220 28432 article Path: news.gmane.org!.POSTED!not-for-mail From: Matthew Woehlke Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Something is better then nothing: Please, relax Initializer List use with operators! Date: Thu, 22 Sep 2016 12:21:42 -0400 Lines: 45 Approved: news@gmane.org Message-ID: References: <0892f743-bca2-4f18-b023-d4a57cea60fb@isocpp.org> <0e27bc76-eada-4d70-80d7-b91b5a2d5767@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 1475070203 1890 195.159.176.226 (28 Sep 2016 13:43:23 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Wed, 28 Sep 2016 13:43:23 +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+bncBC37LBFWUIFBBZMRV67QKGQERRPJGGA@isocpp.org Wed Sep 28 15:43:17 2016 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-qt0-f200.google.com ([209.85.216.200]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1bpF8W-0006FL-Et for gclcip-std-proposals@m.gmane.org; Wed, 28 Sep 2016 15:43:00 +0200 Original-Received: by mail-qt0-f200.google.com with SMTP id 16sf55499004qtn.1 for ; Wed, 28 Sep 2016 06:43:02 -0700 (PDT) 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: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=gWhwLPBYcBGTM4E6lUJit18QFbPalWJQjWNAEi9bUsE=; b=Btgk8BHfXOrNE9ixFrWe+BPlNFqs7bDvTgqFjXcNLZBTibBH3cfqFnSa2Hv6GJq4fi wfn2yeQzeozsSerFtuA+BjCNFIPkWCyGyI/LzUTmZSP72GV14QQr3jbtpcK1UutFJbAh CtBJ2Ozux7abkzBLoSurRnWxolAzVGFO2GQ2zhuVWn1WUiupVmwBFQizLITJvXIk5s0m BPATr22nKGcBucLth9NXuf4KHG93kwmvRWry4iNVrpJ3zhP3aQvd7TKH4ekiMnCBfXyv bbXOgKm3Bq9y2/k33Yksv+dG3OsgmVq+B5ybjwZZfKnMxtpC/pSVnyA2oHAsN89nY8tm trmA== 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:user-agent:in-reply-to: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=gWhwLPBYcBGTM4E6lUJit18QFbPalWJQjWNAEi9bUsE=; b=Tues/ITZ6QenWOYZDW66f0qIGjfXjBBdLEoHj+nK8FgBLzdJVMD6vzbS3999PSJWG+ V868mpChzj5DFWjDD+H3GzaviwK/DLTt+NmdWfparFpRZSjlVFGjqdu5FyQ+ivIdAtRZ P7N0nP2czJfxAwyRi6rRHxdfaLWEGskHOGkf1hc++Jeclc3lNOnOGppe3dabskfGHcsF eMiOuPCnKT7S2r9lw+yfgu4r9bXG5078OY2e+zMBRkwUo8hyp2KTfc2J5dupRvOecOyb MO8KivJ5qLTevsPL8iarTrRIOoZs2xh07+g0Uisn+RGvqsqwopqquosrxpIG7+GnWcMr Oywg== X-Gm-Message-State: AA6/9RnQWCuZTj9f6QjsEJbwpmpouoFUohmrg/nfNw6qBPSy4FvWzAVhOIgp1VrEBXd+pg== X-Received: by 10.200.35.252 with SMTP id r57mr8331678qtr.30.1475070182032; Wed, 28 Sep 2016 06:43:02 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.157.20.68 with SMTP id h62ls923484oth.17.gmail; Wed, 28 Sep 2016 06:43:01 -0700 (PDT) X-Received: by 10.13.255.67 with SMTP id p64mr8941844ywf.137.1475070181094; Wed, 28 Sep 2016 06:43:01 -0700 (PDT) Original-Received: by 10.55.9.211 with SMTP id 202msqkj; Thu, 22 Sep 2016 09:22:03 -0700 (PDT) X-Received: by 10.25.15.38 with SMTP id e38mr1122727lfi.24.1474561322714; Thu, 22 Sep 2016 09:22:02 -0700 (PDT) Original-Received: from blaine.gmane.org ([195.159.176.226]) by mx.google.com with ESMTPS id k82si1338589lfd.92.2016.09.22.09.22.02 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 22 Sep 2016 09:22:02 -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 1bn6ky-0005S4-Va for std-proposals@isocpp.org; Thu, 22 Sep 2016 18:21:52 +0200 X-Injected-Via-Gmane: http://gmane.org/ Original-Lines: 38 Original-X-Complaints-To: usenet@blaine.gmane.org X-Enigmail-Draft-Status: N1110 In-Reply-To: X-Original-Sender: mwoehlke.floss@gmail.com 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; 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-Google-Group-Id: 399137483710 List-Post: , List-Help: , List-Archive: List-Subscribe: , List-Unsubscribe: , Xref: news.gmane.org gmane.comp.lang.c++.isocpp.proposals:28432 Archived-At: On 2016-09-21 12:57, mihailnajdenov@gmail.com wrote: > It should be noted the {,} statement is not an std::initializer_list all by > itself (IIRC). It can be converted to such like in the auto list = {,}; > Also beginning a statement with { is already a new scope. If that was the only problem, it's easily solved (again, let `@` be some operator): auto{...} @ foo ....and of course it doesn't come up if the expression is in an `if()`, or the RHS of an assignment (e.g. `auto x = {...} @ y`). So I don't think this should kill using an initializer-list as an operand of an expression like `x @ y`. What *does* kill it (on the LHS) is that the left operand of `x @ y` is what determines where `operator@` is looked up, and (at least presently) std::initializer_list has no operators. WHICH IS FINE! > *But the fact it can't be used on the LHS should not forbid using it on the > RHS* - they are already rhs-only (were used in such context), AND are > mostly needed there anyway! Exactly. I disagree with the assertion that we can't allow it on the RHS because we can't allow it on the LHS. There is a perfectly valid and consistent reason why it makes no sense on the LHS (see above), that is true for *any* left operand, not just std::initializer_list. Extrapolating from that that we should not allow it on the RHS either does not follow. > The perfect should not be the enemy of the good. Agreed! -- 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/ns10ek%247ip%241%40blaine.gmane.org. .