220 31898 <58DD162C.30902@gmail.com> article Path: news.gmane.org!.POSTED!not-for-mail From: Matthew Woehlke Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: This variable should not be named: an identifier (not) to remember Date: Thu, 30 Mar 2017 10:29:00 -0400 Lines: 50 Approved: news@gmane.org Message-ID: <58DD162C.30902@gmail.com> References: <985b9b2a-c734-45eb-95f4-db4dc0d309a1@isocpp.org> <00f80877-4564-406b-9dc5-d2d961b8dce3@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-Trace: blaine.gmane.org 1490884146 14055 195.159.176.226 (30 Mar 2017 14:29:06 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Thu, 30 Mar 2017 14:29:06 +0000 (UTC) User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.1.0 To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBC37LBFWUIFBBLVM6TDAKGQEX6BHAGA@isocpp.org Thu Mar 30 16:29:02 2017 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-vk0-f71.google.com ([209.85.213.71]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1ctb4L-0002nP-Re for gclcip-std-proposals@m.gmane.org; Thu, 30 Mar 2017 16:28:58 +0200 Original-Received: by mail-vk0-f71.google.com with SMTP id l65sf21285102vkd.11 for ; Thu, 30 Mar 2017 07:29:04 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=isocpp-org.20150623.gappssmtp.com; s=20150623; h=subject:to:references:newsgroups:from:message-id:date:user-agent :mime-version: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=p894opC82nw7dWNWT24LOJF0QV4DaerE0zu7PcL4iCY=; b=FhihtLGlkZbWWE7Xp35z12vZmCLLac/BrXta31sOZfLfHeHXTByDUNI5Is/DvOi6Xk WWdVhtwhHhpn28lTo8jigk8KbyoTMFUgvHfF8HDle9xBleo1FgTD+JE/YP/F8KSeKUb6 3nyVCL+9kQk19ytI+mtKoAv17QJnicmJTXyTuWSesIW8gNjypnN4YV6qbxVTuVtnpiKN 8VbN/jNTAoogwz6Vv+/yk0qBi+BRdu7QV5nr/hn1h1mLj2oQw1IJdBZWzDIsJgEZKXWl RG3Um8JeBQeWBCXDcVW7lZ6k4/Dn3vlK7Lrd3jNl/dZ7kAch+/hw7UGeO7E3fEO19VVM os7w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:references:newsgroups:from:message-id :date:user-agent:mime-version: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=p894opC82nw7dWNWT24LOJF0QV4DaerE0zu7PcL4iCY=; b=LczVwdFqDoeLIJz1hEb57e1ff7rqHEQhtP3ggoOCWs1TSN2TGeL/nWqTfJjkCii6n6 jr+DpSt5ZW0+jtzZfftTT5O2IrysHrETpXlFfqErtQH5KAEBlHryISRDelZAIxxi5XKX rwKmdkswkqdX/MLfJsDFHHqWKnS5HkXGjqR2GSqrJT5ZYMzhLrUXvuDLWi+TDlhSoKwr 77CEOwY9gsg4Sl+EJQHtGK1hp/oGeAptdGWoRDL+zdOGkTIfk99RqL9VhQjrUGz/g4mD 0pnq/L7zNimEc5wshR9puh5ulqxf844P4xT6/fx70rxJKj7dOn4RjprXCDoI8z1OnWt0 IiQQ== X-Gm-Message-State: AFeK/H0vL6OGI6gGPBRNhDeKs8ZGuWnrCvmxOoy4xzCMe3SLit22YZnx2UR8Wy0Tk7hRGQ== X-Received: by 10.31.242.137 with SMTP id q131mr1829vkh.38.1490884143722; Thu, 30 Mar 2017 07:29:03 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.107.50.212 with SMTP id y203ls6485560ioy.7.gmail; Thu, 30 Mar 2017 07:29:02 -0700 (PDT) X-Received: by 10.36.22.85 with SMTP id a82mr4508715ita.83.1490884142390; Thu, 30 Mar 2017 07:29:02 -0700 (PDT) Original-Received: from mail-it0-x22c.google.com (mail-it0-x22c.google.com. [2607:f8b0:4001:c0b::22c]) by mx.google.com with ESMTPS id y7si1334486itc.63.2017.03.30.07.29.02 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 30 Mar 2017 07:29:02 -0700 (PDT) Received-SPF: pass (google.com: domain of mwoehlke.floss@gmail.com designates 2607:f8b0:4001:c0b::22c as permitted sender) client-ip=2607:f8b0:4001:c0b::22c; Original-Received: by mail-it0-x22c.google.com with SMTP id e75so113557572itd.1 for ; Thu, 30 Mar 2017 07:29:02 -0700 (PDT) X-Received: by 10.36.92.84 with SMTP id q81mr4766197itb.46.1490884142084; Thu, 30 Mar 2017 07:29:02 -0700 (PDT) Original-Received: from [192.168.1.176] (tripoint.kitware.com. [66.194.253.20]) by smtp.googlemail.com with ESMTPSA id c91sm1420010iod.18.2017.03.30.07.29.01 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 30 Mar 2017 07:29:01 -0700 (PDT) Original-Newsgroups: gmane.comp.lang.c++.isocpp.proposals In-Reply-To: <00f80877-4564-406b-9dc5-d2d961b8dce3@isocpp.org> X-Original-Sender: mwoehlke.floss@gmail.com X-Original-Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com; spf=pass (google.com: domain of mwoehlke.floss@gmail.com designates 2607:f8b0:4001:c0b::22c as permitted sender) smtp.mailfrom=mwoehlke.floss@gmail.com; dmarc=pass (p=NONE sp=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-Google-Group-Id: 399137483710 List-Post: , List-Help: , List-Archive: List-Subscribe: , List-Unsubscribe: , Xref: news.gmane.org gmane.comp.lang.c++.isocpp.proposals:31898 Archived-At: On 2017-03-30 04:12, Raffaele Rossi wrote: > Wouldn't it be much better to have a concept of Context? I am taking > inspiration from python (I know they use it for RAII, but that is a > different discussion). > > The code might look like: > > void foo() { > // do stuff > with (unique_lock{mutex}) { > // critical code > } > // other stuff > } Or, without needing to introduce a new keyword: void foo() { // do stuff using (unique_lock{mutex}) { // critical code } // other stuff } We could support both: using (expression) { ... } using (declaration = expression) { ... } ....though of course the latter is equivalent to: if (declaration = expression; true) ....or, y'know, just using some bare {}'s, which is probably why no one has been enthusiastic about such a proposal. That may also be why this direction has not been pursued more enthusiastically; anonymous variables and/or lifetime extension just seem like a better solution... (I'm confident this has come up before...) -- 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. To view this discussion on the web visit https://groups.google.com/a/isocpp.org/d/msgid/std-proposals/58DD162C.30902%40gmail.com. .