220 14517 article Path: news.gmane.org!not-for-mail From: Benjamin Lindley Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Re: Range-based if Date: Wed, 12 Nov 2014 18:47:35 -0800 (PST) Lines: 65 Approved: news@gmane.org Message-ID: References: Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_Part_820_556048964.1415846855659" X-Trace: ger.gmane.org 1415846865 25161 80.91.229.3 (13 Nov 2014 02:47:45 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Thu, 13 Nov 2014 02:47:45 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBDI7THWOWMDRBSFXSCRQKGQENQXESRY@isocpp.org Thu Nov 13 03:47:38 2014 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-qa0-f71.google.com ([209.85.216.71]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1XokRe-0007hS-H8 for gclcip-std-proposals@m.gmane.org; Thu, 13 Nov 2014 03:47:38 +0100 Original-Received: by mail-qa0-f71.google.com with SMTP id n8sf28451411qaq.10 for ; Wed, 12 Nov 2014 18:47:37 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=date:from:to:message-id:in-reply-to:references:subject:mime-version :x-original-sender:reply-to:precedence:mailing-list:list-id :list-post:list-help:list-archive:list-subscribe:list-unsubscribe :content-type; bh=GFiYstyZhjvtIAy4maPYWrA5F3gipdS65W7ZctC+nSs=; b=TSCKlw+79LS6PYlMgIgLro745MP13l7AGrD6xVhlPokwc++IJGLPVeSTXV4dIAvwKj LZY+secIh3l/qtixmMCMIdc5M2+1UGC1OWMERwqBSrCShp/MNitFjqCKiIXm/0q6rrVL Co/m+j/yolI07vzAY6DiVs5jQNE60SJzhllSUnRlrzb25/oTadiYJ6l0kFkkkrh+Zi42 R8PKTPgY4nkRS5oC9bIr+BGGJOJxCZpkingCAvwoIXKx0SKW+FIFDWnLf7IqrSb3iVGf FjFIAvdZVGN4HbiojltHdMds3uE5xPG3RFBO8EQ9tWpJwgMd7ntZPm56qexLs3SRtALw kY5A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; 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:list-post:list-help:list-archive :list-subscribe:list-unsubscribe:content-type; bh=GFiYstyZhjvtIAy4maPYWrA5F3gipdS65W7ZctC+nSs=; b=CCMKJWlbG+Yz18l5gRFvTf+fES7iv/SKW/d09lrOZbNVe20V2Wq3jSY3SuObIh4kj6 vlKFtKz2xhjx1yfUQ1Q/Zc7Go0iBfz0xo9+I2GJNDzI2AJgSFe69KzwfXJyPJ/TCK+tw gWhSi5iVRcHgpqjLbsGBv571k/Rc1JdWiILGWaeDc0URyG9bydX9lbczb2sIaLefIf13 ag+iMK3jswwMuOlHZzgNcuxYZ5h1/w6Bedh1bzt8v4AAI4CZb1+IlZM6lAyfO6wdplRV 8nzUvSf+GHd+XUQd8lZHPT60yQePUOeC57kTf1VzUZfgLu/vV7HX1hPxHS9bIQr0ppCE KaQA== X-Gm-Message-State: ALoCoQn0601NJIFyUTHv1N4CybrRRsS0VYsGXch7Dz0RNhCp1zbua4siMAxUW7cIUapNNZm+soCB X-Received: by 10.236.223.198 with SMTP id v66mr39563717yhp.21.1415846857838; Wed, 12 Nov 2014 18:47:37 -0800 (PST) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.182.142.65 with SMTP id ru1ls1160126obb.46.gmail; Wed, 12 Nov 2014 18:47:36 -0800 (PST) X-Received: by 10.182.97.4 with SMTP id dw4mr132obb.33.1415846856646; Wed, 12 Nov 2014 18:47:36 -0800 (PST) In-Reply-To: X-Original-Sender: benjameslindley@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:14517 Archived-At: ------=_Part_820_556048964.1415846855659 Content-Type: text/plain; charset=UTF-8 On Wednesday, November 12, 2014 8:31:37 PM UTC-6, Brent Friedman wrote: > > > It doesn't assume that the iterators are pointers, if that's what you > mean. > It assumes that it is possible to convert from nullptr_t to decltype(&range.begin()). > It also assumes that this value constructed from nullptr necessarily > represents an invalid value (converts to false) for that iterator type. > > Well, I'm pretty sure that Matthew wrote that in a hurry, and it should really be decltype(std::addressof(*std::begin(range)). The idea is, it is a pointer (how can it not be?). In which case, it can of course convert from nullptr_t. -- --- 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. Visit this group at http://groups.google.com/a/isocpp.org/group/std-proposals/. ------=_Part_820_556048964.1415846855659 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable


On Wednesday, November 12, 2014 8:31:37 PM UTC-6, = Brent Friedman wrote:
> It doesn't assume that the iterators are pointers, if that's what you m= ean.
It assumes that it is possible to convert from nullptr_t to decltype(&ran= ge.begin()). It also assumes that this value constructed from nullptr neces= sarily represents an invalid value (converts to false) for that iterator ty= pe.


Well, I'm pretty= sure that Matthew wrote that in a hurry, and it should really be decltype(= std::addressof(*std::begin(range)). The idea is, it is a pointer (how can i= t not be?). In which case, it can of course convert from nullptr_t.

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