 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Mon, 5 Mar 2018 08:15:21 +0000 (UTC) User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBDAYTI72VMGRBAX26PKAKGQEGXA3Y6I@isocpp.org Mon Mar 05 09:15:17 2018 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-lf0-f72.google.com ([209.85.215.72]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1eslGu-0004Ut-Up for gclcip-std-proposals@m.gmane.org; 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Original-Received: from list by blaine.gmane.org with local (Exim 4.84_2) (envelope-from ) id 1eslGr-000414-Fx for std-proposals@isocpp.org; Mon, 05 Mar 2018 09:14:57 +0100 X-Injected-Via-Gmane: http://gmane.org/ Original-Lines: 31 Original-X-Complaints-To: usenet@blaine.gmane.org In-Reply-To: Content-Language: en-US X-Original-Sender: cppljevans@suddenlink.net X-Original-Authentication-Results: mx.google.com; spf=neutral (google.com: 195.159.176.226 is neither permitted nor denied by best guess record for domain of gclcip-std-proposals@m.gmane.org) smtp.mailfrom=gclcip-std-proposals@m.gmane.org 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:37210 Archived-At: On 03/04/2018 12:55 AM, Vincent Reverdy wrote: > Hey, > > I was starting to think about putting together a proposal to add minor > helper classes to either type_traits/utility/tuple to help with some of the > operations done again and again when doing template metaprogramming. > Here is a list of a few I can think of, but I would have liked to hear > other suggestions. Names are just indicative, and bikeshedding would happen > for all of these types. > > > - *std::blank*, defined as an empty struct > struct blank{}; or: using blank=std::tuple<>; another name is unit: https://en.wikipedia.org/wiki/Unit_type > - *std::pack*, to hold a parameter pack of type > template struct pack{}; > - *std::convertible*, a type convertible to anything > struct convertible{template constexpr operator T() const > noexcept;}; > - *std::copy_qualifiers*, a type traits copying ref and cv qualifiers > from one type to another > template struct copy_qualifiers {using type = /* > cv-ref qualfiers of From applied to To*/;}; > > Other suggestions? > https://github.com/cppljevans/variadic_templates/blob/master/boost/mpl/while.hpp https://github.com/cppljevans/variadic_templates/blob/master/boost/mpl/if_recur.hpp -- You received this message because you are subscribed to the Google Groups "ISO C++ Standard - Future Proposals" group. 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