220 12480 article Path: news.gmane.org!not-for-mail From: Jim Porter Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Placeholder literals Date: Mon, 25 Aug 2014 00:57:27 -0500 Lines: 42 Approved: news@gmane.org Message-ID: References: <570663A9-F617-442F-9B48-5B6E7311AE72@gmail.com> 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 1408946279 28192 80.91.229.3 (25 Aug 2014 05:57:59 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Mon, 25 Aug 2014 05:57:59 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBDYZZG6PQYFRBXNA5OPQKGQE64OA5WY@isocpp.org Mon Aug 25 07:57:51 2014 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-we0-f199.google.com ([74.125.82.199]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1XLnHr-0002wR-7f for gclcip-std-proposals@m.gmane.org; Mon, 25 Aug 2014 07:57:51 +0200 Original-Received: by mail-we0-f199.google.com with SMTP id p10sf7751212wes.6 for ; Sun, 24 Aug 2014 22:57:50 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:to:from:subject:date:lines:message-id:references :mime-version:user-agent:in-reply-to:x-original-sender :x-original-authentication-results:reply-to:precedence:mailing-list :list-id:list-post:list-help:list-archive:list-subscribe :list-unsubscribe:content-type; bh=w0vnkq4A3/Zdvun2ecjPnN7fCu9LfCSguLYaiAivGL8=; b=NGqCDwjUh0uRr2L/fRLGbRHEBmo3xtqaqQ4aI8EXLUkH66T0Gr9Ii1xKAivwRU1ve2 krrb+bPpeV2OfJoh4Ed+N1RdOzSUt7vOEbhlTdz64ly3xV1vgxkeMfR+Ar4Kr3c8MO+x aXryBsmAQq3VZu4nvirIEPaSLOgS1wXh8HuNuoOruraeZ6OqEM9s0X8rPhnK3EuSdcQ7 h08UGr0Qcx9BIw/FZI0SUWKU1lv4nj1aex8H4xHnyqCUR31zjCUu3tMOzJ9NfeKOd1KW GAsC5DsdzuBnR35R9zfZhdSNCephgQ4WUTkND3qXxPAGDl/1gKgljHomTwpp87ZsxFQd ptAw== X-Gm-Message-State: ALoCoQmN4Eruw0sWAjtKiQmizw9jyks/xYZD6octRYRlUJiU9dQbfaOk6KOLErqqWS5e1Vg+nKsu X-Received: by 10.180.189.69 with SMTP id gg5mr1048574wic.4.1408946270859; Sun, 24 Aug 2014 22:57:50 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.152.10.234 with SMTP id l10ls328095lab.88.gmail; Sun, 24 Aug 2014 22:57:48 -0700 (PDT) X-Received: by 10.153.6.39 with SMTP id cr7mr6749339lad.66.1408946268567; Sun, 24 Aug 2014 22:57:48 -0700 (PDT) Original-Received: from plane.gmane.org (plane.gmane.org. [80.91.229.3]) by mx.google.com with ESMTPS id ba4si51085349lbc.135.2014.08.24.22.57.48 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Sun, 24 Aug 2014 22:57:48 -0700 (PDT) Received-SPF: pass (google.com: domain of gclcip-std-proposals@m.gmane.org designates 80.91.229.3 as permitted sender) client-ip=80.91.229.3; Original-Received: from list by plane.gmane.org with local (Exim 4.69) (envelope-from ) id 1XLnHl-0002tP-EM for std-proposals@isocpp.org; Mon, 25 Aug 2014 07:57:45 +0200 Original-Received: from 71-87-112-150.dhcp.mdsn.wi.charter.com ([71.87.112.150]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Mon, 25 Aug 2014 07:57:45 +0200 Original-Received: from jvp4846 by 71-87-112-150.dhcp.mdsn.wi.charter.com with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Mon, 25 Aug 2014 07:57:45 +0200 X-Injected-Via-Gmane: http://gmane.org/ Original-Lines: 33 Original-X-Complaints-To: usenet@ger.gmane.org X-Gmane-NNTP-Posting-Host: 71-87-112-150.dhcp.mdsn.wi.charter.com User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:31.0) Gecko/20100101 Thunderbird/31.0 In-Reply-To: X-Original-Sender: jvp4846@g.rit.edu X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of gclcip-std-proposals@m.gmane.org designates 80.91.229.3 as permitted sender) smtp.mail=gclcip-std-proposals@m.gmane.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:12480 Archived-At: On 8/24/2014 11:45 PM, Richard Smith wrote: > On Sat, Aug 23, 2014 at 6:21 PM, David Krauss > wrote: > > Why not add literal operator templates returning placeholders? > > > Why not deprecate std::bind? Generic lambdas provide a better solution, > and we don't benefit from having two ways to do the same thing. For cases where you're not using placeholders, I sometimes find std::bind to be easier to read, e.g. when binding a random number engine and a distribution to make a nullary function object. I'd probably use std::bind (or something like it) a lot more if I could just partially-apply the first N arguments and not have to deal with placeholders at all, e.g.: int sum(int a, int b, int c) { return a + b + c; } auto x = std::partial_apply(sum, 1, 2); x(3); // returns 6 Relatedly, it'd be nice if std::mem_fn supported something similar where you could bind `this` to it, and get back an N-ary function: int MyClass::func(int, int); auto x = std::mem_fn(&MyClass::func, this); x(1, 2); In general, I agree that most times you're using placeholders for std::bind, a generic lambda would be better, but there might be room for some "simple" binding metafunctions to handle the common cases. - Jim -- --- 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. 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