220 28993 article Path: news.gmane.org!.POSTED!not-for-mail From: Zhihao Yuan Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Suggesting a syntax for wraping overload set Date: Wed, 19 Oct 2016 17:00:58 -0500 Lines: 59 Approved: news@gmane.org Message-ID: Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Trace: blaine.gmane.org 1476914493 26836 195.159.176.226 (19 Oct 2016 22:01:33 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Wed, 19 Oct 2016 22:01:33 +0000 (UTC) To: "std-proposals@isocpp.org" Original-X-From: std-proposals+bncBCSKRWMD4EHBBJW2T7AAKGQEB3A34QQ@isocpp.org Thu Oct 20 00:01:29 2016 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-vk0-f72.google.com ([209.85.213.72]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1bwyv7-0003rE-US for gclcip-std-proposals@m.gmane.org; Thu, 20 Oct 2016 00:01:10 +0200 Original-Received: by mail-vk0-f72.google.com with SMTP id q126sf31258734vkd.4 for ; Wed, 19 Oct 2016 15:01:12 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:sender:mime-version:from:date:message-id:subject :to:content-transfer-encoding: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=HZ91LI60h3ZEyKqF+TQ+M8QqhMWGK28CceeWajRtufE=; b=LrS2UbmzwjSW1FO0ccbOr6TRzOZ4tbyOcU64OgASxq5jas1fFibtmuNXmXXGNyVMgq SmNUihKbkexUGW4o7kJ3Q+f3U6cWlT3qIIM5G8TMl8b/sP19r6KtgKCiaZZLo+KJoaPq LcTxiTVSejM0JiL/1G6LOqEK0z6c70QT7nd4mCk3uwibVl6cnWPC5+Z4r5iQs7rTiinZ pviycPnF5sTwJCauI47xJxrizV9HhHBAVotrMIy8c4TY4lO8GidasrgjQYUQtCPhA6vs I8iE7FjbovBhHju91Lc/hamD9f916yQzoifNPNThnoTSUAtwd/C3hYhj9bYybP3lVv0b S8rg== X-Gm-Message-State: AA6/9RnLvbAjPzEM/RJnGG3wLbp9KT5oBqINxJ2SCW1ZwCYtIGnzV+sEyaQq9j/XVk/DCQ== X-Received: by 10.31.151.199 with SMTP id z190mr2587544vkd.14.1476914471801; Wed, 19 Oct 2016 15:01:11 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.107.20.72 with SMTP id 69ls1162253iou.32.gmail; Wed, 19 Oct 2016 15:01:10 -0700 (PDT) X-Received: by 10.99.49.133 with SMTP id x127mr4592916pgx.68.1476914470689; Wed, 19 Oct 2016 15:01:10 -0700 (PDT) Original-Received: from mail-s68.mailgun.info (mail-s68.mailgun.info. [184.173.153.196]) by mx.google.com with ESMTPS id b3si35292839pav.115.2016.10.19.15.01.10 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 19 Oct 2016 15:01:10 -0700 (PDT) Received-SPF: pass (google.com: domain of bounce+3f9131.69110-std-proposals=isocpp.org@miator.net designates 184.173.153.196 as permitted sender) client-ip=184.173.153.196; Original-Sender: zy@miator.net X-Mailgun-Sending-Ip: 184.173.153.196 X-Mailgun-Sid: WyI3MTBkYiIsICJzdGQtcHJvcG9zYWxzQGlzb2NwcC5vcmciLCAiNjkxMTAiXQ== Original-Received: from mail-vk0-f43.google.com (mail-vk0-f43.google.com [209.85.213.43]) by mxa.mailgun.org with ESMTP id 5807ed1b.7f64540a0fb0-in01; Wed, 19 Oct 2016 22:00:59 -0000 (UTC) Original-Received: by mail-vk0-f43.google.com with SMTP id q126so46447000vkd.2 for ; Wed, 19 Oct 2016 15:00:59 -0700 (PDT) X-Received: by 10.31.114.71 with SMTP id n68mr7638512vkc.129.1476914458854; Wed, 19 Oct 2016 15:00:58 -0700 (PDT) Original-Received: by 10.176.68.33 with HTTP; Wed, 19 Oct 2016 15:00:58 -0700 (PDT) X-Gmail-Original-Message-ID: X-Original-Sender: zy@miator.net X-Original-Authentication-Results: mx.google.com; dkim=pass header.i=@miator.net; spf=pass (google.com: domain of bounce+3f9131.69110-std-proposals=isocpp.org@miator.net designates 184.173.153.196 as permitted sender) smtp.mailfrom=bounce+3f9131.69110-std-proposals=isocpp.org@miator.net 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:28993 Archived-At: I gave the reason why I against using the following syntax [] funcname to lift an overload set / operators into a lambda expression: the captures are never used. Moreover, they may end up being misleading. Consider the member access support in p01192r2 prefixed with []: [] obj.data So this lambda captures obj or not? So I try to go back to the origin of the problem we are solving: we have various kinds of things which are close to callable, just not first-class. And the transformation we are doing are merely from f to \x -> f(x) In lambda calculus, we call this transformation Eta-expansion (=CE=B7-reduction for the reserve process, and =CE=B7-conversion for either -- adding or dropping an abstraction). Scala is a language that I know for using the term Eta-expansion in its language spec, because they face a similar problem -- methods are not functions. And my suggestion for C++ is very simple: etaexpr(funcname) etaexpr(std::iota) etaexpr(<) etc. A new keyword, etaexpr, seems never seen according to google and github, reads "Eta (wrapped/expanded) expression", and means "to wrap a lexical lookup / operator / member access into a lambda". --=20 Zhihao Yuan, ID lichray The best way to predict the future is to invent it. ___________________________________________________ 4BSD -- http://blog.miator.net/ --=20 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 e= mail 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/CAGsORuB4zNMAs7BCZnyqpZynYD1ERCrCYKK8eaQKybyEM9w= wog%40mail.gmail.com. .