220 31878 <75b1126c-0292-44dc-973a-c903d31b87ec@isocpp.org> article Path: news.gmane.org!.POSTED!not-for-mail From: TONGARI J Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: This variable should not be named: an identifier (not) to remember Date: Wed, 29 Mar 2017 08:23:27 -0700 (PDT) Lines: 100 Approved: news@gmane.org Message-ID: <75b1126c-0292-44dc-973a-c903d31b87ec@isocpp.org> References: <985b9b2a-c734-45eb-95f4-db4dc0d309a1@isocpp.org> <7EF863A1-1454-4116-9164-676FF19BF923@gmail.com> <58DA6B66.2010307@gmail.com> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_Part_1525_1771935987.1490801007373" X-Trace: blaine.gmane.org 1490801017 27557 195.159.176.226 (29 Mar 2017 15:23:37 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Wed, 29 Mar 2017 15:23:37 +0000 (UTC) To: ISO C++ Standard - Future Proposals Original-X-From: std-proposals+bncBCC3NA775MLBB35C57DAKGQEBU6XKHA@isocpp.org Wed Mar 29 17:23:33 2017 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-vk0-f72.google.com ([209.85.213.72]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1ctFRT-0005mg-6W for gclcip-std-proposals@m.gmane.org; Wed, 29 Mar 2017 17:23:23 +0200 Original-Received: by mail-vk0-f72.google.com with SMTP id z204sf7083773vkd.16 for ; Wed, 29 Mar 2017 08:23:29 -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=PEKadXCD5QWMWmrWLft2JHaTmI0a2hGNW89Pm46Xi5U=; b=Wb5ln9itP7Xs4PVhuOGoOmBOzPqZUKju0742W28VzJwbUI5x2y/zxnoWVYadPfKUDn hC846TEYw0CeuKgSe97ZcXh2dqoMQ7398H14grL0AzF026tbP5qMOH7hY/TmlGpGGyoj eXycCyp83Tse9G654G3MGUOVa2sFTOGie0M8Vb2xewqu8Ke7xZJwefKGIipGNpOnmInA g+an2QqqUl1mpMKmMvVqQNK0fz8G8OxOK3njPDQ6jrk0wxdflYqUchRERADk4aolvZRF +0UmfUk7YRh3eDORdhhf92dOP3b+11xC0o2sQyQ63f3NvFN6ya1LEKcoKcdmT3h2F6K+ 1pNw== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; 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=PEKadXCD5QWMWmrWLft2JHaTmI0a2hGNW89Pm46Xi5U=; b=BLgCGSLqQ1nPt+5Dg/6RGXY0A+WN3YyiNGIIrYzZK0tOOjZuQ13ELzBOgCMgso0zh3 wmrgkAV031HXdY/R1tsYDaVPx0g3VCBtz7UzE+qkE03S54xa2LQQ1WRGMOt5kOfTHW7R zCwIQlHh41CbTaF9K0DXx/GtsbiakntYpyh8QGXvKenHRWVrw74uEwa1JTDYM+iZuGX0 DYph1OQwd862gDMAWdHuRHDtoVwhg70jRGZoSbikxA8UFPVJ3yods9UvZI05ckiGro93 7Dv+j033zIsKvw9rgS2Rj6YycrjWJKm2OIHaAWBgZIByySw4g2HzXwfJ/KmoZgi1Vy9n dzjQ== 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: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=PEKadXCD5QWMWmrWLft2JHaTmI0a2hGNW89Pm46Xi5U=; b=KmFa/NnHjhiq8s82/dbGjg+YuJkUOOSfuQnZhsiDRt4S32NWhojSTOwTaebhVP4mPY U8m2iJe78N8ajSbrl77mD9ozXgDmsp1Z7uwzdV36Ga5Of3BjS/g0/vcGIhOaTEcr0zFw yOSAcZoC61OPW8hpZvJ3VeUKGQOnz02+SqAz3V25GKy4Ui93eFisN5pDzgugqxUijnlx NjgkAt2PMJxPJ4PBRx4bIM09jd6CNLOItZrf0oXJoHyrWkZfRKot6PzOn/EBrniUnPB1 QAC7YpbBgiR1nrzYXa8JHuH2VBrfGLuMzKURNmuQNnOXCzqqM1ZSTU81jhv8I6Quoga+ dTAQ== X-Gm-Message-State: AFeK/H1UHco0t5IV7vUGpK+VslMQayvzgOetzzDdeveIWu4L9TNV359qYGiwlAgOg84uQw== X-Received: by 10.159.56.202 with SMTP id w10mr270413uaf.31.1490801008734; Wed, 29 Mar 2017 08:23:28 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.157.14.57 with SMTP id c54ls13701390otc.48.gmail; Wed, 29 Mar 2017 08:23:27 -0700 (PDT) X-Received: by 10.157.18.133 with SMTP id g5mr196860otg.8.1490801007828; Wed, 29 Mar 2017 08:23:27 -0700 (PDT) In-Reply-To: <58DA6B66.2010307@gmail.com> X-Original-Sender: tongari95@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:31878 Archived-At: ------=_Part_1525_1771935987.1490801007373 Content-Type: multipart/alternative; boundary="----=_Part_1526_1708625297.1490801007373" ------=_Part_1526_1708625297.1490801007373 Content-Type: text/plain; charset=UTF-8 On Tuesday, March 28, 2017 at 9:55:54 PM UTC+8, Matthew Woehlke wrote: > > The decomposition case I think would be best solved by allowing empty and > nested declarations. See > > https://groups.google.com/a/isocpp.org/d/msg/std-proposals/gg3_eUhCuqo/HcippDFiBgAJ > and following posts in the thread. This would let you write: > > auto [] = get_lock(); // no name > auto [x, [], y] = get_tuple(); // middle element is unnamed > auto [x, [a, b], y] = get_tuple(); // nested decomposition > > Both solve the simple case, but both also have additional but > non-overlapping usefulness. I'm inclined to think that both are useful. > While I like the idea, but compilers probably don't. In the following example: auto [[a, b], c] = get_tuple(); "[["conflicts with the attribute syntax. -- 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/75b1126c-0292-44dc-973a-c903d31b87ec%40isocpp.org. ------=_Part_1526_1708625297.1490801007373 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
On Tuesday, March 28, 2017 at 9:55:54 PM UTC+8, Matthew Wo= ehlke wrote:
The decomposition case I think would be best solved by allowing empty and
nested declarations. See
https://groups.google.com/a/isocpp.org/d/msg= /std-proposals/gg3_eUhCuqo/HcippDFiBgAJ
and following posts in the thread. This would let you write:

=C2=A0 auto [] =3D get_lock(); // no name
=C2=A0 auto [x, [], y] =3D get_tuple(); // middle element is unnamed
=C2=A0 auto [x, [a, b], y] =3D get_tuple(); // nested decomposition

Both solve the simple case, but both also have additional but
non-overlapping usefulness. I'm inclined to think that both are use= ful.

While I like the idea, but compilers p= robably don't. In the following example:
auto [[a, b], c] =3D get_tuple();

"[["= ;conflicts with the attribute syntax.

--
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To unsubscribe from this group and stop receiving emails from it, send an e= mail to std-proposa= ls+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/75b1126c-0292-44dc-973a-c903d31b87ec= %40isocpp.org.
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