220 14519 <92a159e9-a182-4d21-ba7d-405f1f4e9cdf@isocpp.org> 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 18:53:24 -0800 (PST) Lines: 93 Approved: news@gmane.org Message-ID: <92a159e9-a182-4d21-ba7d-405f1f4e9cdf@isocpp.org> References: Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_Part_930_1062945902.1415847204756" X-Trace: ger.gmane.org 1415847214 30237 80.91.229.3 (13 Nov 2014 02:53:34 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Thu, 13 Nov 2014 02:53:34 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBDI7THWOWMDRBJN2SCRQKGQEGDGOD6Y@isocpp.org Thu Nov 13 03:53:28 2014 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-oi0-f71.google.com ([209.85.218.71]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1XokXH-0001qA-0t for gclcip-std-proposals@m.gmane.org; Thu, 13 Nov 2014 03:53:27 +0100 Original-Received: by mail-oi0-f71.google.com with SMTP id i138sf2720507oig.6 for ; Wed, 12 Nov 2014 18:53:26 -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=ViEGsuIM9SzhNoECNVARiBOORBe/lbPuiaNNGjJdXcE=; b=u4uEgkQI6cE8p5c1wyQOBZZgzwt5A8JDXMFsveVD6HlI9SXMI/fj2wxpArFGtXl/vA Cod32HFsg1l+hS4UDy4FuHSYGu0gnird6WCXdvu0XQV81mgsmvxGSTsCKzfcshKON80N frx9N1uy6ud/4qI5bgPe06rt9668sOrFH6KqRO7KZr6Dch/WrlA46riQrwJroAE0kL+i Ka2THZZWAtAiyIxwT7ydEoJNsEMuUgajsoeZFXZ0Yt5j7a6Ms2UeEfO0o8z1jnXL7RAX GghG6XwjjY2r5cMQ4waMYZ5wcraWbwtfKTsNBy/MGkW9LwRUuXaDuNoSl159Woj0Qppf YbHw== 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=ViEGsuIM9SzhNoECNVARiBOORBe/lbPuiaNNGjJdXcE=; b=fiMpGQ/+nIjk5EsQU2NnecxDK2eCGxmgvUeEPvG28jmZ+k+xN/uFDoQngVX8vK6qWh c8pP7vTcwe7DKG5llo4TeAq4Yf1tTFKEbupB6XVdBTnaD3Gx163cWVj9n5E0HT3eMYZu hTyOOuclC+8YFkxsMvQT484YIYUw21oHipWeELP9FE3JNQ4uqKUf6dqvFxHbJIsfN7N4 riK/r98GpkDL+Ij9i7/il0od/k1rv+gqAniXurzvRTf6a31vXRYIjr7Q6u0SDqurn3yM pG9XApqo/If4H8NtUooVY0ik3WnUEdHETtq/2D6iymdxZYQe0ozooqswALCcBws4VSWI gGsw== X-Gm-Message-State: ALoCoQltnH9wXhEK284S8ObkyJCZYzy6SCHd7QiO9TZzAvBykYy0P+5v8gdbFbZPBaIZwtk6HDQz X-Received: by 10.42.198.140 with SMTP id eo12mr44784634icb.20.1415847206239; Wed, 12 Nov 2014 18:53:26 -0800 (PST) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.182.55.69 with SMTP id q5ls1225224obp.45.gmail; Wed, 12 Nov 2014 18:53:25 -0800 (PST) X-Received: by 10.182.94.205 with SMTP id de13mr503obb.23.1415847205279; Wed, 12 Nov 2014 18:53:25 -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:14519 Archived-At: ------=_Part_930_1062945902.1415847204756 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On Wednesday, November 12, 2014 8:31:35 PM UTC-6, David Krauss wrote: > > > On 2014=E2=80=9311=E2=80=9313, at 9:43 AM, Benjamin Lindley > wrote: > > > > On Tuesday, November 11, 2014 8:39:34 PM UTC-6, Brent Friedman wrote: >> >> > auto first_or_null(auto range) -> decltype(&range.begin()) >> >> This assumes pointers, which while addressing some use cases it isn't=20 >> sufficient for the general case. >> >> > What case does it not handle? And what exactly do you mean by "This=20 > assumes pointers"? It doesn't assume that the iterators are pointers, if= =20 > that's what you mean.=20 > > > It doesn=E2=80=99t cover smart pointers. > Smart pointers aren't ranges that have a first element, so I'm not sure why= =20 you would expect them to be covered by this. The proposal you refer to=20 solves a completely different problem, afaict. --=20 ---=20 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 e= mail 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-proposa= ls/. ------=_Part_930_1062945902.1415847204756 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable


On Wednesday, November 12, 2014 8:31:35 PM UTC-6, = David Krauss wrote:

On 2014=E2=80=9311=E2=80=9313, at 9= :43 AM, Benjamin Lindley <benjame..= ..@gmail.com> wrote:



On Tuesday, November 11, 2014 8:39:34 PM UTC-6, Brent Friedman = wrote:
> auto first_or_nul= l(auto range) -> decltype(&range.begin())

= This assumes pointers, which while addressing some use cases it isn't suffi= cient for the general case.

What case does it not handle? And what exactly do you mean by "This assume= s pointers"? It doesn't assume that the iterators are pointers, if that's w= hat you mean.

It doesn=E2= =80=99t cover smart pointers.

Smart = pointers aren't ranges that have a first element, so I'm not sure why you w= ould expect them to be covered by this. The proposal you refer to solves a = completely different problem, afaict.

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