220 30191 <42463446.MPeEFdAbRV@tjmaciei-mobl1> article Path: news.gmane.org!.POSTED!not-for-mail From: Thiago Macieira Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: enum_cast proposal Date: Tue, 03 Jan 2017 17:12:34 -0200 Lines: 38 Approved: news@gmane.org Message-ID: <42463446.MPeEFdAbRV@tjmaciei-mobl1> References: <2998762.etaySSRi7N@tjmaciei-mobl1> 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 1483470759 26430 195.159.176.226 (3 Jan 2017 19:12:39 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Tue, 3 Jan 2017 19:12:39 +0000 (UTC) User-Agent: KMail/5.3.3 (Linux/4.8.13-1-default; KDE/5.28.0; x86_64; ; ) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBCB4TK757YBRBJPPV7BQKGQE7GAZ74Q@isocpp.org Tue Jan 03 20:12:34 2017 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-qk0-f199.google.com ([209.85.220.199]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1cOUVe-0006Ds-Eu for gclcip-std-proposals@m.gmane.org; Tue, 03 Jan 2017 20:12:34 +0100 Original-Received: by mail-qk0-f199.google.com with SMTP id c69sf1879187qkg.1 for ; Tue, 03 Jan 2017 11:12:39 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=isocpp-org.20150623.gappssmtp.com; s=20150623; h=from:to:subject:date:message-id:user-agent:in-reply-to:references :mime-version: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=YYd83IepypTema5P95VKiegzRbyS11rC95NMrCFvqfo=; b=q4zqjt7t7kiNJ80uIylxM/bmw9MAoGlsCXFoWnO/Ylw7ZNu1jPb8lDR3xqkKhTR8VJ MH1spTiZQqIeFSXizwM/WSDGgQyVWh9JFScLci0goskRaWQG+nGab9V27dpGH3zD1qxb R5AKyN6ffXBHkdueVxnuF7S0Ux+ej3IMvg6VqAPrMewJ/yEe/AWeDQTigXaFv8dRK9cK zbUe37RD7DZTINO5gKeJrBYX/eSMdXYkWLDrwjRro2XokOR1NwgUlAEsYqOmt/5C2Llk lYnqm+hmqyltE1UTi0Jv3+qi+VHBSAKAZYpgnTxo+4XCW5PHZI/+sprZHlRdgE5jbXea X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:subject:date:message-id:user-agent :in-reply-to:references:mime-version: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=YYd83IepypTema5P95VKiegzRbyS11rC95NMrCFvqfo=; b=ShMoWUZvmcqIh9puskEuOwVZ9L1nF7tgP4+dqrj4DSOao8BxhNdmGMiHvTAgYZDoR2 q5BPYR2kAjXAhlTA5RWWCAbx6G0zUlH6hHXNaKGTParBGvsIzBmdTe/nVhsPY6Ky8CW6 pWcPgjsRua3xfvK3z08+WT5jecNBosNlihx9W49GTHA6UUNFeETywy82tXV7RLDGpRuS zDtCfpF/0BM+rMWlrPXFz/vxMH8j8Y3zrxRBymnZ+pAhwT/KcnRq72dccGgj2jw3XIA2 tYGeZz6RN0sdkoex+Jo5KzVzu/ZJmDXKF6BuADRtTpS2mQgAVGypMTq6e6XtLWtZf/Cm X-Gm-Message-State: AIkVDXIerC24ALtNesDu9+M7qS632O+mJaVOzP9nHS5gM8v5YRLYOl4v+GxuvEdFVwfE7g== X-Received: by 10.200.51.11 with SMTP id t11mr15522058qta.23.1483470758548; Tue, 03 Jan 2017 11:12:38 -0800 (PST) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.157.5.41 with SMTP id 38ls18583321otw.35.gmail; Tue, 03 Jan 2017 11:12:37 -0800 (PST) X-Received: by 10.55.143.195 with SMTP id r186mr68039537qkd.152.1483470757771; Tue, 03 Jan 2017 11:12:37 -0800 (PST) Original-Received: from gondolin.macieira.info (gondolin.macieira.info. [2a01:4f8:d13:f81:21c:14ff:fe01:12a3]) by mx.google.com with ESMTP id m127si33407555qke.66.2017.01.03.11.12.37 for ; Tue, 03 Jan 2017 11:12:37 -0800 (PST) Received-SPF: pass (google.com: domain of thiago@macieira.org designates 2a01:4f8:d13:f81:21c:14ff:fe01:12a3 as permitted sender) client-ip=2a01:4f8:d13:f81:21c:14ff:fe01:12a3; Original-Received: from tjmaciei-mobl1.localnet (unknown [187.34.234.250]) by gondolin.macieira.info (Postfix) with ESMTPSA id B150711B7FF for ; Tue, 3 Jan 2017 11:12:36 -0800 (PST) In-Reply-To: X-Original-Sender: thiago@macieira.org X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of thiago@macieira.org designates 2a01:4f8:d13:f81:21c:14ff:fe01:12a3 as permitted sender) smtp.mailfrom=thiago@macieira.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:30191 Archived-At: On ter=C3=A7a-feira, 3 de janeiro de 2017 08:22:52 BRST m.cencora@gmail.com= wrote: > > How do you know whether a use of enum_cast is compile-time or whether i= t > > is > > runtime? >=20 > I don't know and I don't care. The function should be constexpr to suppor= t > both cases. Well, I think people may care. A constexpr invocation has zero cost at=20 runtime, since it will have failed to convert by producing an error message= ,=20 or it will succeed by becoming a no-op (like static_cast, minus pointer=20 adjustment). But a non-constexpr invocation will have a runtime cost. > What I'd like to hear now is whether anyone else would find such a > functionality useful? > Do you consider it a good idea to put it into C++ standard/library? Maybe you should rename it to mean a check if the value is a valid enumerat= or=20 and drop the "cast" part. --=20 Thiago Macieira - thiago (AT) macieira.info - thiago (AT) kde.org Software Architect - Intel Open Source Technology Center --=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/42463446.MPeEFdAbRV%40tjmaciei-mobl1. .