220 36330 <1a84e87b-c045-408c-9828-b1aba2185a0a@isocpp.org> article Path: news.gmane.org!.POSTED!not-for-mail From: Nicol Bolas Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Now that the std::forward alternative has been rejected Date: Sun, 24 Dec 2017 20:28:05 -0800 (PST) Lines: 215 Approved: news@gmane.org Message-ID: <1a84e87b-c045-408c-9828-b1aba2185a0a@isocpp.org> References: Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_Part_14608_921327778.1514176085868" X-Trace: blaine.gmane.org 1514175972 12815 195.159.176.226 (25 Dec 2017 04:26:12 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Mon, 25 Dec 2017 04:26:12 +0000 (UTC) Cc: mihailnajdenov@gmail.com To: ISO C++ Standard - Future Proposals Original-X-From: std-proposals+bncBCEKFTV6ZUMBBV74QHJAKGQEJ47WUEA@isocpp.org Mon Dec 25 05:26:08 2017 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-ua0-f198.google.com ([209.85.217.198]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1eTKL0-0002sh-7Z for gclcip-std-proposals@m.gmane.org; Mon, 25 Dec 2017 05:26:06 +0100 Original-Received: by mail-ua0-f198.google.com with SMTP id 7sf21072327uap.5 for ; Sun, 24 Dec 2017 20:28:09 -0800 (PST) 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:list-post:list-help:list-archive:list-subscribe :list-unsubscribe; bh=s7qfiJka4JzSVEp4mggbH0I+OXm8rUbpGpUH6AqXLs4=; b=XeWSqNKKZBaJeo9TZHxc2mmr8PpCtimlE8O85l3E3WJVQX68+R3ZRZXu1a+FYeYAZk 46yeeFKhVu1+kfa0zKbhSc3746R//vsh4iM90SLwdU5r05wTRoLlwmnGr9Dy/WLJI6RP aTqYt+40E2T6+XUeSitUOj3sv99GQnulPzHzwIog9v2pTq32HPI3pXufLpXSvbnq9a07 4PtlqNlzkANVkXqLC9+ipF2U9EaB7h0w1nPKHkFUVfh1jYOZeTJa+ruage6MXDYTcojj SzNQ9Yl9wGi00JMzTpblpt1fmMTYmTq2wr02gmwRi6eJW26FY/2p8tlrF8bui2+Y9kpH BD4A== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:message-id:in-reply-to:references:subject :mime-version:x-original-sender:reply-to:precedence:mailing-list :list-id:list-post:list-help:list-archive:list-subscribe :list-unsubscribe; bh=s7qfiJka4JzSVEp4mggbH0I+OXm8rUbpGpUH6AqXLs4=; b=ALvFdqI/OGx/traEAaRSk7THT5hM/xHrzwTHryo+QanF+68oCnD5IHwZ7Ks9xK1J52 8ysB9XlhzyII4U/xCCsIsnViyAiCm1v44+974/rLX50dJPWnZXtOSDhbf3CcNqchjFPE uhr8lEd8In0mrp+R4Kdg3b05vHYtNkWUuoezABjW8QIpaOestf7ZjZLUY+TOOi36F4ys Pj+kAi8tuY3xLItz0mn+HiXPbzYouvYMtTf0vTWoB8topwOsWD2LGV6vuJH1k1EIkwxW EmxV1dhj/30KhAjEJ/ZeDnj2/HkS95trApNMduHV/RPuF4bxe910kehDqaJpEe3OG4HM 3fKQ== 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=s7qfiJka4JzSVEp4mggbH0I+OXm8rUbpGpUH6AqXLs4=; b=nd8L3pS/pDWmoPqJ88ucbYNuou+LGtWy9zhUL7XPm5SK/HbT3EhIg+f2hQbX/4H7gX KhgKRtP7pUw6lFMWo8GEr9deE3EDduKSl4BRA6pCl0CNJjSOdhiRKTLQdMeVanae9yxN k78bXy5rUI4Ednp9PWEjFkesof2VoEewLz6EoQLnSXPcE/vX85vHFN2alNaQmD0eDofH /P8BgnYVlIv5tekw8+Y/ixmKB6j5UkazQFyPEhDV5coHM12cXNZsxJNL8XnV3m4nEReh IYhtRgwjnt3kfKSeAzrmIKk8RJLMVxzpBcIDeYxyHne3hbcY810H9MOIBLLKq/Ps9R1W b/7w== X-Gm-Message-State: AKGB3mKwEVK5cj7+STVGBC3lGrI10pCxEMz5zioQJJ/DkmUAgE0slt0d Bor4Tnwo/3UxaUOXkEX6fZijzA== X-Google-Smtp-Source: ACJfBovlaqoqK6l5zzZMXhFg6dE+gbFfQ+LiMiR72Gj4/FkVYNPNZaazNc/0oJEMe5N0gHCL1TCsWQ== X-Received: by 10.31.84.1 with SMTP id i1mr10198435vkb.86.1514176088756; Sun, 24 Dec 2017 20:28:08 -0800 (PST) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.176.89.194 with SMTP id k2ls41640uad.10.gmail; Sun, 24 Dec 2017 20:28:07 -0800 (PST) X-Received: by 10.31.165.202 with SMTP id o193mr1961279vke.9.1514176086477; Sun, 24 Dec 2017 20:28:06 -0800 (PST) In-Reply-To: X-Original-Sender: jmckesson@gmail.com Precedence: list Mailing-list: list std-proposals@isocpp.org; contact std-proposals+owners@isocpp.org List-ID: X-Spam-Checked-In-Group: std-proposals@isocpp.org 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:36330 Archived-At: ------=_Part_14608_921327778.1514176085868 Content-Type: multipart/alternative; boundary="----=_Part_14609_111628405.1514176085868" ------=_Part_14609_111628405.1514176085868 Content-Type: text/plain; charset="UTF-8" On Sunday, December 24, 2017 at 8:17:30 PM UTC-5, bastie...@gmail.com wrote: > > On Sunday, December 24, 2017 at 9:47:30 AM UTC+1, mihailn...@gmail.com > wrote: >> >> Hello, I read >> >> the proposal "Forward without forward" has been rejected. >> >> Now, can we please reconsider fixing forward "the right way" even if it >> involves hacks? >> >> And by "the right way" a mean, of course, let the template param be >> omitted. >> >> Why is the right way? Multiple reasons: >> >> >> 1. Preserve the API taught for close to 10 years now. >> >> actually this is false.std::forward without template param is valid and > your change would change its meaning. > >> >> 1. Remove confusion for EVERYONE learning C++11+, be at a beginner or >> advanced user. >> 2. The param is confusing on its own (to a beginner) - should I pass >> T or T&&, what happens if I pass const T, const T&&, T*? Do I really have >> options here?!? Or Just One Right Param?!?! >> >> std::forward is fairly easy to explain to a beginner. > No, it's not. It's easy to tell a beginner what they have to do and when they have to do it. But explaining what it actually is doing (beyond simplistic "it's forwarding the parameters") is not easy. But even if it wasn't the case, cases where std::forward is required are > not for beginners (library writing, etc...). > Nonsense. Writing passthrough functions should be in* everyone's* toolkit, not just "library writers". Thinking like that is what makes people think that template metaprogramming is OK, because regular C++ programmers shouldn't want to do things like iterate over things at compile time or somesuch. Making the powers of the language more accessible is not a bad thing. >> 1. The param is an ugly nightmare to pass in [](auto) {} scenario >> >> C++20 has template parameter for lambda so this is no longer a valid > issue. > Which only trades one verbosity for another. [](auto&&... args) {return some_func(std::forward(args )...);} vs. []