220 8716 <10a34567-ba5b-4549-88e3-51ce47867352@isocpp.org> article Path: news.gmane.org!not-for-mail From: Olaf van der Spek Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: string_view::is_null() Date: Sun, 19 Jan 2014 16:11:32 -0800 (PST) Lines: 79 Approved: news@gmane.org Message-ID: <10a34567-ba5b-4549-88e3-51ce47867352@isocpp.org> References: <8E74B747-7450-41E0-8D1E-48C2D6F81535@gmail.com> <104254A6-C69A-4571-8455-89D7E466D493@gmail.com> <6a95bf9c-55c9-4ae2-966f-d1b1f4df6a37@isocpp.org> <52D9E336.1060801@knejp.de> <1B534FD7-B385-4A7E-A718-3C73F0AB61DC@gmail.com> <11f13f8f-1270-427c-8942-94027a181ff4@isocpp.org> <20140119174431.GA16875@faust.lysator.liu.se> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_Part_753_31806092.1390176692321" X-Trace: ger.gmane.org 1390176687 11209 80.91.229.3 (20 Jan 2014 00:11:27 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Mon, 20 Jan 2014 00:11:27 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBC5NB45SSABBBNGT6GLAKGQE7WUKX3A@isocpp.org Mon Jan 20 01:11:35 2014 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-yk0-f197.google.com ([209.85.160.197]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1W52Sk-00049R-Kv for gclcip-std-proposals@m.gmane.org; Mon, 20 Jan 2014 01:11:34 +0100 Original-Received: by mail-yk0-f197.google.com with SMTP id 20sf5233379yks.0 for ; Sun, 19 Jan 2014 16:11:33 -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=gLXAblZecx8Xina7rBxgvE9kjOwBfjAs9WYgsY6eeYE=; b=YxWId3BO4dEx8VcvYWRqnhOmkOO1QrKBo2PAXXCt3LDrW+WcYUpP7t4uaHQmSMeIKe kK3pffV0mZsuulsg001OoTC45R817IukiaR3ATPxAR+2YYe+SHE9Y0RnHOPltX+UeIHU PJUsS6YynD3QG3ZjOoS9TT+hFtDrNfnHDUjRQsOY+2GdvGZgfxzbLZ0ZKJrHkRd/e/sp 05xUdWe9qEYPPN2FHp2gZu3b6xnARKMxz8v5kV8Oq3pG0vJQVr13gO0RdSktGCRzfldr Gw0wtdOIm62/Fskl8E+2fryMU5bs3FxO78R6xLa5PyXgaA5U9d4JZ8Hrz0LVTI7eWbYK j8PA== 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=gLXAblZecx8Xina7rBxgvE9kjOwBfjAs9WYgsY6eeYE=; b=TLW5gqk+FOLuy9jj0BpqYT28aN1NSoVNq+NqpEuAygV8mTSAB+CaFR52S7ajixiOb6 ftlGDyPpOAmXTdcw1jwPVVQsyQ7MDX1cq9v0PYz78ebRafMyidtBk1iA8m/ghONqmZet 3ZW+l9HRclUIiWFH6D9YOLFo11VUmFlkAYIs/5D0wVaJ3B9tI5nP7gv+mT99GvpJnA83 WYdJVSzTrlq/yUleJxOcnWzTRFgZCLWMavEcpm8pIYdTEyDScHHoXJBl0w26PoEyaKSP lYMbCfaUQ980PRqhiAaBQQtWR1bCigLN8tLnY84iQ3csBTLF+GZAbt7uLtzoPo9t61Ry 7xRg== X-Gm-Message-State: ALoCoQku87jT9xIp2XTmg11VEUATHM2CbtovddDCAUN+2DWfPqoCNnlJhzIBLOheJwaaoTrCfE3a X-Received: by 10.58.156.42 with SMTP id wb10mr5583680veb.26.1390176693269; Sun, 19 Jan 2014 16:11:33 -0800 (PST) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.140.32.228 with SMTP id h91ls908156qgh.14.gmail; Sun, 19 Jan 2014 16:11:32 -0800 (PST) X-Received: by 10.140.83.212 with SMTP id j78mr398148qgd.3.1390176692731; Sun, 19 Jan 2014 16:11:32 -0800 (PST) In-Reply-To: X-Original-Sender: olafvdspek@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:8716 Archived-At: ------=_Part_753_31806092.1390176692321 Content-Type: text/plain; charset=UTF-8 Op zondag 19 januari 2014 19:31:19 UTC+1 schreef Peter Bigot: > > On further reflection it'd better to store a null pointer in m_ptr to > represent a default-constructed value but to return &m_nul from data() when > m_ptr is null. > Having such conditionals in data() doesn't seem like a good idea. data() should be as simple (and as fast) as possible. > constexpr basic_string_view(const charT* str, size_type len); *> Requires*: str is not a null pointer and [str,str + len) is a valid range. What's the rationale for the not-null requirement? I don't like it, one should be able to construct a string_view from a NULL, 0 pair. vector::data() could return NULL (AFAIK), so that'd mean I couldn't construct a string_view from v.data(), v.size() -- --- 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_753_31806092.1390176692321 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
Op zondag 19 januari 2014 19:31:19 UTC+1 schreef Peter Big= ot:
On further reflection it'd better to store a nul= l pointer in m_ptr to represent a default-constructed value but to return &= amp;m_nul from data() when m_ptr is null.  

Having such conditionals in data() doesn't se= em like a good idea. data() should be as simple (and as fast) as possible.<= /div>

> constexpr basic_string_view(const charT* str, size_type = len);
> Requires: str is= not a null pointer and [str,str + le= n) is a valid range. 

<= div>What's the rationale for the not-null requirement? I don't like it, one= should be able to construct a string_view from a NULL, 0 pair.
v= ector::data() could return NULL (AFAIK), so that'd mean I couldn't construc= t a string_view from v.data(), v.size()

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