220 34271 article Path: news.gmane.org!.POSTED!not-for-mail From: Larry Evans Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Idea: Extension of structured bindings to definition of structs Date: Sat, 2 Sep 2017 03:36:17 -0500 Lines: 38 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: text/plain; charset="UTF-8"; format=flowed X-Trace: blaine.gmane.org 1504341334 6948 195.159.176.226 (2 Sep 2017 08:35:34 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Sat, 2 Sep 2017 08:35:34 +0000 (UTC) User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.1 To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBDAYTI72VMGRBSO2VHGQKGQE623YDYY@isocpp.org Sat Sep 02 10:35:19 2017 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-wr0-f199.google.com ([209.85.128.199]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1do3tc-0000vj-Mu for gclcip-std-proposals@m.gmane.org; Sat, 02 Sep 2017 10:35:16 +0200 Original-Received: by mail-wr0-f199.google.com with SMTP id p37sf641653wrc.9 for ; Sat, 02 Sep 2017 01:35:23 -0700 (PDT) ARC-Seal: i=2; a=rsa-sha256; t=1504341323; cv=pass; d=google.com; s=arc-20160816; b=CqEpKiQQtsjdGWDXp9I68LmyR3Q6QBUpzUPdG99erebC7XzSN1Th1ntY3hkyezvsL8 Hili9+5Yo+HQ4w1w58asYeE4V595zPEjDCgHvmok/8cdEO7QyvJ7nZxXCLLwJ1/OLFuL b2Jp+fLgLNdWkx16sHp3B4K+ChzbKSVF73M1K3jy2c/cpag9vObC7VR9qLcpJIrKzyBg hYLfFSn6g9SJmbWqU4/GLz7kzbshw5VSWtAqMMGoz+xHc0WKe1v2DBcpYzsZt2DpdnJB oqBeOSzonEvSwTI/Ola966mhtNbmryO78G73FHypJGvLIAXsSMZYf2Lu9Y22KP8P6WCe eDQg== ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-unsubscribe:list-subscribe:list-archive:list-help:list-post :list-id:mailing-list:precedence:reply-to:content-language :in-reply-to:user-agent:mime-version:references:message-id:lines :date:subject:from:to:arc-authentication-results :arc-message-signature:dkim-signature:arc-authentication-results; bh=0MoCrlfqz2d6eKSzxpPttctTHrPcdg3FAaGdGXOG7lE=; b=bCRgyVa/GKFGPRv9eL35B76jn3u7qsc2MGCw0nWqoOZXMOFRa8mNGAesPGmPPf1ZH0 gVWpw7iHvI3CeN5FNmeSTMpyRx7710hL+xL+Qn9DQ4FvxLPzZkSToVunF7eqKx9flXIX 0otkiePqBcnuPOkjq2svASPWKeguZ/ZtMS54CvJY+AuTbAJJL9TxC8lyTfZw1QbYq000 xmWr2/83KQu3pZl3a3Xgs/88m34GsZgIOFPxbedvFq7PcEhpGBLrBr9kfRgUkOCNnvVG nsgO6UP1kQfWe1/yGekob/7XevMaHi8EFzIh25Zx3vi0MFhe2W23vna9YD1hZpWnfUqH hq5g ARC-Authentication-Results: i=2; mx.google.com; spf=neutral (google.com: 195.159.176.226 is neither permitted nor denied by best guess record for domain of gclcip-std-proposals@m.gmane.org) smtp.mailfrom=gclcip-std-proposals@m.gmane.org 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 :user-agent:in-reply-to:content-language:x-original-sender :x-original-authentication-results:reply-to:precedence:mailing-list :list-id:list-post:list-help:list-archive:list-subscribe :list-unsubscribe; bh=0MoCrlfqz2d6eKSzxpPttctTHrPcdg3FAaGdGXOG7lE=; b=FmmCkr66MxotXpJw8RbmTLUupcjjaeWxtTNN1UwB2v7Tf9Lm0Ww5jSJd3MbVVcqe+4 0gRV4uxTytlnQIyIczI7BVQ/kafh0hM2FVWrxCtBJE1od3G3agXdlxs8jUgRejUfMbZn w5O6SrTe4hYm6EPVSxWv40v3a2iduLWLYGf/sMgak+eudkaXZE38wH7u+SWwxhQITmVZ mUEy82DD+6JVscEYDbe3ZRejP1UMFlbmDrwQ4uKE/MfUp5oVEfLit2/ZYR4lOdD7ei7Y hEVI0FwEGaOUboQIiS0dyEaU4VApaQOdL12yuLsPTqqe2qqpTJgONPh7JRR0NlUzyXS5 i0Rg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:to:from:subject:date:lines:message-id:references :mime-version:user-agent:in-reply-to:content-language :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=0MoCrlfqz2d6eKSzxpPttctTHrPcdg3FAaGdGXOG7lE=; b=CIoLSNIn09KVx4bOIHF7DCh3BHIK2p+WLO3ErsaQzB9Lg7rh9cQaLWsYcBTSce5W2x HCQbqzby31hRFzQ7OI5YKCAbz+4Wpw1DlXk1djRYmwf40g2RArDdPFQ+qtaWkoASWdlS dZOxomob2pDu/xapwvZMvKjQQw7CPhEDKhQmb9zLgNhgYEV7MRr0JEPsZwM/OWrGqbLq L4nM5uVMSd0whkQQ5Sh/1+z4B9fr3klczSWABZqNlbTr606Bh9ySGcQWUKBBbIPVBGB2 j8g3hGF2QaEQw2tYJA5A+WouYkyowhV09Ahsx1ocXy9sisCyyhMqHKRrJGGFe1n56Qis X-Gm-Message-State: AHPjjUgKm/iFp4M1gk66FVjq/e8JcKYwSM+XhVz+XnFaBrjlIbvY40+U 7qiS13h1Scmz7Q== X-Google-Smtp-Source: ADKCNb5VYcvqBd8qebT467MZdLNfRspTiQA2pEGFLya4SEpprmJM5lNtTYkJH+tas5Q0bTmTG1kEkw== X-Received: by 10.28.11.131 with SMTP id 125mr62231wml.20.1504341323666; Sat, 02 Sep 2017 01:35:23 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.46.21.10 with SMTP id s10ls86902ljd.51.gmail; Sat, 02 Sep 2017 01:35:21 -0700 (PDT) X-Received: by 10.25.99.68 with SMTP id x65mr2045438lfb.41.1504341321572; Sat, 02 Sep 2017 01:35:21 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1504341321; cv=none; d=google.com; s=arc-20160816; b=T0sC38k2qsDKPCQp+jy9hSoGclV+Vib4nNv7EFS8EWoBG2qH9SKC+oyW2DvKZpf15H EdIU7p5pVHlT50XM2b137EYgTsnYXcIsyf7qdEfPt5RpJ4987kLeGPXPaZOUBrDTClUB nzZb+gR3QNGOTxo+Uiye8AaQpTZGcCQNAeKbWTuvkYYpvabN6SqPXOzToPYo3sswNPGh Vf8dBEdkEHJuEeFg/F8UxTLWL5LYh6dyGeXU0eO6OwqoOo+t2FD12uEF3LdUnmG+cZ11 4VuSZTL3cO7rJrL0zRlPy2jk65wGE/jWiCtcxgUgBS9H3RmJcBWb8W95Zv78+qld3T4K ANwg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=content-language:in-reply-to:user-agent:content-transfer-encoding :mime-version:references:message-id:lines:date:subject:from:to :arc-authentication-results; bh=jpq3WDzU7vNKBugHQJu5YQC1fJWKSkxF/O0i/EZbYRM=; b=umgUQGjE+oFRr+ngGdFrNMuG/km3JJflYC9v8Or9PFHp5DBBu7x7Vylajbi6LR8Y8c lO5Rcpppl2r6zvUfXxaGUTCzMLbfS6jfKGPUQZGsvi801cuqObhLqWoT5VNO2xvDB4BE QagX1JtsR5QEHzJM7Sa2KRDa4Afu4Jxckm/dDhlALTRo+DqXeWUVKcYRq7L62e15Qor3 VxolTW2lZvoL1xyxDj1sxNvXGPW/kOq7ihW1FGKnnesUrTzQlR+9gI1qk5Dd74kZwc09 3Evaq12Qo6xUJkieoGbBIzTFe9RawzWQAbKT6mLPhyBORlLh4edlzFaiVZUizQD4uN1k yy4A== ARC-Authentication-Results: i=1; mx.google.com; spf=neutral (google.com: 195.159.176.226 is neither permitted nor denied by best guess record for domain of gclcip-std-proposals@m.gmane.org) smtp.mailfrom=gclcip-std-proposals@m.gmane.org Original-Received: from blaine.gmane.org ([195.159.176.226]) by mx.google.com with ESMTPS id 26si776215ljw.279.2017.09.02.01.35.21 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sat, 02 Sep 2017 01:35:21 -0700 (PDT) Received-SPF: neutral (google.com: 195.159.176.226 is neither permitted nor denied by best guess record for domain of gclcip-std-proposals@m.gmane.org) client-ip=195.159.176.226; Original-Received: from list by blaine.gmane.org with local (Exim 4.84_2) (envelope-from ) id 1do3tL-0000C9-QR for std-proposals@isocpp.org; Sat, 02 Sep 2017 10:34:59 +0200 X-Injected-Via-Gmane: http://gmane.org/ Original-Lines: 31 Original-X-Complaints-To: usenet@blaine.gmane.org In-Reply-To: Content-Language: en-US X-Original-Sender: cppljevans@suddenlink.net X-Original-Authentication-Results: mx.google.com; spf=neutral (google.com: 195.159.176.226 is neither permitted nor denied by best guess record for domain of gclcip-std-proposals@m.gmane.org) smtp.mailfrom=gclcip-std-proposals@m.gmane.org 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:34271 Archived-At: On 08/30/2017 10:16 AM, Nevin Liber wrote: > On Wed, Aug 30, 2017 at 2:59 AM, Eyal Rozenberg > wrote: > >> You would be using an unnamed struct for the same reason you use an >> "unnamed type" for non-struct variables with auto. We write: >> >> auto x = expr; >> > > Even though you don't spell it out, that type already has a name. auto > doesn't create a new type. > > You are proposing yet another syntax to create a new type. As for its use, > about the only thing you can do with it is pass it to a template function > (or equivalent). That use seems fairly marginal. You need much better > usage examples for motivation. > Boost spirit has a macro, BOOST_FUSION_ADAPT_STRUCT, which maps a tuple to a struct, as explained here: http://ciere.com/cppnow15/x3_docs/spirit/tutorials/employee___parsing_into_structs.html What the OP is proposing *seems* to obviate the need for BOOST_FUSION_ADAPT_STRUCT. That's one real world motivation example, IIUC. -regards, Larry -- 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/oodqev%24t5m%241%40blaine.gmane.org. .