From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Nicholas Strauss Newsgroups: gmane.emacs.bugs Subject: bug#20583: calendar-absolute-from-gregorian Date: Fri, 15 May 2015 18:48:02 -0700 Message-ID: References: <577fs9xryr.fsf@fencepost.gnu.org> NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-Trace: ger.gmane.org 1431740966 21485 80.91.229.3 (16 May 2015 01:49:26 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Sat, 16 May 2015 01:49:26 +0000 (UTC) Cc: 20583@debbugs.gnu.org, gjs@ai.mit.edu To: Glenn Morris Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Sat May 16 03:49:14 2015 Return-path: Envelope-to: geb-bug-gnu-emacs@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1YtRE0-0001xk-ST for geb-bug-gnu-emacs@m.gmane.org; Sat, 16 May 2015 03:49:13 +0200 Original-Received: from localhost ([::1]:33364 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YtRE0-0000UR-7X for geb-bug-gnu-emacs@m.gmane.org; Fri, 15 May 2015 21:49:12 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:51151) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YtRDv-0000RY-GO for bug-gnu-emacs@gnu.org; Fri, 15 May 2015 21:49:08 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1YtRDs-0006T8-Aj for bug-gnu-emacs@gnu.org; Fri, 15 May 2015 21:49:07 -0400 Original-Received: from debbugs.gnu.org ([140.186.70.43]:36674) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YtRDs-0006T0-7K for bug-gnu-emacs@gnu.org; Fri, 15 May 2015 21:49:04 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.80) (envelope-from ) id 1YtRDr-0001Ai-3D for bug-gnu-emacs@gnu.org; Fri, 15 May 2015 21:49:03 -0400 X-Loop: help-debbugs@gnu.org Resent-From: Nicholas Strauss Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Sat, 16 May 2015 01:49:02 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 20583 X-GNU-PR-Package: emacs X-GNU-PR-Keywords: notabug wontfix Original-Received: via spool by 20583-submit@debbugs.gnu.org id=B20583.14317408924426 (code B ref 20583); Sat, 16 May 2015 01:49:02 +0000 Original-Received: (at 20583) by debbugs.gnu.org; 16 May 2015 01:48:12 +0000 Original-Received: from localhost ([127.0.0.1]:46646 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.80) (envelope-from ) id 1YtRD2-00019K-0k for submit@debbugs.gnu.org; Fri, 15 May 2015 21:48:12 -0400 Original-Received: from mail-wg0-f46.google.com ([74.125.82.46]:33288) by debbugs.gnu.org with esmtp (Exim 4.80) (envelope-from ) id 1YtRCy-000195-NQ for 20583@debbugs.gnu.org; Fri, 15 May 2015 21:48:09 -0400 Original-Received: by wgin8 with SMTP id n8so132337954wgi.0 for <20583@debbugs.gnu.org>; Fri, 15 May 2015 18:48:03 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; bh=868sIUr3Wc7gPM1xXbpVpbjC9W01mg8WsYvgXEjuevQ=; b=yjf9/Ktk4RXCeD4Vd2ihQvVhkUZ2SCAmH70Zqqvvu00qGlLVIs0PHIffzWTWg+GAz9 d5O5wjFsDbw5/mhJsCvCbFV/FzdK/ZuBUQaY8zIJaZz5vCLpqfCw52ldc52VqJ9PrdiY cz7McKB/uf3og4KFpW82APYjOhBjgNj4Vih/gL5Hy+xJLx6ouq3W9C0lDoXjfG/fLc+k aU17PAPEWfr2+DWZbL1p6/zyylWCoBcbTqf3GbVImoonL1woEtSo4B2sBg/K6Q1C73gc xtQYgKrTwxM0bYNc91SrRp3t0sDq9oMW5CRvahmmEJCb3VbNa8JhruGjympP3Q34QU6J s39A== X-Received: by 10.180.76.231 with SMTP id n7mr2279018wiw.44.1431740882911; Fri, 15 May 2015 18:48:02 -0700 (PDT) Original-Received: by 10.27.100.3 with HTTP; Fri, 15 May 2015 18:48:02 -0700 (PDT) In-Reply-To: <577fs9xryr.fsf@fencepost.gnu.org> X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.15 Precedence: list X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x X-Received-From: 140.186.70.43 X-BeenThere: bug-gnu-emacs@gnu.org List-Id: "Bug reports for GNU Emacs, the Swiss army knife of text editors" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Original-Sender: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.bugs:102861 Archived-At: Hi Glenn, The real point here is that Calendar Systems are instruments and as subject are subject to error (Think like an engineer!). The real world is messy -- Pope Gregory abolished some days, and various countries took their time to jump on the band wagon. I think what Reingold is/was trying to do was to use "absolute" as an internal reference format -- a primary key -- that would correlate all the other calendars. there are other "absolute" choices for internal references. Peter Duffett-Smith took a different approach -- he counts 2415020 days from January 1, 4713 BC until the 1900 epoch, January 0.5, 1900. This crops up in sqlite3 calculations for date() and also common javascript formulas. I am still researching this. If our civilization lasts for any appreciable time, having a consistent calendar will be crucial for keeping a consistent history. I think this helps why I am stressing the astronomy. If an Aztec calendar records an eclipse on a certain day, that's pretty much it. Nick On Fri, May 15, 2015 at 5:54 PM, Glenn Morris wrote: > Nicholas Strauss wrote: > >> Why does (calendar-absolute-from-gregorian '(10 10 1582)) >> return 577731? >> (calendar-generate '(10 1582)) is another example of this >> error. > > It's behaving as designed. It's a utility function that operates on the > basis that today's calendar system is valid for all time. It's not meant > as literally historically accurate, and I think trying to make it so (by > introducing discontinuities at certain dates) would be a mistake. See eg > thread at: > > http://lists.gnu.org/archive/html/emacs-devel/2006-07/msg01008.html