Blueprint changed by أحمد المحمودي (Ahmed El-Mahmoudy): Whiteboard changed to:
as-salamu alaykom, I have been doing some research about the possibility of adding hijri calendar directly into glibc. I found that glibc does support other calendars, such as Buddhist Era (using in Thailand, and Laos I think) and the Japanese Emperors' reigns. That is done by adding definitions for era, era_d_t_fmt, era_d_fmt, era_t_fmt, and alt_digits in the locale [1]. Those definitions modify the behaviour of some time functions (such as strftime) when E and O modifiers are used [2]. The format of 'era' consists of semicolon-separated strings. Each string shall be an era description segment with the format: direction:offset:start_date:end_date:era_name:era_format The descriptions for each field are in [1]. Now the problem is that supported calendars are those which are based on Gregorian calendar. In [3] it says: The E modifier supports alternative date formats, such as the Japanese Emperor's Era, as long as these are based on the Gregorian calendar system. Extending the E modifiers to other date elements may provide an implementation-defined extension capable of supporting other calendar systems, especially in combination with the O modifier. So, I was thinking, that this 'era' can be used for Hijri as follows: 1. For countries that formally use Hijri system, we can add an 'era' definition in their respective locale files. The era field that matters now is 'era_name'. It can be something like "A.H." or even "ه". 2. In glibc C code: a conversion function from Gregorian to Hijri can be added, I was thinking of using the conversion functions that implement the Um-Ul-Qura algorithm since, as far as I know, this is the algorithm that is formally used in Arabia. 3. Somewhere in glibc's time/strftime_l.c & time/strptime_l.c [4], the code should check if era_name is "A.H" or "ه", if that is true, it will call for the conversion function to get the appropriate Hijri date. I hope to get your comments on this suggestion. [1] http://www.opengroup.org/onlinepubs/009695399/basedefs/xbd_chap07.html#tag_07_03_05 [2] http://www.gnu.org/software/libc/manual/html_node/Formatting-Calendar-Time.html#Formatting-Calendar-Time [3] http://www.opengroup.org/onlinepubs/009695399/utilities/date.html [4] http://sources.redhat.com/cgi-bin/cvsweb.cgi/libc/time/strftime_l.c?cvsroot=glibc & http://sources.redhat.com/cgi-bin/cvsweb.cgi/libc/time/strptime_l.c?cvsroot=glibc Here's a log of a chat I had last year on Freenode's #glibc channel regarding this topic: --- Log opened Fri Jan 25 14:53:24 2008 15:06 >ryanarn< AnAnt: It's worth a shot. If you can find a specification talking about an interface you should probably shoot an email to [email protected] and propose it and see what the response is. 15:07 <AnAnt> ryanarn: what do you mean by "would-be presented to user" ? I know that there is some standard of calculating hijri date , called Umm-Ul-Qura timing 15:07 >ryanarn< AnAnt interfaces to change the display format, interfaces to change the date representation etc. 15:08 <AnAnt> ryanarn: ok, I'll research that, thanks for the info. 15:08 <ryanarn> y/w 15:11 >ryanarn< AnAnt something like ISO 8601 http://en.wikipedia.org/wiki/ISO_8601 but with Hijri in mind perhaps. 15:13 -- steelman [[email protected]] has joined #glibc 15:14 <AnAnt> ryanarn: ah, should it be some ISO too ? 15:14 >ryanarn< AnAnt perhaps but I wouldn't be surprised if there wasn't. 15:19 <ryanarn> you need to do your homework, research the standards and go to the mailing list with a well researched plan. 15:20 <AnAnt> what do you mean by a plan ? 15:20 <AnAnt> I mean, what should be provided in that plan ? 15:21 >ryanarn< AnAnt on what interfaces in glibc may need extension, what internals will need extension, the repercussions to user applications, etc. 15:27 <AnAnt> ryanarn: can I provide links from microsoft ? googling gave me results from MSDN 15:28 >ryanarn< AnAnt: that's NOT a good idea. 15:29 <ryanarn> Microsoft is not the pinnacle of standards compliance so you can't hold their implementations up as a baseline. --- Log closed Fri Jan 25 15:32:35 2008 ===== Rajab 2, 1430 (Jun 25 2009) dholbach has directed my attention to a feature request for GLib (probably there will be something in GLib 3.0): http://bugzilla.gnome.org/show_bug.cgi?id=344005 >From there, there is this probably some useful URLs: Era entries for Islamic calendar: http://unicode.org/cldr/repository/common/supplemental/supplementalData.xml?rev=HEAD&content-type=text/vnd.viewcvs-markup (this page is long, just search for the word "islam" there) Unicode Locale Data Markup Language: http://www.unicode.org/reports/tr35 -- Hijri calendar implementation in glibc https://blueprints.launchpad.net/sabily/+spec/hijri-glibc _______________________________________________ Mailing list: https://launchpad.net/~sabily.team Post to : [email protected] Unsubscribe : https://launchpad.net/~sabily.team More help : https://help.launchpad.net/ListHelp
