220 32551 <4df4ee9a-d1e4-40cc-b50b-3109195133fd@isocpp.org> article Path: news.gmane.org!.POSTED!not-for-mail From: Mingxin Wang Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: constexpr ternary (was: Re: relaxing rules for ternary operator. Allow incompatible types.) Date: Sun, 21 May 2017 07:34:08 -0700 (PDT) Lines: 75 Approved: news@gmane.org Message-ID: <4df4ee9a-d1e4-40cc-b50b-3109195133fd@isocpp.org> References: <1b5ee8eb-53df-4e98-af2f-829c7bc2e5b2@isocpp.org> <9770742d-c5de-4a55-869f-ab71231cc775@isocpp.org> <9dbebffff1732ae5966a93b69a836757@kdab.com> <72a1eb41-3713-4602-84c0-e3fce2cadbd4@isocpp.org> <4752662e-21d2-4498-b236-a5dfb7cb2520@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_Part_2200_144066872.1495377248079" X-Trace: blaine.gmane.org 1495377248 9065 195.159.176.226 (21 May 2017 14:34:08 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Sun, 21 May 2017 14:34:08 +0000 (UTC) Cc: zy@miator.net To: ISO C++ Standard - Future Proposals Original-X-From: std-proposals+bncBDNMBNHJWIGBBYGKQ3EQKGQEWYGG4GY@isocpp.org Sun May 21 16:34:04 2017 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-yw0-f197.google.com ([209.85.161.197]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1dCRvo-0002Ei-BJ for gclcip-std-proposals@m.gmane.org; Sun, 21 May 2017 16:34:04 +0200 Original-Received: by mail-yw0-f197.google.com with SMTP id t9sf61170316ywe.12 for ; Sun, 21 May 2017 07:34:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=isocpp-org.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:message-id:in-reply-to:references:subject :mime-version:x-original-sender:reply-to:precedence:mailing-list :list-id:x-spam-checked-in-group:list-post:list-help:list-archive :list-subscribe:list-unsubscribe; bh=DHW91J91Fkqw7SMCle85Jlb/bPtuaNyXd2gowsty5vk=; b=bk9xvlUC+5nLnnAOPXiJl+esBB55oU3yEgI+WcIK0UEX2sVkEph7LmSMDyPZCm7SAz r+O+QCcOx7ULBheJO/9exR2sFnx3nYLEUD8pQr1bMHA+EqGFXmZcoo+3MT6uTuyjw1cq cmqfQiBcSH0RXJltgTVOauwTtgEzNypEB9EnN+f0AiDKdBJMgraw+xP1fGa8QlSl2Lyy b9WJzLJ0w0jczO7UtNsNJdPMyiHS4DxgV14q6pAKZCWVkTFOcNJtLiNK/yxFOjPqZOop bZx6G27gauzpHTgUQVUmwrLOZGweuTLtEHep8FaYeEKTKVLPY2dBk8MUr7Lhp+4pFKCQ K9Wg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:message-id:in-reply-to :references:subject:mime-version:x-original-sender:reply-to :precedence:mailing-list:list-id:x-spam-checked-in-group:list-post :list-help:list-archive:list-subscribe:list-unsubscribe; bh=DHW91J91Fkqw7SMCle85Jlb/bPtuaNyXd2gowsty5vk=; b=OF5czE+Nwa6K32OzFS8Sh+wUIuHIEoE/fkHwKlqGXEeNClzzasP18umZ4upsKrflyV mxcwz5WsxwM5f3xCLpV89nIe0hrWardo0ETjwJY/Lr65X/LbjcQzNyBaQMIB0taxfaYC RL5hSeGyAIr8b1erVKjKaX4cGT/EhWkbG/TLaRlooN2ptzbSaVHPB1H1AJ7qi2vxatc0 Mpfec4EUj15yq2i448oEJcw3WXBcFWquWv7F9mHwqvnPrjYE2uZQ7++dQq+Go5Sry0IK dMADLQa1TuyYcUHvlJ7eHZUv7kqdBxsXcw3A4nQy941tb0e/CMuuwDkIzSnNLuy6sD3U MLWA== X-Gm-Message-State: AODbwcBdX4Z8Df003XCMFK9oHbFPRaKw+JoJBn7Tdn27BlUmZwzCQWu6 rSzK1Bo7/FQFmkJ5 X-Received: by 10.129.161.22 with SMTP id y22mr8916992ywg.166.1495377249358; Sun, 21 May 2017 07:34:09 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.157.17.19 with SMTP id g19ls1922913ote.17.gmail; Sun, 21 May 2017 07:34:08 -0700 (PDT) X-Received: by 10.157.28.130 with SMTP id l2mr391757ota.17.1495377248537; Sun, 21 May 2017 07:34:08 -0700 (PDT) In-Reply-To: X-Original-Sender: wmx16835vv@163.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:32551 Archived-At: ------=_Part_2200_144066872.1495377248079 Content-Type: multipart/alternative; boundary="----=_Part_2201_1919695596.1495377248079" ------=_Part_2201_1919695596.1495377248079 Content-Type: text/plain; charset="UTF-8" If the type cannot be deduced at compile time, then runtime overhead is inevitable. On Sunday, May 21, 2017 at 9:59:43 PM UTC+8, Nicol Bolas wrote: > > On Saturday, May 20, 2017 at 10:54:38 PM UTC-4, Mingxin Wang wrote: >> >> If the condition is not "constexpr", and the types are determined at >> runtime, the "proxies" and the "wrappers" can be used to solve this >> problem. ( >> https://groups.google.com/a/isocpp.org/forum/#!topic/std-proposals/kvkgsHM6wFQ >> ) >> > > So long as you're willing to suffer through needless virtual call > overhead, as well as less obvious code, yes. > -- 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. To view this discussion on the web visit https://groups.google.com/a/isocpp.org/d/msgid/std-proposals/4df4ee9a-d1e4-40cc-b50b-3109195133fd%40isocpp.org. ------=_Part_2201_1919695596.1495377248079 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
If the type cannot be deduce= d at compile time, then runtime overhead is=C2=A0inevitable.

= On Sunday, May 21, 2017 at 9:59:43 PM UTC+8, Nicol Bolas wrote:
On Saturday, May 20, 2017= at 10:54:38 PM UTC-4, Mingxin Wang wrote:
If the condition is not "const= expr",=C2=A0=C2=A0and the types are determined at runtime, the "p= roxies" and the "wrappers" can be used to solve this problem= .. (https://groups.google.com/a/isocpp.org/forum/#!topic/std-proposals/kvkgsHM6wFQ)

So long as yo= u're willing to suffer through needless virtual call overhead, as well = as less obvious code, yes.

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