From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: <emacs-orgmode-bounces+larch=yhetil.org@gnu.org> Received: from mp10.migadu.com ([2001:41d0:2:bcc0::]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) by ms5.migadu.com with LMTPS id 4KXLCCNDwmMWFgAAbAwnHQ (envelope-from <emacs-orgmode-bounces+larch=yhetil.org@gnu.org>) for <larch@yhetil.org>; Sat, 14 Jan 2023 06:52:35 +0100 Received: from aspmx1.migadu.com ([2001:41d0:2:bcc0::]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) by mp10.migadu.com with LMTPS id mAntByNDwmOCEwAAG6o9tA (envelope-from <emacs-orgmode-bounces+larch=yhetil.org@gnu.org>) for <larch@yhetil.org>; Sat, 14 Jan 2023 06:52:35 +0100 Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by aspmx1.migadu.com (Postfix) with ESMTPS id B3CFAEC38 for <larch@yhetil.org>; Sat, 14 Jan 2023 06:52:34 +0100 (CET) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from <emacs-orgmode-bounces@gnu.org>) id 1pGZSJ-00088y-IV; Sat, 14 Jan 2023 00:51:52 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from <tgbugs@gmail.com>) id 1pGZSE-00087t-GL for emacs-orgmode@gnu.org; Sat, 14 Jan 2023 00:51:46 -0500 Received: from mail-yw1-x112c.google.com ([2607:f8b0:4864:20::112c]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from <tgbugs@gmail.com>) id 1pGZSC-0007xy-FX for emacs-orgmode@gnu.org; Sat, 14 Jan 2023 00:51:45 -0500 Received: by mail-yw1-x112c.google.com with SMTP id 00721157ae682-4d4303c9de6so162028937b3.2 for <emacs-orgmode@gnu.org>; Fri, 13 Jan 2023 21:51:43 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=to:subject:message-id:date:from:in-reply-to:references:mime-version :from:to:cc:subject:date:message-id:reply-to; bh=179ZuMYI5fWd7cXlz9eepXI2U99uAde624IqO5CLoZI=; b=q21DeF5X0kKpgaXMDm5Gh6g5e/YIGLIRtHiKMcU3TxRMxhpnh40cYNYnHgfn2LZlzP DlKf42/iLPXf8i7H4aa8J9bt0qa9HjUbXBVOwrJMa2Kji6mTtzq5fa+S58A9MlV9nYHh +grjoJZ8pm/WNZDGAyiqXHrS5CjkYOpB84Jund4mXTgQCTWzBOtOEIFjwLrJDc6MNMQ+ u1UvtvEPt1tIE/zeb8VAM/WO9NtI5xuKMKKIA1nJwHQC3NnLwulHYgVXS1xjIxaQ//BO dWgEdboAs2oKQtKYHUnxIRXBqeBxwHIj/ZpHX/buF8QkucLGBtuKebyJaWBbQLS9HbeH E3CA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=to:subject:message-id:date:from:in-reply-to:references:mime-version :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=179ZuMYI5fWd7cXlz9eepXI2U99uAde624IqO5CLoZI=; b=BUIzxBIvGIEZBwjxh6IXdGIIQoAxY6k4dewyNIGdaqoi5kDPiVMsfO9aFosxGeVdar VTAUgwXT+BfuDB/jX5XR2kaJJKxXVTEcNg4o52Dxyk9pQRgL5qlJYUKdxO1OYYtSI7mu NrdafMzbrOl6x6yRj8S++kpwtEuYnVluUJ6cJCDS/y1GmDS/F55g11deu1yj+u7hnbU4 vES1qn48Jr1jmTVy0OOxqnuVXecEePTgBIFRC/IcqRtDDhTou99cE2x1cdVEgJAg6Cvf 3WftJfVIAAWEX0gvLFU5v/2TCL0azkOn2/+jcP/xnY9xW2kALr7NurSD3jYKgt6S1sIF bzwA== X-Gm-Message-State: AFqh2kr4vOZ/H+HShUEWvqtNWh5SkNA/zPmTZqCqHCK4xd8LwutizkvL +ZXoVpV4HkKGb1zpVEU87TYAH3eO3hNnYz3Cq/pVG/T6SmA= X-Google-Smtp-Source: AMrXdXtVs1CO23i73cKQRgMPIgPz4QQXk3MKwRq340SisCkii8+ilkcamM5vyEI8diNFcx9ExAo/Xo9qb8UHgf2nxao= X-Received: by 2002:a0d:cc51:0:b0:4dc:8fc4:2ac0 with SMTP id o78-20020a0dcc51000000b004dc8fc42ac0mr834598ywd.117.1673675502592; Fri, 13 Jan 2023 21:51:42 -0800 (PST) MIME-Version: 1.0 References: <CAL9aZkusXaNVCu7+nO-ic8SHhwVdOiXYtDyF=Gz7h+NoLaOZXQ@mail.gmail.com> <CAJcAo8uF3m=oBOW1WVK8b9KNHgoEaND0_rcC1SAuTexx+XOSog@mail.gmail.com> In-Reply-To: <CAJcAo8uF3m=oBOW1WVK8b9KNHgoEaND0_rcC1SAuTexx+XOSog@mail.gmail.com> From: Tom Gillespie <tgbugs@gmail.com> Date: Sat, 14 Jan 2023 00:51:31 -0500 Message-ID: <CA+G3_PPcwS21HrGt9nYNJZ2+z7L_wLP5v_qcR0cCcjQ+BA5t0w@mail.gmail.com> Subject: Re: [FEATURE REQUEST] Timezone support in org-mode datestamps and org-agenda To: Org-mode <emacs-orgmode@gnu.org> Content-Type: text/plain; charset="UTF-8" Received-SPF: pass client-ip=2607:f8b0:4864:20::112c; envelope-from=tgbugs@gmail.com; helo=mail-yw1-x112c.google.com X-Spam_score_int: 0 X-Spam_score: -0.1 X-Spam_bar: / X-Spam_report: (-0.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, FREEMAIL_FROM=0.001, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, URI_DOTEDU=1.999 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: emacs-orgmode@gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: "General discussions about Org-mode." <emacs-orgmode.gnu.org> List-Unsubscribe: <https://lists.gnu.org/mailman/options/emacs-orgmode>, <mailto:emacs-orgmode-request@gnu.org?subject=unsubscribe> List-Archive: <https://lists.gnu.org/archive/html/emacs-orgmode> List-Post: <mailto:emacs-orgmode@gnu.org> List-Help: <mailto:emacs-orgmode-request@gnu.org?subject=help> List-Subscribe: <https://lists.gnu.org/mailman/listinfo/emacs-orgmode>, <mailto:emacs-orgmode-request@gnu.org?subject=subscribe> Errors-To: emacs-orgmode-bounces+larch=yhetil.org@gnu.org Sender: emacs-orgmode-bounces+larch=yhetil.org@gnu.org X-Migadu-Country: US X-Migadu-Flow: FLOW_IN ARC-Authentication-Results: i=1; aspmx1.migadu.com; dkim=pass header.d=gmail.com header.s=20210112 header.b=q21DeF5X; spf=pass (aspmx1.migadu.com: domain of "emacs-orgmode-bounces+larch=yhetil.org@gnu.org" designates 209.51.188.17 as permitted sender) smtp.mailfrom="emacs-orgmode-bounces+larch=yhetil.org@gnu.org"; dmarc=pass (policy=none) header.from=gmail.com ARC-Seal: i=1; s=key1; d=yhetil.org; t=1673675554; a=rsa-sha256; cv=none; b=dcgKK9MKfKYNq09TdiZKn2Shzf9kpRiwhuoXQk2NOMbfYktKWe221SkcAnFTcDFv7UGBpa gg75XDDRh7FUTfhRleEt8xwTIYXlaN3TjlY2UzwmNLW0UhkoaG0LtLGQTgkk4n4GvrwsX8 UkyoAo3n0ovVnY0TyovKdl+o5mrW6djMlZB8MTgAk19zLSXbEnkcy1rtRILh3eBu4DAoUy D+eIdoITHZFIw25vggm+zmrROsH6XjAyo4f/W/M3kw6TNEoeQ/I7m50tS/nnz1uVbM/ZfW LQonmSta0HORDAPyVFDqS6I9wV3BROHgwlCPyABRuASdoK5bMEb86/LacmBmCA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=yhetil.org; s=key1; t=1673675554; h=from:from:sender:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:mime-version:mime-version: content-type:content-type:in-reply-to:in-reply-to: references:references:list-id:list-help:list-unsubscribe: list-subscribe:list-post:dkim-signature; bh=179ZuMYI5fWd7cXlz9eepXI2U99uAde624IqO5CLoZI=; b=ogv8c2p4gzM6tOOzq8A8uhwkj/Cls80wKzUAhkU0VPulDRTo83xSRMt9Rzca6X1IIk9fNS VEq5c7vQCXPcTZGLbLlUohUvyb1d76ZGSVcMjlkC279ptFK1aToutc86/k8rOHJa/LbiuS r1lPMYR3M4q3DkbEntoWAQsW6C+66h9xXZacng7/goMNTz37VwB7Zcb4HsnBsSqLoYv/zq Z7hB+9GrQdjlKJPnXe8dJ+UfK1gUnwr5MVDKOiceBLVxu4z/5IkaNtMzvSb8Yt+EUtc9k/ Wodo+L1kmQvcHipJaXw9XCafdlBSSiTWjH2RdiOc6BPyJi3m4+2YUEW3yRY+zw== X-Migadu-Queue-Id: B3CFAEC38 X-Migadu-Scanner: scn0.migadu.com Authentication-Results: aspmx1.migadu.com; dkim=pass header.d=gmail.com header.s=20210112 header.b=q21DeF5X; spf=pass (aspmx1.migadu.com: domain of "emacs-orgmode-bounces+larch=yhetil.org@gnu.org" designates 209.51.188.17 as permitted sender) smtp.mailfrom="emacs-orgmode-bounces+larch=yhetil.org@gnu.org"; dmarc=pass (policy=none) header.from=gmail.com X-Migadu-Spam-Score: -7.85 X-Spam-Score: -7.85 X-TUID: m6Lo3QEFEhYh Without wading too far into this at the moment, timezones are an extremely tricky problem with a whole bunch of design considerations. I am reproducing the heading comment from laundry's timestamp.rkt in its entirety here. Best! Tom https://github.com/tgbugs/laundry/blob/master/laundry/grammar/timestamp.rkt ; the org spec is currently silent on how org will handle dates beyond ; 0000 and 9999, the relevant standards for expanded representations ; are ISO 8601-1:2019,5.2.2.3 and ISO 8601-2:2019,8.4.3. The problem ; with expanded representations is that they require all parties to ; agree ahead of time how wide the year is and prefix with + and ; leading zeros, I am not sure that this is as robust as we would like ; 0000-01-01 is january first of the year zero, -0001-01-01 is jan ; first of the year 1BCE, and +10000-01-01 for jan 1 of 10000CE 5 ; digits must be prefixed by the plus sign, the standard is not ; entirely clear, but I think that we could do PLUS digits HYPHEN ; or DIGIT-4 HYPHEN and everything would work out ; on a separate but related note, org timestamps are always in local ; time and do not currently support timezones, which is a problem ; further absurdities that are related to the timezone issue: the ; date/time implementation as a text format completely fails if ; authoring on another planet ; given my objective to ensure that org documents can be interpreted ; without having to stick stupid things like #+planet: mars in the ; header or risk your earthling readers getting incorrect dates --- I ; suggest that org switch to storing all dates and times in earth zulu ; time or with an offset as it stands, the timezone setting of the ; computer drafting the document must be known to determine what day ; it was etc. users could still draft using <2020-12-16> but C-c C-c ; would add the correct offset? actually this is tricky, because there ; are two cases, one where the location is clear, "napoleon on [1812-01-01]" ; and the other where it is not, the issue is that a single date refers ; to as many different time intervals as there are timezones and without ; knowing the timezone you don't know the date, similar issue if we were ; to try to convert to sols ; https://www.eecis.udel.edu/~mills/missions.html ; https://www.eecis.udel.edu/~mills/ipin.html ; https://en.wikipedia.org/wiki/Timekeeping_on_Mars ; HOWEVER having applied a bit more brain power to the problem, let's ; just assume that clock synchonization will happen between earth and ; mars so that the unix epoch could be synchronized between the frames ; probably with multiple reference stations in free fall and/or in deep ; space to account for gravitaitonal differences etc. so actually the ; only issue would be a practical notational one, or a UI one, since we ; can use timestamp with timezone or just straight epoc for this to work ; earth vs martian year/day is a much harder issue ; the org spec is currently silent on how org will handle dates beyond