220 12897 article Path: news.gmane.org!not-for-mail From: Sean Middleditch Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Re: unevaluated this Date: Mon, 15 Sep 2014 14:10:30 -0700 Lines: 115 Approved: news@gmane.org Message-ID: References: <009e6218-1e2b-402d-ab1a-e8ebf29f8f77@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-Trace: ger.gmane.org 1410815441 10517 80.91.229.3 (15 Sep 2014 21:10:41 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Mon, 15 Sep 2014 21:10:41 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBCDODCNR2QPRBR5L3WQAKGQEEVREXOI@isocpp.org Mon Sep 15 23:10:34 2014 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-we0-f200.google.com ([74.125.82.200]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1XTdXd-0002do-5p for gclcip-std-proposals@m.gmane.org; Mon, 15 Sep 2014 23:10:33 +0200 Original-Received: by mail-we0-f200.google.com with SMTP id u57sf2609584wes.11 for ; Mon, 15 Sep 2014 14:10:32 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:sender:in-reply-to:references:date :message-id:subject:from: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=Cpg+KSdvDQD+CeHC5REyHv/vAlWEeTfZP6Oe4X4Flw4=; b=mgBpZfWrZYsSwAY4APKYn7t00FA3XHOc9mAfPY1jFl6qoDZuN0xKSFbCoUjW+Whlvw EOfMo8Yr6Wk07tEGDXKhVKnP989ffWsw+fIFvx29lwpX4SohQyryXteUsi5xcFS9zhQV TICI/UBLd+hEZCIA5ODmvvrhq8ZPc7t9PeYej+KtysAAJUTq2WjFY7HprN2QaP8JbcQd raDjmcu0LyHrzqEgP+5ipXJ2hmOEyZZdeJ1w2cjMuQsoRckwKbZhYXWzew+/f6RLL/HF YptoBC1ZdWZ29Gh2qqt7Fj/kwKAH67Dr8NlT9YEIUaRi2E1P/wsOVk10woy2fP+hc3nG mNNw== X-Gm-Message-State: ALoCoQn/2+9GTqbl8jSyRIPEbPjlOJdUX9brS4Tm9kDwtevNvrF0qzeeZjgtJkVqCT9qf/Pw8sjX X-Received: by 10.180.81.226 with SMTP id d2mr5859490wiy.5.1410815432843; Mon, 15 Sep 2014 14:10:32 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.180.105.100 with SMTP id gl4ls507096wib.9.canary; Mon, 15 Sep 2014 14:10:31 -0700 (PDT) X-Received: by 10.194.95.66 with SMTP id di2mr35872023wjb.47.1410815431062; Mon, 15 Sep 2014 14:10:31 -0700 (PDT) Original-Received: from mail-wi0-x234.google.com (mail-wi0-x234.google.com [2a00:1450:400c:c05::234]) by mx.google.com with ESMTPS id uy10si20836332wjc.178.2014.09.15.14.10.30 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Mon, 15 Sep 2014 14:10:30 -0700 (PDT) Received-SPF: pass (google.com: domain of sean.middleditch@gmail.com designates 2a00:1450:400c:c05::234 as permitted sender) client-ip=2a00:1450:400c:c05::234; Original-Received: by mail-wi0-f180.google.com with SMTP id ex7so4988332wid.7 for ; Mon, 15 Sep 2014 14:10:30 -0700 (PDT) X-Received: by 10.180.9.73 with SMTP id x9mr12836667wia.20.1410815430654; Mon, 15 Sep 2014 14:10:30 -0700 (PDT) Original-Sender: sean.middleditch@gmail.com Original-Received: by 10.194.77.131 with HTTP; Mon, 15 Sep 2014 14:10:30 -0700 (PDT) In-Reply-To: X-Original-Sender: sean@middleditch.us X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of sean.middleditch@gmail.com designates 2a00:1450:400c:c05::234 as permitted sender) smtp.mail=sean.middleditch@gmail.com; dkim=pass header.i=@gmail.com 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:12897 Archived-At: That makes a lot of sense. I'll remove it and just focus on the unevaluated this part. Thanks! On Mon, Sep 15, 2014 at 2:00 PM, Richard Smith wrote: > On Mon, Sep 15, 2014 at 12:39 PM, Sean Middleditch > wrote: >> >> Yeah, that was one of the open questions. Would using the this_t<> >> alternative (delaying the instantiation until the appropriate context) >> work? >> >> The this_t idea is just to offer a convenience shorthand. I don't >> think it's necessary, and the my_type you present is certainly >> acceptable; this isn't something users are expected to use directly >> too often. > > > The this_t thing doesn't work: 'this' will be interpreted in the context in > which it appears, and in the definition of 'this_t' it appears outside a > class, so is ill-formed. > >> >> Thanks! >> >> On Mon, Sep 15, 2014 at 11:32 AM, Myriachan wrote: >> > On Monday, September 15, 2014 9:17:17 AM UTC-7, Sean Middleditch wrote: >> >> >> >> Another proposal carrying on from work I did earlier. This is a >> >> continuation of the decltype(class) feature I suggested some time back >> >> but >> >> with Ville's suggestion taken to heart. It's now a proposal for >> >> allowing >> >> `this` in unevaluated contexts (decltype, sizeof, etc.) anywhere in a >> >> class >> >> definition body or base specifier list as well as a convenient helper >> >> `std::this_t`. >> >> >> >> >> >> >> >> http://htmlpreview.github.io/?https://github.com/seanmiddleditch/CPlusPlus/blob/master/unevaluated-this.html >> >> >> >> Thoughts/comments/critiques would be appreciated. Thanks! >> > >> > >> > I don't see how std::this_t could be implemented, because there's no way >> > it >> > could know in which context it's being used. Other than the amount of >> > typing, this would work fine if this is allowed throughout class scope >> > in >> > all unevaluated contexts: >> > >> > using my_type = >> > std::remove_cv_t>; >> > >> > Melissa >> > >> > -- >> > >> > --- >> > You received this message because you are subscribed to a topic in the >> > Google Groups "ISO C++ Standard - Future Proposals" group. >> > To unsubscribe from this topic, visit >> > >> > https://groups.google.com/a/isocpp.org/d/topic/std-proposals/pienLjyOVJk/unsubscribe. >> > To unsubscribe from this group and all its topics, 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 >> > http://groups.google.com/a/isocpp.org/group/std-proposals/. >> >> >> >> -- >> Sean Middleditch >> http://seanmiddleditch.com >> >> -- >> >> --- >> 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 >> http://groups.google.com/a/isocpp.org/group/std-proposals/. > > > -- > > --- > You received this message because you are subscribed to a topic in the > Google Groups "ISO C++ Standard - Future Proposals" group. > To unsubscribe from this topic, visit > https://groups.google.com/a/isocpp.org/d/topic/std-proposals/pienLjyOVJk/unsubscribe. > To unsubscribe from this group and all its topics, 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 > http://groups.google.com/a/isocpp.org/group/std-proposals/. -- Sean Middleditch http://seanmiddleditch.com -- --- 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 http://groups.google.com/a/isocpp.org/group/std-proposals/. .