220 15275 article Path: news.gmane.org!not-for-mail From: Ville Voutilainen Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Re: Some constexpr changes. Date: Wed, 24 Dec 2014 11:22:34 +0200 Lines: 31 Approved: news@gmane.org Message-ID: References: <16df9eb7-5793-40b1-96c5-f98cd6ffcb7f@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 1419412963 25253 80.91.229.3 (24 Dec 2014 09:22:43 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Wed, 24 Dec 2014 09:22:43 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBC5JHI7A7ALRBWUL5KSAKGQEMLBKGYY@isocpp.org Wed Dec 24 10:22:37 2014 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-ie0-f198.google.com ([209.85.223.198]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1Y3i9M-00007S-N6 for gclcip-std-proposals@m.gmane.org; Wed, 24 Dec 2014 10:22:36 +0100 Original-Received: by mail-ie0-f198.google.com with SMTP id y20sf43209861ier.9 for ; Wed, 24 Dec 2014 01:22:35 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:in-reply-to:references:date :message-id:subject:from:to:content-type:x-original-sender :x-original-authentication-results:reply-to:precedence:mailing-list :list-id:list-post:list-help:list-archive:list-subscribe :list-unsubscribe; bh=Gx+CoFD88ETn0wcbdSmNKxaQDcRm7IJrDPg9wEVNBDo=; b=EwRUCTXIrGXjWeFYz+VaXnNZQ+eoTx56TlHWadzmkVGdtNa8xsbNOEVqJcnGwhZTXU Ish2ng8XZb8uHsxUfzUPaYtEt6QK9HNKvH0KMC7YZnaUYFRTZN4kuv0zBHo2pZ6QQAh9 W3r2XtIcn25tupRtBA4gS5wgh2QnC1fk/DmhU8Ildc/XoBSyhVqNVqlL/5dJxYNuR1ow NayXHxmHiKofoqhAoGaSnl4EuPvMrSMAmpB8IGs+Ba62gkg9x+fLOZI8WMAaBhQheUcU RufX36HYX3g64bP2ijy8t7Px++ogxQO16CJqIrdrlOoOjjpUOt5nmowjd+iKUqy5wn5H Ia3Q== X-Gm-Message-State: ALoCoQk7MOj6uKYn4Z7gBv2RWs3c3sIplNdVMAYpEwu98hRtYVUQL5OCpE7AV8x/qeUwEWeZTKc3 X-Received: by 10.182.110.196 with SMTP id ic4mr24778722obb.41.1419412955312; Wed, 24 Dec 2014 01:22:35 -0800 (PST) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.182.116.162 with SMTP id jx2ls2473872obb.83.gmail; Wed, 24 Dec 2014 01:22:34 -0800 (PST) X-Received: by 10.60.84.196 with SMTP id b4mr19201347oez.49.1419412954753; Wed, 24 Dec 2014 01:22:34 -0800 (PST) Original-Received: from mail-ob0-x236.google.com (mail-ob0-x236.google.com. [2607:f8b0:4003:c01::236]) by mx.google.com with ESMTPS id e9si14033629obr.50.2014.12.24.01.22.34 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Wed, 24 Dec 2014 01:22:34 -0800 (PST) Received-SPF: pass (google.com: domain of ville.voutilainen@gmail.com designates 2607:f8b0:4003:c01::236 as permitted sender) client-ip=2607:f8b0:4003:c01::236; Original-Received: by mail-ob0-f182.google.com with SMTP id wo20so28692310obc.13 for ; Wed, 24 Dec 2014 01:22:34 -0800 (PST) X-Received: by 10.182.50.225 with SMTP id f1mr19031533obo.45.1419412954626; Wed, 24 Dec 2014 01:22:34 -0800 (PST) Original-Received: by 10.76.154.2 with HTTP; Wed, 24 Dec 2014 01:22:34 -0800 (PST) In-Reply-To: <16df9eb7-5793-40b1-96c5-f98cd6ffcb7f@isocpp.org> X-Original-Sender: ville.voutilainen@gmail.com X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of ville.voutilainen@gmail.com designates 2607:f8b0:4003:c01::236 as permitted sender) smtp.mail=ville.voutilainen@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-Google-Group-Id: 399137483710 List-Post: , List-Help: , List-Archive: List-Subscribe: , List-Unsubscribe: , Xref: news.gmane.org gmane.comp.lang.c++.isocpp.proposals:15275 Archived-At: On 23 December 2014 at 20:01, sasho648 wrote: >> How does this part change anything from the status quo? > It's different in that evaluating the function at compile-time wouldn't > produce any run-time code. Neither does the existing evaluation of a constant expression, if the target context of that expression is a constexpr variable. I guess you want to be able to guarantee that target contexts that can be either constant expression or runtime values, like indexing operator arguments would benefit from being required to be constant expressions. There are indirect ways to do that; instead of writing myArray[getSomeValue()]; one would need constexpr int foo = getSomeValue(); myArray[foo]; There are, naturally, situations where that is infeasible. For such situations, perhaps we'd need to allow constexpr lambdas instead of making changes or additions to constexpr functions? -- --- 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. 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