220 23852 article Path: news.gmane.org!not-for-mail From: Matthew Woehlke Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: RFC: Unpacking tuples to value sequences Date: Tue, 19 Jan 2016 11:31:22 -0500 Lines: 36 Approved: news@gmane.org Message-ID: References: <6f3ece34-e302-4d95-afd0-4c1924e8a780@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 1453221101 27079 80.91.229.3 (19 Jan 2016 16:31:41 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Tue, 19 Jan 2016 16:31:41 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBC37LBFWUIFBBYWJ7G2AKGQEXFHF5NI@isocpp.org Tue Jan 19 17:31:32 2016 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-lb0-f200.google.com ([209.85.217.200]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1aLZBr-0004Uu-TQ for gclcip-std-proposals@m.gmane.org; Tue, 19 Jan 2016 17:31:31 +0100 Original-Received: by mail-lb0-f200.google.com with SMTP id dx9sf64386267lbc.3 for ; Tue, 19 Jan 2016 08:31:31 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=isocpp-org.20150623.gappssmtp.com; s=20150623; h=to:from:subject:date:lines:message-id:references:mime-version :content-type:user-agent:in-reply-to: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=b4xT6i1H8H3y4SWiF4Hc4CbUzCiysEFz4F5TwjrYhEY=; b=X4kzxLBaxNuPldN5KJWJKONoKkF2PQEiV2vlVLM/k4RomMOa9eS6bEaRWm1nBJj3/r Xxkvd9+HlNCdbCuOYeP9jONlZHSARFaufSzhjqQ3LOxL2iZWRBqWLIFiyPMTgeouyKsa 20IcX/I2kOESwJVicYY8aZTqEvG2xm1ZOD/7MEiX+g8K8TlCBDGOppAJrR+uT7scwrBZ ndOyHiZ9MlD7nb2Rbe7fl+S+f6Alx/jivCJLVfa6h7gDhWB4Bb2vhSGFDv2xMfCe3ZQl kfvq7w6idQqxeKI4tE1BzWVWrXg4rqM8o7aLOuubU2s5v7R3Rzz+ZdOT+lPaIqib2xwF kRa X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:to:from:subject:date:lines:message-id:references :mime-version:content-type:user-agent:in-reply-to: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=b4xT6i1H8H3y4SWiF4Hc4CbUzCiysEFz4F5TwjrYhEY=; b=VNMJF+pRTiLNaGsCpmQ/QimuAxX6DmVHuEIWwto2iR5rnJPJWGnBOuq92TztE+nAmx w4BDcqhhet6R/9/HmUCNwGNQcBchas4rNbL5fbmBntaZEW6B6C2b7muoHgdANPvxZhlI whc6P3pSOSXFObqaOiU5U4sxDZlGEL5o8rMRtMS53gX+MwreHBgSR8DxJZ98DZ5s6u+w ase47t6a2cGWlvQFdEkrTUX867hkRf9ch7ifhPil3G9KuhZb9oTuVzerwV5C28xA2TG6 8wKaHG+/p7Zbysh+3mOvixMUqh6LZETGWdWnZx+G41J1fGWGjEqQEr73FH8QUKy+wP29 X-Gm-Message-State: ALoCoQlYGOreoqHScHnrwK9aI/AzaP9QHGq9L7XloeN7so/eVtTq/gxtkQLcUZPw6TsGVyP4jl1tr4yFXvM2heLhvO9F+Jwt6w== X-Received: by 10.194.178.129 with SMTP id cy1mr4091857wjc.2.1453221091523; Tue, 19 Jan 2016 08:31:31 -0800 (PST) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.25.144.140 with SMTP id s134ls634800lfd.91.gmail; Tue, 19 Jan 2016 08:31:30 -0800 (PST) X-Received: by 10.112.168.227 with SMTP id zz3mr4512692lbb.10.1453221090023; Tue, 19 Jan 2016 08:31:30 -0800 (PST) Original-Received: from plane.gmane.org (plane.gmane.org. [80.91.229.3]) by mx.google.com with ESMTPS id j134si15140878lfe.165.2016.01.19.08.31.29 for (version=TLS1 cipher=AES128-SHA bits=128/128); Tue, 19 Jan 2016 08:31:29 -0800 (PST) Received-SPF: pass (google.com: domain of gclcip-std-proposals@m.gmane.org designates 80.91.229.3 as permitted sender) client-ip=80.91.229.3; Original-Received: from list by plane.gmane.org with local (Exim 4.69) (envelope-from ) id 1aLZBp-0004Tv-9Y for std-proposals@isocpp.org; Tue, 19 Jan 2016 17:31:29 +0100 Original-Received: from tripoint.kitware.com ([66.194.253.20]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Tue, 19 Jan 2016 17:31:29 +0100 Original-Received: from mwoehlke.floss by tripoint.kitware.com with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Tue, 19 Jan 2016 17:31:29 +0100 X-Injected-Via-Gmane: http://gmane.org/ Original-Lines: 27 Original-X-Complaints-To: usenet@ger.gmane.org X-Gmane-NNTP-Posting-Host: tripoint.kitware.com User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 In-Reply-To: <6f3ece34-e302-4d95-afd0-4c1924e8a780@isocpp.org> X-Original-Sender: mwoehlke.floss@gmail.com X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of gclcip-std-proposals@m.gmane.org designates 80.91.229.3 as permitted sender) smtp.mailfrom=gclcip-std-proposals@m.gmane.org; dmarc=fail (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-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:23852 Archived-At: On 2016-01-19 10:40, Nicol Bolas wrote: > auto ...thing1 = func([*]f, [*]g)...; I alluded to this in my other reply, but I think it bears repeating... what does this (RHS) mean? - { func(f<0>, g<0>), func(f<1>, g<1>) } - { func(f<0>, f<1>, g<0>), func(f<0>, f<1>, g<1>) } - { func(f<0>, g<0>, g<1>), func(f<1>, g<0>, g<1>) } - func(f<0>, f<1>, g<0>, g<1>) I could legitimately want *any* of those. Conflating concepts (template argument packs and value sequence unpacking of tuple-likes) makes it impossible to specify which. Not to mention that I'm not convinced the syntax isn't overly obtuse. If, instead, we have apply_each (and zip), I can be precise: - apply_each([](auto p){return func([*]p);}, [*]zip(f, g)) - apply_each([](auto v){return func([*]f, v);}, [*]g) - apply_each([](auto v){return func(v, [*]g);}, [*]f) - func([*]f, [*]g) Now there is no ambiguity as to my intent. -- Matthew -- --- 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. Visit this group at https://groups.google.com/a/isocpp.org/group/std-proposals/. .