220 34296 article Path: news.gmane.org!.POSTED!not-for-mail From: Nevin Liber Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Re: Idea: Extension of structured bindings to definition of structs Date: Mon, 4 Sep 2017 14:04:45 -0500 Lines: 82 Approved: news@gmane.org Message-ID: References: <59dcbbbc-c536-4b7b-9c88-0638fb0cd58a@technion.ac.il> <7b9bf263-d3ca-42bf-aed6-4c7606782a28@isocpp.org> <1762295.OciJaA9sdk@tjmaciei-mobl1> <74349bfe-bb5a-a2ce-4142-5d46103d1d9f@technion.ac.il> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: multipart/alternative; boundary="f403045e373a18ace5055861cba2" X-Trace: blaine.gmane.org 1504551959 4658 195.159.176.226 (4 Sep 2017 19:05:59 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Mon, 4 Sep 2017 19:05:59 +0000 (UTC) Cc: "std-proposals@isocpp.org" To: Eyal Rozenberg Original-X-From: std-proposals+bncBCE35H5S6IDBB56HW3GQKGQEOHPUJNI@isocpp.org Mon Sep 04 21:05:38 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 1dowgU-0007yL-MY for gclcip-std-proposals@m.gmane.org; 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[2607:f8b0:400e:c00::232]) by mx.google.com with ESMTPS id g1si5931874pln.738.2017.09.04.12.05.27 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 04 Sep 2017 12:05:27 -0700 (PDT) Received-SPF: pass (google.com: domain of nliber@gmail.com designates 2607:f8b0:400e:c00::232 as permitted sender) client-ip=2607:f8b0:400e:c00::232; Original-Received: by mail-pf0-x232.google.com with SMTP id e199so2612377pfh.3 for ; Mon, 04 Sep 2017 12:05:27 -0700 (PDT) X-Received: by 10.99.151.2 with SMTP id n2mr1433586pge.452.1504551926015; Mon, 04 Sep 2017 12:05:26 -0700 (PDT) Original-Sender: nliber@gmail.com Original-Received: by 10.100.133.80 with HTTP; Mon, 4 Sep 2017 12:04:45 -0700 (PDT) In-Reply-To: X-Original-Sender: nevin@eviloverlord.com X-Original-Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=eoTRNgEM; spf=pass (google.com: domain of nliber@gmail.com designates 2607:f8b0:400e:c00::232 as permitted sender) smtp.mailfrom=nliber@gmail.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:34296 Archived-At: --f403045e373a18ace5055861cba2 Content-Type: text/plain; charset="UTF-8" On Mon, Sep 4, 2017 at 9:16 AM, Eyal Rozenberg wrote: > I'm not actually suggesting a new way to create a type. The type is > created anyway if I write: > > struct { > decltype(std::get<0>(get_car_parts())) engine; > decltype(std::get<0>(get_car_parts())) dashboard; > decltype(std::get<0>(get_car_parts())) stickshift; > } car_parts = get_car_parts(); > Syntactic sugar or not, what can you do with an object of that type? You can either: - Pass it to a templated function - Capture it in a lambda As I stated before, that usage seems fairly marginal and not worth a language feature. -- Nevin ":-)" Liber +1-847-691-1404 -- 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/CAGg_6%2BMCgpaOxQBm1ees1bCJVWrh7%3DqWWkVKWZu3DmeMO6TvMA%40mail.gmail.com. --f403045e373a18ace5055861cba2 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
On Mon, Sep 4, 2017 at 9:16 AM, Eyal Rozenberg <ey= alroz@technion.ac.il> wrote:
I'm not actuall= y suggesting a new way to create a type. The type is created anyway if I wr= ite:

=C2=A0 struct {
=C2=A0 =C2=A0 =C2=A0 decltype(std::get<0>(get_car_parts())) engi= ne;
=C2=A0 =C2=A0 =C2=A0 decltype(std::get<0>(get_car_parts())) dash= board;
=C2=A0 =C2=A0 =C2=A0 decltype(std::get<0>(get_car_parts())) stic= kshift;
=C2=A0 } car_parts =3D get_car_parts();

Syntactic sugar or not, what can you do with an object of that type?=C2=A0= You can either:
  • Pass it to a templated function
  • = Capture it in a lambda
As I stated before, that usage seems f= airly marginal and not worth a language feature.
--
=C2=A0Nevin ":-)" Liber=C2=A0 &l= t;mailto:nevin@= eviloverlord.com> =C2=A0+1-847-691-1404

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