220 9097 article Path: news.gmane.org!not-for-mail From: Olaf van der Spek Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Re: String to T conversions - getting it right this time Date: Wed, 5 Feb 2014 15:08:04 +0100 Lines: 57 Approved: news@gmane.org Message-ID: References: <097fb6c8-56f9-433e-a2f0-8c0f69609bf0@isocpp.org> <5061438.KRSokrkgRP@tjmaciei-mobl4> <866adea3-6322-4c6a-96f8-ea76a5d7ea7c@isocpp.org> <03d172fa-2886-4d24-8943-ad6481b330b2@isocpp.org> <58810bd8-32aa-471d-bf2c-1d5580d48c31@isocpp.org> <48d8fd32-568d-4f06-86c5-e7ab64f19632@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-Trace: ger.gmane.org 1391609282 5685 80.91.229.3 (5 Feb 2014 14:08:02 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Wed, 5 Feb 2014 14:08:02 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBC5NB45SSABBBRMLZGLQKGQENISWXFQ@isocpp.org Wed Feb 05 15:08:09 2014 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-yk0-f199.google.com ([209.85.160.199]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1WB395-0002sJ-4n for gclcip-std-proposals@m.gmane.org; Wed, 05 Feb 2014 15:08:07 +0100 Original-Received: by mail-yk0-f199.google.com with SMTP id 142sf1944935ykq.2 for ; Wed, 05 Feb 2014 06:08:06 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:in-reply-to:references:date :message-id:subject:from:to:x-original-sender :x-original-authentication-results:reply-to:precedence:mailing-list :list-id:list-post:list-help:list-archive:list-subscribe :list-unsubscribe:content-type; bh=Y/uf5UBYmn/WoJgefA/IBKdr/SIYQ2TvnJk5J6adjxE=; b=f+8z3zi3FxsgPd513kiJm6hM6oOb1LaFz4JlCb/j/gNCBoSq3Vr4FGfI2kGlRIhqJF pMiwMjTU8T13aK5ZYmF07KbbO4/SmbrurNbPZaSp0w4O4bh4iYRA0Hxrb0bwdJVaHQWy VYb+Ey8CQ2eGONZ9GWhSvaDdvBHB++dJjG+YuWTBLt6Un1tHTDcEhQA59gzgJYNdD3qO /qE2EBSRXgYjk0+KUIi/4MG4hCnLMGWertLi/WpWC7JARu28YyhHDBdByezX5fbx7LHR U2d9NobgCkV6dUwUPHb7ZOL0KlkjJJonndcwFuds/ogGFTsmziYHJ/b+p6/C/h0QEJTY uPDg== X-Gm-Message-State: ALoCoQm8gCENqlz2eIurFmIjjPm/5yoz96JblM//7vWebrvkwU9CnDhNhe1PJSNIKWmjamTMUnsd X-Received: by 10.58.4.166 with SMTP id l6mr4576941vel.3.1391609286231; Wed, 05 Feb 2014 06:08:06 -0800 (PST) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.140.94.41 with SMTP id f38ls122811qge.55.gmail; Wed, 05 Feb 2014 06:08:05 -0800 (PST) X-Received: by 10.224.74.129 with SMTP id u1mr1940820qaj.49.1391609285393; Wed, 05 Feb 2014 06:08:05 -0800 (PST) Original-Received: from mail-qa0-x229.google.com (mail-qa0-x229.google.com [2607:f8b0:400d:c00::229]) by mx.google.com with ESMTPS id p10si7022536qag.118.2014.02.05.06.08.05 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Wed, 05 Feb 2014 06:08:05 -0800 (PST) Received-SPF: pass (google.com: domain of olafvdspek@gmail.com designates 2607:f8b0:400d:c00::229 as permitted sender) client-ip=2607:f8b0:400d:c00::229; Original-Received: by mail-qa0-f41.google.com with SMTP id w8so573108qac.14 for ; Wed, 05 Feb 2014 06:08:05 -0800 (PST) X-Received: by 10.224.74.129 with SMTP id u1mr1940777qaj.49.1391609285084; Wed, 05 Feb 2014 06:08:05 -0800 (PST) Original-Received: by 10.229.138.6 with HTTP; Wed, 5 Feb 2014 06:08:04 -0800 (PST) In-Reply-To: <48d8fd32-568d-4f06-86c5-e7ab64f19632@isocpp.org> X-Original-Sender: olafvdspek@gmail.com X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of olafvdspek@gmail.com designates 2607:f8b0:400d:c00::229 as permitted sender) smtp.mail=olafvdspek@gmail.com; dkim=pass header.i=@gmail.com; dmarc=pass (p=NONE dis=NONE) header.from=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:9097 Archived-At: On Wed, Feb 5, 2014 at 7:02 AM, Matthew Fioravante wrote: > After reading Matthew's posts (the other matthew, not me!). I like his ideas > better. The below is very elegant. > > auto result = parse("1234"); > if(!result) { > //handle error > //Can do switch(result.error()) if we want > } > use(result.value()); int result; if (auto err = parse(result, "1234")) { //handle error //Can do switch(err) if we want } use(result); ;) > We could make value() throw on error like std::expected, giving us a C style > return code interface and C++ style exception interface all in one. If the > user explicitly checks the error status before calling value(), its easy for > the compiler to optimize out the conditional and the throwing logic Are you sure it's easy? Got a reference? > What radix do I use? Have a base/radix parameter defaulting to 10. > Do I allow 0x and 0 (octal) prefixes? I'd allow 0x (when radix = 0), I'd never allow 0. > Do I allow + prefix? Sure, why not? > Locales? > Commas or just digits? Both handled by a locale-aware variant. > First, I think we would need to decide on a complete set of options. The > next big question is what is the best interface which will allow the user to > specify them easily and what are the most sensible defaults? -- --- 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/. .