220 26216 <0aa49f06-08b0-433a-a897-720140eb7097@isocpp.org> article Path: news.gmane.org!not-for-mail From: Greg Marr Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: statement folding on variadic templates parameters pack Date: Wed, 8 Jun 2016 08:11:21 -0700 (PDT) Lines: 128 Approved: news@gmane.org Message-ID: <0aa49f06-08b0-433a-a897-720140eb7097@isocpp.org> References: <1e3daa7c-e10a-4589-8118-26f47bc1a0df@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_Part_649_1412130046.1465398681382" X-Trace: ger.gmane.org 1465398948 659 80.91.229.3 (8 Jun 2016 15:15:48 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Wed, 8 Jun 2016 15:15:48 +0000 (UTC) To: ISO C++ Standard - Future Proposals Original-X-From: std-proposals+bncBDEZH3XFPIIJV27AXICRUBEDI55JG@isocpp.org Wed Jun 08 17:15:44 2016 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-it0-f71.google.com ([209.85.214.71]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1bAf8e-0004EW-2I for gclcip-std-proposals@m.gmane.org; Wed, 08 Jun 2016 17:11:24 +0200 Original-Received: by mail-it0-f71.google.com with SMTP id z189sf21849224itg.2 for ; Wed, 08 Jun 2016 08:11:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=isocpp-org.20150623.gappssmtp.com; s=20150623; h=date:from:to: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=bZFPnZ6zJpVQwS0rcu3Bs3v5vErDY6WMLbdc4qU2chQ=; b=XryYJLPgYqa3weAZ0u3ohSgQdvWU4YAf3HqI+dsINOZaWXN7maqRnOYc3t0oD61UxV q7x2zIaYAcG8/5Tq3uNOk4NF3uPHVXgu6tat0gGJG+Fw4kKkn56eBs0Axxk0TGlF3lox aP6+ccPAqOQcdOHL4cvtBFA/RO+ZaPGptRjF2zeBYw8VZ2RnQ3R0LKOC9fSFmo+ZonTx IVG3KW6U6h9Bf/t/nEK7mv7hjHGdpiNxr190u5aDR0n//6hg0ouRfA0r7s7DYDEGs5dG 5HogPoGnZzbX/zv9/QnQvP88Igr4RHUTSmKjFE86nrq8JXCSxd86ZToArjmT3Y2qK1Ej 0PbQ== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=date:from:to: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=bZFPnZ6zJpVQwS0rcu3Bs3v5vErDY6WMLbdc4qU2chQ=; b=x3YZmjwQPaRN6jy2EX83vPA9HTPIzR1JZKAGMBa/lC9NSCZTRf364CxrwQNaBNYvRC do8gpCNNuE8Nb4xkrAxdtgcZ75emYh0mh2BAN06+6KFgsDZUb2JwtCZkKrCKcWLXk4T4 XjCZpe4XsMewUS9tSYZTtlVcJVbHsBqjtSEURmL9Csm73evPnfu7YqLTuFrOT1NpDhR0 8humtXupiPDl+lLNl0tSdW3ehk7728x8qFAnsZDxBBNdhVLBGq34E7VHY2bkFLItZETl Aqw7zQbBUIxfxCTpmrAraj9u/9COP9PCLpuMAFO2+Tam0iU4M9BOuoSbUmyN5zAv8zMe vB1A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:date:from:to: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=bZFPnZ6zJpVQwS0rcu3Bs3v5vErDY6WMLbdc4qU2chQ=; b=d3MMKDCLh3zxB5t5i+tD6j019gSKKsWHXUmt88Bsuy7iyV1vdqUVdPLnX7LBfxufZ7 +6fkMp+QQ/lwyjlgxZakTPbz+px8cO2n2TMyvgkARQFYUHBdR1bOqsqY7Z0GdujAfe+p mMYXkfp3DTEixUxRR6zexFQ0TmZ8vAgHQarh2IMO0TZXZQP3Znl7iy5WEXFpJPmfktZr RkYoG03TQqKFuY5q2Kq4t3kWUZroTaCvyH/BjXV9Y8tqM4h7YaRTR3k90iC+tja66Pf9 aL0pbntIrFq6dNfE+rrjEWlBJY90me5mHZblDX+o2mgrwIbEzWiPQ1e7iZadozqQySoF slOw== X-Gm-Message-State: ALyK8tLniRIzCBnhg3k3SkgEKoiHqRjssgHzPv2e7ITgKWZHrwADhX0mowT5LfLruYNlig== X-Received: by 10.36.118.79 with SMTP id z76mr5951844itb.1.1465398683195; Wed, 08 Jun 2016 08:11:23 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.107.174.7 with SMTP id x7ls162462ioe.53.gmail; Wed, 08 Jun 2016 08:11:22 -0700 (PDT) X-Received: by 10.36.103.17 with SMTP id u17mr324146itc.4.1465398682206; Wed, 08 Jun 2016 08:11:22 -0700 (PDT) In-Reply-To: <1e3daa7c-e10a-4589-8118-26f47bc1a0df@isocpp.org> X-Original-Sender: gregmmarr@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:26216 Archived-At: ------=_Part_649_1412130046.1465398681382 Content-Type: multipart/alternative; boundary="----=_Part_650_1948991266.1465398681383" ------=_Part_650_1948991266.1465398681383 Content-Type: text/plain; charset=UTF-8 On Wednesday, June 8, 2016 at 10:14:50 AM UTC-4, Sergey Vidyuk wrote: > > Expression folding on a variadic template parameters pack are great and > allows to write internal function stuff inside a function instead of > writing some recursive template code which is required to be moved outside > of the function. But when one want to repeat some statement for every > element of a parameter pack recursive templates or abusing of coma operator > folding are stil the only options. After facing this issue several times I > start to realize that it would be great to have the following extension to > the C++11 range-for syntax: > Have you seen Sean Parent's for_each_argument? template void for_each_argument(F f, Args&&... args) { [](...){}((f(std::forward(args)), 0)...); } There was even a CppCon 2015 talk about it https://www.youtube.com/watch?v=2l83JlqkzBk -- 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/0aa49f06-08b0-433a-a897-720140eb7097%40isocpp.org. ------=_Part_650_1948991266.1465398681383 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
On Wednesday, June 8, 2016 at 10:14:50 AM UTC-4, Sergey Vi= dyuk wrote:
Ex= pression folding on a variadic template parameters pack are great and allow= s to write internal function stuff inside a function instead of writing som= e recursive template code which is required to be moved outside of the func= tion. But when one want to repeat some statement for every element of a par= ameter pack recursive templates or abusing of coma operator folding are sti= l the only options. After facing this issue several times I start to realiz= e that it would be great to have the following extension to the C++11 range= -for syntax:

Have you seen Sean P= arent's for_each_argument?

template <class F, class... Args>void for_each_argum= ent(F f, Args&&... args) {<= br>=C2=A0[= ](...){}((= f(<= span style=3D"color: #000;" class=3D"styled-by-prettify">std::forward<Args>(args)), 0)...);<= /span>
= }


=
There was even a Cp= pCon 2015 talk about it

https://www.youtub= e.com/watch?v=3D2l83JlqkzBk

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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/0aa49f06-08b0-433a-a897-720140eb7097= %40isocpp.org.
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