220 2328 article Path: news.gmane.org!not-for-mail From: Tony V E Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: optional, one more value or two states Date: Sun, 27 Jan 2013 00:34:59 -0500 Lines: 79 Approved: news@gmane.org Message-ID: References:

<2c2b9360-8e5e-422d-9b85-124bd947b004@isocpp.org> <4f505b21-669a-4ef0-95b9-edf9e5afa22d@isocpp.org> <36691ed8-3c44-4eb5-885f-27067fce7f40@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 X-Trace: ger.gmane.org 1359264902 3991 80.91.229.3 (27 Jan 2013 05:35:02 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Sun, 27 Jan 2013 05:35:02 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBCUZ5QWKNQIIJ6MSRACRUBBPXHCE4@isocpp.org Sun Jan 27 06:35:22 2013 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-vb0-f71.google.com ([209.85.212.71]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1TzKtj-0000ax-Hq for gclcip-std-proposals@m.gmane.org; Sun, 27 Jan 2013 06:35:19 +0100 Original-Received: by mail-vb0-f71.google.com with SMTP id p1sf2400717vbi.6 for ; Sat, 26 Jan 2013 21:35:01 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=x-received:x-beenthere:x-received:x-received:received-spf :mime-version:x-received:in-reply-to:references:date:message-id :subject:from:to:x-original-sender:x-original-authentication-results :reply-to:precedence:mailing-list:list-id:x-google-group-id :list-post:list-help:list-archive:list-subscribe:list-unsubscribe :content-type; bh=rg9s5vFPPr/sKGpfErf4Ngd6c/CIhXkSvwcvvptDF+A=; b=eMVeWIZtZW7Cnb+7j0Bp1M26BurFPxb0kTkHD0v5dkx4RzrOAfeCqggAICb0DRsOC8 gcHBkyk7/PCE396QgT12qYHbB/aVd1gcEwhudMXHy7SmXd4MudwMFVj5rVsI3uCBVQDh EIyFo+8p2S9CgGdsK87w9HP1WbcZnk9ny88gpDLCNERk1vOENNQxqKTISLzP5uYR0ata JhYxYCj1EJnYJa6jgaK0eBpuUjfXW0MDstf7hogfKhqdcTxZyldY8MDXnKOPGJ5hJRfH gDWZwwOpoGe+g5ssFTaCy5azFRzaK7WcSXER7hIO8w6XxkJac X-Received: by 10.224.60.6 with SMTP id n6mr4830489qah.8.1359264901023; Sat, 26 Jan 2013 21:35:01 -0800 (PST) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.49.30.36 with SMTP id p4ls666912qeh.74.gmail; Sat, 26 Jan 2013 21:34:59 -0800 (PST) X-Received: by 10.49.61.37 with SMTP id m5mr13447877qer.12.1359264899925; Sat, 26 Jan 2013 21:34:59 -0800 (PST) X-Received: by 10.49.61.37 with SMTP id m5mr13447875qer.12.1359264899878; Sat, 26 Jan 2013 21:34:59 -0800 (PST) Original-Received: from mail-qc0-f171.google.com (mail-qc0-f171.google.com [209.85.216.171]) by mx.google.com with ESMTPS id r17si139546qct.199.2013.01.26.21.34.59 (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Sat, 26 Jan 2013 21:34:59 -0800 (PST) Received-SPF: pass (google.com: domain of tvaneerd@gmail.com designates 209.85.216.171 as permitted sender) client-ip=209.85.216.171; Original-Received: by mail-qc0-f171.google.com with SMTP id d1so839273qca.30 for ; Sat, 26 Jan 2013 21:34:59 -0800 (PST) X-Received: by 10.49.12.138 with SMTP id y10mr13041751qeb.64.1359264899663; Sat, 26 Jan 2013 21:34:59 -0800 (PST) Original-Received: by 10.49.87.168 with HTTP; Sat, 26 Jan 2013 21:34:59 -0800 (PST) In-Reply-To: <36691ed8-3c44-4eb5-885f-27067fce7f40@isocpp.org> X-Original-Sender: tvaneerd@gmail.com X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of tvaneerd@gmail.com designates 209.85.216.171 as permitted sender) smtp.mail=tvaneerd@gmail.com; dkim=pass header.i=@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:2328 Archived-At: On Sat, Jan 26, 2013 at 5:09 AM, Vladimir Batov wrote: > On Saturday, January 26, 2013 10:22:11 AM UTC+11, Nicol Bolas wrote: >> >> On Friday, January 25, 2013 2:09:20 PM UTC-8, Tony V E wrote: >>> >>> On Fri, Jan 25, 2013 at 3:20 PM, Nicol Bolas wrote: >>> > ... >>> Do you think we should back away from all the pointer-ish interface >>> parts and move more towards container-ish? > > > "We" are reading the 3rd revision of the document describing the facility > which has been in heavy use for a while and which has already been submitted > for standardization. "we should back away from all the pointer-ish > interface"... Is it a serious question or a tease? > I'm not sure of your point, but if your point is that a lot of time and effort has already been put in (and I suspect it has!) or that we are too far along in the process: I'd much rather put the extra effort in now than have thousands of programmers deal with it post standardization. Or worse yet, have a feature that we still discuss changing _after_ standardization (ie uniform initialization as just one example. exported templates,...). > >> >> No it should not. I'm not particularly enamoured with `operator*`, but >> `operator[]` makes no sense at all. Why not just `value` (or `get` for those >> who like that)? Do we really need an operator at all? > > > Uhm, because we need to dereference 'optional' and the language has a > dereferencing operator (op*) which happens to be used everywhere else to > dereference. > >> >> There is no "all the pointer-ish interface"; there's only `operator*. >> That's the only part of optional that is like a pointer (OK, the `explicit >> operator bool` too, but that's hardly unique to pointers); everything else >> works differently from pointers. > > > There is nothing "pointer-ish" about the operator called a dereferencing > operator. Customization (oveloading) of that op* together with the other > dereferencing op->() is "important to a class of interesting programs" (as > Stroustrup puts it). Indeed, that interface (as many other concepts) has > been borrowed from C where these operators worked with pointers and C++ > intentionally preserves C syntactic flavor. It does not make pointers claim > "ownership" of these operators. These operators are the standard interface > for the whole family of classes implementing the proxy concept/pattern... > and the pointer is just one -- the most basic and primitive -- > implementation of that concept. > > > -- > > --- > 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/?hl=en. > > -- --- You received this message because you are subscribed to the Google Groups "ISO C++ Standard - Future Proposals" group. To post to this group, send email to std-proposals@isocpp.org. To unsubscribe from this group, send email to std-proposals+unsubscribe@isocpp.org. 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