220 8607 <2875722.TjfBuHt6Pp@tjmaciei-mobl2> article Path: news.gmane.org!not-for-mail From: Thiago Macieira Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: string_view::is_null() Date: Wed, 15 Jan 2014 09:22:22 -0800 Lines: 45 Approved: news@gmane.org Message-ID: <2875722.TjfBuHt6Pp@tjmaciei-mobl2> References: <8045a4d2-721d-4725-8bb7-7a91b6f53ec8@isocpp.org> <1140684e-4619-4b14-9e0e-fdb30d830333@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: multipart/signed; boundary="nextPart1962733.DYyL6i9T4G"; micalg="pgp-sha1"; protocol="application/pgp-signature" X-Trace: ger.gmane.org 1389806554 22590 80.91.229.3 (15 Jan 2014 17:22:34 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Wed, 15 Jan 2014 17:22:34 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBCB4TK757YBRBX4H3OLAKGQEUWAG7JQ@isocpp.org Wed Jan 15 18:22:42 2014 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-wi0-f198.google.com ([209.85.212.198]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1W3UAq-0003WS-Ed for gclcip-std-proposals@m.gmane.org; Wed, 15 Jan 2014 18:22:40 +0100 Original-Received: by mail-wi0-f198.google.com with SMTP id cc10sf3620223wib.5 for ; Wed, 15 Jan 2014 09:22:40 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:subject:date:message-id:user-agent :in-reply-to:references:mime-version:content-type: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=aVuGSrW47y62vCZsrkyzhhftl1Au98+0dJFA5KhWxGA=; b=OkOBv4p0RiqbPVDAjsKkW2Yp+6jOuHG6xxhlWphy1SFIaVKTXKdTWajtAxczH+j52A i+vuGnen/CHFB3HeJSwQIefmLpgnorOfzMEatEbgXPaTWpSsGJY3ZFyk/aUMpJKKLYqa VBFCjgBwRvIDSCQRCQbMChnq4BISdcT7YTFJvlItcX9xM9OeVjpQGPlk4R6pyde+BQjI 9rA+2sLXqlILVwE75WHfB9qtrgZ7RYAFnT8IAFTX//68PpgMvWREfX9u2Z+V49C/mwmA kAmosJ1/vD4Uk/eFjxAY//FsMLtpniTNN2neam92S4EOdAlNEmANu3/TZQrlZGdLs2nQ GCIQ== X-Gm-Message-State: ALoCoQm4AKMjMivZnm22wq1tgcyWLgZVhH5XKEZorNtD044UyZhWcx/B/rWYA6AjFv6V9Wjg5/Uq X-Received: by 10.180.108.102 with SMTP id hj6mr1561953wib.7.1389806559948; Wed, 15 Jan 2014 09:22:39 -0800 (PST) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.180.12.111 with SMTP id x15ls895625wib.5.canary; Wed, 15 Jan 2014 09:22:38 -0800 (PST) X-Received: by 10.181.13.11 with SMTP id eu11mr3538779wid.30.1389806558950; Wed, 15 Jan 2014 09:22:38 -0800 (PST) Original-Received: from gondolin.macieira.info (gondolin.macieira.info. [2a01:4f8:d13:f81:21c:14ff:fe01:12a3]) by mx.google.com with ESMTP id r1si3629878wjy.130.2014.01.15.09.22.37 for ; Wed, 15 Jan 2014 09:22:37 -0800 (PST) Received-SPF: pass (google.com: domain of thiago@macieira.org designates 2a01:4f8:d13:f81:21c:14ff:fe01:12a3 as permitted sender) client-ip=2a01:4f8:d13:f81:21c:14ff:fe01:12a3; Original-Received: from tjmaciei-mobl2.localnet (unknown [IPv6:2a01:4f8:d13:f81:21c:14ff:fe01:12a3]) by gondolin.macieira.info (Postfix) with ESMTPSA id AB7AB11B79D for ; Wed, 15 Jan 2014 09:22:36 -0800 (PST) User-Agent: KMail/4.12 pre (Linux/3.9.10-100+i915fix.fc17.x86_64; KDE/4.11.60; x86_64; git-8054221; 2013-08-01) In-Reply-To: <1140684e-4619-4b14-9e0e-fdb30d830333@isocpp.org> X-Original-Sender: thiago@macieira.org X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of thiago@macieira.org designates 2a01:4f8:d13:f81:21c:14ff:fe01:12a3 as permitted sender) smtp.mail=thiago@macieira.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:8607 Archived-At: --nextPart1962733.DYyL6i9T4G Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" On quarta-feira, 15 de janeiro de 2014 04:20:11, Olaf van der Spek wrote: > In some cases being able to distinguish between null and empty is required. > string_view could easily support this distinction, what's the reason it > should be discouraged? Just FYI Once std::string_view came into focus, I looked into QStringRef to see if it could be updated for Qt 6 and support the same semantics. Whereas std::string_view consists of two iterators (begin and end), QStringRef actually contains a pointer to the original QString, plus an offset and length. That's what I tried to change. There were two reasons why that did work: one was specifically the isNull() method, since the "nullness" is a property of the QString which a pair of iterators cannot represent. That is, a null QString and an empty-but-null QString can have the same data pointer. -- Thiago Macieira - thiago (AT) macieira.info - thiago (AT) kde.org Software Architect - Intel Open Source Technology Center PGP/GPG: 0x6EF45358; fingerprint: E067 918B B660 DBD1 105C 966C 33F5 F005 6EF4 5358 --nextPart1962733.DYyL6i9T4G Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part. 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