Newsgroups: php.internals Path: news.php.net Xref: news.php.net php.internals:103112 Return-Path: Delivered-To: mailing list internals@lists.php.net Received: (qmail 18460 invoked from network); 1 Sep 2018 14:07:22 -0000 Received: from unknown (HELO mout.gmx.net) (212.227.15.18) by pb1.pair.com with SMTP; 1 Sep 2018 14:07:22 -0000 Received: from [192.168.2.133] ([91.8.166.159]) by mail.gmx.com (mrgmx002 [212.227.17.190]) with ESMTPSA (Nemesis) id 0MAyZg-1g5uD51k60-009w6v; Sat, 01 Sep 2018 12:09:11 +0200 To: Kurt Weber , internals@lists.php.net References: Message-ID: Date: Sat, 1 Sep 2018 12:09:11 +0200 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: de-DE Content-Transfer-Encoding: 8bit X-Provags-ID: V03:K1:A1iNQkmnyRsk0eVVLAHnuVH5YvCqoxugQcB+JTwb1gagHf4QewP pao+lKB9HfHRYFPkZv9udBzxViElBPprOt/0BjRQyTrlX1S+11lDvxqg/nDd4TxxAoaThTF mhLpSEbjHAiQ73j7PaqiqWlB8c06wQDDhXJWBey+/Rosqs20CMQ7x6nEoBP93Nh/zy7UM9/ ltsve79mXyFZkqyKZuXWA== X-UI-Out-Filterresults: notjunk:1;V01:K0:ZfYXntJdcBY=:wqbRhdKWPmEva7KWVGpXQm 17ptZW1ITGyuFJhijIL6s4I92Tnj6u9VAiGUnR9DGrCaRsO/AVANFSaiDx0U3a8B/ZmGIcGdh Ze69/fgBYMM+yQ/sIKsz0LYdH0mamIle2nyDjqAsXjeS8/edSsiwq2iCwVl2qdiC85uMhMcPt bLc5O3dQI1cSyIBwiuF1uyvNTA7vEDi1ttLMmYr/+GrllzHpv7zjdR8tfgOxWjUlzNt6i45Pc xJLxNbqaKJQazf6QI5EfxiqocR7h3WPyKH0+6PUTNePs8WJf6baFkNeOZ2u2Mrnd2ppuxohsb GWvHOl3xaUgkJRNkGH08RLYoa/syJ8CXzHoYMzIn2BnDLPY2BJwID/bFSTTU1CAtqT/RLmwvm vw7q0PRrgfSh7nTUFQeOIW4ezEZKW3CLZJ/IUOqdtdgMZdt0OCxalxpyvh8oPQ6u6QY1kDA6P IZmbJKqkNzj7cP+AqrkCb1EshY6zxrbdLhmtmMuQDqvy+f0Qf/Jr5A4X++WKM9vDtcusrK6A9 e4J3lhDst0y/YWHvngin+RzGbL5BuhHXjzSm3UZ66SZXW15L9OdSVbN/ymiUDbiyCZnJjD8pk XcvF+cO4uxaoSskUHrwAWbqfzaoJCFXs5cGLI1BaBOJ+d51RJwaeuIAiNRIVNm/UXxx+B6RfZ /x89lOAMO6DRrdnx0tx24TxqwKyTIWAwA/BJnn9Gi1MaRf+KbqHwhLo+hunA5+gqy8fQOzzgv TZEg6lesk2jDa7aqhWJZbMf3acEvj7WXbCBLsJV+EEjuGDUyAMDWdklBd3RBaOTA2jfbWAUku hX+Onpn Subject: Re: Proposal: Add tabular Islamic calendar to calendar conversion functions From: cmbecker69@gmx.de ("Christoph M. Becker") On 30.08.2018 at 22:33, Kurt Weber wrote: > The calendar conversion functions currently support (via Julian Day > Numbers as an intermediary) conversion between Gregorian, Julian, > Hebrew, and French Revolutionary calendars. Conspicuously absent is > the Islamic calendar. A comment in ext/calendar/sdncal.h seems to > suggest that the original author(s) intended to implement at some > point, but never got around to it. > > The Islamic calendar offers some complications because in most > places and communities that use it for religious purposes, the switch > from one month to the next is based on actually observing the moon in > the proper phase. In theory the date of this change can be > calculated (and indeed the early Islamic surge in study of astronomy > was motivated by the wish to know about when they should start > looking), but tradition still demands that it be actually observed > before a change is made--the actual impact of this is that local sky > or weather conditions can sometimes interfere with the observation in > a particular jurisdiction, meaning that often it comes a day or so > later than when it otherwise would. > > Consequently, what I'm proposing is the Tabular Islamic Calendar, > which was specifically created to be predictable and calculable. It > is of limited use for religious purposes (and documentation should > probably be clear about this), but it would be useful for, e.g. > people working with historical documents from Islamic communities or > groups (In fact, this is how I came to this problem--I am working on > a Ph.D. in Russian history, and as a side project I'm developing a > PHP-backed website to manage research notes and other information; > because I work on prerevolutionary Russia I'm very familiar with the > issue of needing to convert between calendar systems (in my case, > Julian and Gregorian), and my colleagues working on Islamic history > often have similar issues.). > > Tabular Islamic calendar is not ideal, but it seems like the only > realistic option for automated conversion. > > As far as implementation goes, I could do it. I've already > implemented conversion one way, before I stopped work in case there > were issues that come up in this discussion that I hadn't foreseen > (unfortunately, that happened roughly at the time the mailing list > server seems to have died, so it's been paused for a couple of > weeks). So all I'd have to do is the other direction, and it'd be > ready to test. Thanks! I'm not opposed to this suggestion. There is the suspended feature request #27453[1], and I agree that even a tabular Islamic calendar would be much more useful than the French Revolunationary calendar. Presently, I see three counter-arguments: (a) already supported by ext/intl (b) maintenance burden (c) opening up a can of worms Ad (a): Islamic calendars are already supported by the intl extension[2]. Even though ext/intl supports an Islamic calendar, that doesn't prohibit that ext/calendar also does, though, since they are independent extensions (cf. ext/mbstring, ext/iconv, ext/recode). Ad (b): if nobody else is willing to step up as maintainer of ext/calendar[3], I'd be willing to do so. I've already did some maintenance[4] so far. Ad (c): this is somewhat of a problem. I can easily imagine folks requesting support for specific Islamic calendars which would require (up-to-date) data, what could easily blow ext/calendar out of proportion. Also I can imagine people coming up with “the FOO calendar is used more widely than the tabular Islamic calendar, so it should be supported as well” argument. Especially due to (c) I suggest to go through the RFC process[5], whereby the RFC could also set some precendence/rules for potentially further calendar systems (i.e. what ext/calendar may support, and what not). [1] [2] [3] [4] [5] -- Christoph M. Becker