Path: csiph.com!eternal-september.org!feeder.eternal-september.org!feeds.phibee-telecom.net!newsfeed.xs4all.nl!newsfeed8.news.xs4all.nl!nzpost1.xs4all.net!not-for-mail Return-Path: X-Original-To: python-list@python.org Delivered-To: python-list@mail.python.org X-Spam-Status: OK 0.019 X-Spam-Evidence: '*H*': 0.96; '*S*': 0.00; 'conversions': 0.07; 'matches': 0.07; 'received:internal': 0.09; 'times,': 0.13; 'message-id:@webmail.messagingengine.com': 0.16; 'opposite': 0.16; 'received:10.202': 0.16; 'received:10.202.2': 0.16; 'received:10.202.2.212': 0.16; 'received:66.111': 0.16; 'received:66.111.4': 0.16; 'received:messagingengine.com': 0.16; 'timezones': 0.16; 'unambiguous': 0.16; 'wrote:': 0.16; 'sep': 0.22; 'subject:skip:i 10': 0.22; 'sat,': 0.23; 'header:In-Reply- To:1': 0.24; "doesn't": 0.26; 'mostly': 0.27; 'correct': 0.28; "i'm": 0.30; 'implement': 0.32; 'problem': 0.33; 'definition': 0.34; 'clear': 0.35; 'possible': 0.36; 'subject:" ': 0.36; 'to:addr:python-list': 0.36; 'subject:?': 0.36; 'subject:: ': 0.37; 'received:10': 0.37; 'really': 0.37; '12,': 0.37; 'times.': 0.38; 'received:66': 0.38; 'to:addr:python.org': 0.40; 'from:no real name:2**0': 0.60; 'your': 0.60; 'header:Message-Id:1': 0.61; 'times': 0.63; 'subject:there': 0.66; 'talking': 0.67; 'meyer': 0.84; 'subject:any': 0.84; 'subject:Are': 0.95 DKIM-Signature: v=1; a=rsa-sha1; c=relaxed/relaxed; d=fastmail.us; h= content-transfer-encoding:content-type:date:from:in-reply-to :message-id:mime-version:references:subject:to:x-sasl-enc :x-sasl-enc; s=mesmtp; bh=1tKaVH5f/30csXwDkrF1MQv6Zb8=; b=UQW8yr EawArL23EPSj6gE7vuxvZZw39EUD5yE+MuzPIdtAUlan7kSZc5d/qWwjfayHFiBq qdT+EfT/DFVTfyjFZowHttnnIMnAt2sL1ongPB2TfOkJi37x6pDqOgdPeBvG5bgD WKU9bocrWTEajQRmrfIHI5aqfAcQsAAQRwOcU= DKIM-Signature: v=1; a=rsa-sha1; c=relaxed/relaxed; d= messagingengine.com; h=content-transfer-encoding:content-type :date:from:in-reply-to:message-id:mime-version:references :subject:to:x-sasl-enc:x-sasl-enc; s=smtpout; bh=1tKaVH5f/30csXw DkrF1MQv6Zb8=; b=egTJ7XL3RQw5kh9/n+PyRMM2xxA17JFpGmuUUcpRGDIgIaf AYCaFopQVu8OyNM8SPiVuHZyJ/45z4mYxPP58awa6MFjKp43tZ+Bha+S5nWZh04E QWome4DCByf0E0xOtylduKQcHYz2n1sewwsGBO+n+5DyAgaE/xGuIj3+F660= X-Sasl-Enc: ZvlCm7raDbE+9G2c0tzbcs6aDFS3T5xqigXR9CFP4QWy 1442085539 From: random832@fastmail.us To: python-list@python.org MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Type: text/plain X-Mailer: MessagingEngine.com Webmail Interface - ajax-c76b43ce Subject: Re: Are there any "correct" implementations of tzinfo? Date: Sat, 12 Sep 2015 15:18:59 -0400 In-Reply-To: <55F47098.80706@oddbird.net> References: <55F47098.80706@oddbird.net> X-BeenThere: python-list@python.org X-Mailman-Version: 2.1.20+ Precedence: list List-Id: General discussion list for the Python programming language List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Newsgroups: comp.lang.python Message-ID: Lines: 11 NNTP-Posting-Host: 2001:888:2000:d::a6 X-Trace: 1442085541 news.xs4all.nl 23756 [2001:888:2000:d::a6]:49497 X-Complaints-To: abuse@xs4all.nl Xref: csiph.com comp.lang.python:96449 On Sat, Sep 12, 2015, at 14:36, Carl Meyer wrote: > Well, the problem is that because datetime doesn't include any way to > disambiguate ambiguous times, it's not really possible to implement > complex timezones in a way that is both correct (if your definition of > correct includes "timezone conversions are lossless") and also matches > the intended model of datetime. I'm not even talking about ambiguous times. I'm mostly talking about unambiguous times on opposite sides of the transition. It's not even clear to me how the model of datetime envisions _those_ working with "classic arithmetic".