[issue31895] Native hijri calendar support

[Terry J. Reedy]

Change by Terry J. Reedy :


--
title: How to implement api in python website -> Native hijri calendar support

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue31895] Native hijri calendar support

[Terry J. Reedy]

Terry J. Reedy  added the comment:

Haneef, thank you for the explanation.  Any such addition would need a PEP.  
But I agree with Marc-Andre that supporting the multitude of calendars is out 
of scope for the stdlib.  So I suspect such a PEP would be rejected, with the 
suggestion already given here, that this belongs on PyPI.  An existing example 
is the time module of the astropy module,
http://docs.astropy.org/en/stable/time/index.html .

I could be wrong, but I have a vague impression that expanding calendar support 
has been requested and rejected before.  We have enough to do properly 
supporting the existing time, datetime, and calendar modules.

--
nosy: +terry.reedy
resolution:  -> rejected
stage:  -> resolved
status: open -> closed

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue31895] Native hijri calendar support

[Marc-Andre Lemburg]

Marc-Andre Lemburg  added the comment:

There are other PyPI packages available for this specific calendar as well, 
e.g. https://pypi.python.org/pypi/umalqurra/

Perhaps you could send Neil a PR to make the calculation more accurate ?!

In any case, the stdlib is not meant to cover everything, only a basic subset 
of functionality, so adding support for more than just one calendar is out of 
scope.

--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue31895] Native hijri calendar support

[Haneef]

Haneef  added the comment:

Thanks @steven.daprano, yeah, it would be good to have support for other 
calendars as well.

In my case, I use the Hijri Umm al-Qura, Gregorian and obviously UnixTime 
calendars.

You're right, maybe it would be wiser to implement it in the PyPi first and 
then move it to a standard Python library.

@Lemburg, I checked out the PyPi convertdate library, as Gareth mentioned, it 
doesn't specify which Islamic calendar it is implementing and had a look at the 
code, it doesn't look like Umm al-Qura. It seems to be a very roughly 
calculated Tabular Lunar Calendar (with Hijrah as the reference point), no 
where near accurate to the actual lunar cycles.


@Gareth
To explain Islamic Hijri Calendar in short, it is basically a sighted Lunar 
calendar, which has to be sighted at the end of every month to determine the 
beginning of the next month. Therefore, it is not possible to determine the 
dates in future (beyond 29th of the month). Every month could be 29 or 30 days. 
There are 12 months and 354 days in a year.
However, to solve this issue, Muslim astronomers and Scholars over the course 
of History (1400years) have used two different types of Hijri calendars; one 
sighted and another calculated. The sighted version of the calendar is accurate 
but cannot go beyond 29th of the current month.
The astronomically calculated version could go up-to a fixed period which the 
astronomers have calculated. The calculated/civil calendar is used for Visas, 
deeds, bank statements, appointments and other civil matters in their 
respective countries.

One of the predominantly used and astronomically calculated Hijri calendars is 
the Umm al-Qura Hijri calendar. It was calculated by scholars & astronomers at 
the Umm al-Qura (Makkah) University.

Sorry about the long post, hope this helps.

--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue31895] Native hijri calendar support

[Gareth Rees]

Gareth Rees  added the comment:

convertdate does not document which version of the Islamic calendar it uses, 
but looking at the source code, it seems that it uses a rule-based calendar 
which has a 30-year cycle with 11 leap years. This won't help Haneef, who wants 
the Umm al-Qura calendar.

--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue31895] Native hijri calendar support

[Marc-Andre Lemburg]

Marc-Andre Lemburg  added the comment:

I agree with Steven: It's best to use a PyPI package for calendar support such 
as https://pypi.python.org/pypi/convertdate/.

We only have the standard Gregorian calendar support in datetime and calendar 
modules.

--
nosy: +lemburg

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue31895] Native hijri calendar support

[Gareth Rees]

Gareth Rees  added the comment:

It is a substantial undertaking, requiring a great deal of expertise, to 
implement the Islamic calendar. The difficulty is that there are multiple 
versions of the calendar. In some places the calendar is based on human 
observation of the new moon, and so a database of past observations is needed 
(and future dates can't be represented). In other places the time of 
observability of the new moon is calculated according to an astronomical 
ephemeris (and different ephemerides are used in different places and at 
different times).

--
nosy: +g...@garethrees.org

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue31895] Native hijri calendar support

[Steven D'Aprano]

Steven D'Aprano  added the comment:

Python 2.7 is in feature freeze, so 3.7 is the absolute earliest this could be 
introduced. Given how close we are to 3.7 feature freeze, 3.8 is more likely.

I don't think we would have any objections to supporting hijri calendar, in 
principle, but as a practical matter I expect that none of the core developers 
are probably qualified to write, review, support and maintain it. (I could be 
wrong, of course.) And what interface is required?

I'm not convinced that the datetime module is the right place for this. In the 
long run, we should expect that Python may support multiple calendars: Western, 
Arabic, Jewish, Asian calendars, and more. I think that would make datetime too 
big and clunky.

I think the best approach would be to provide a third-party package on PyPI, 
and once it has proven itself, it could be proposed for the standard library.

--
nosy: +steven.daprano
versions:  -Python 2.7

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue31895] Native hijri calendar support

[Haneef]

Haneef  added the comment:

This feature can be added to the 
(datetime.py)[https://docs.python.org/3/library/datetime.html], Java has done a 
similar move and it makes the whole process a lot easier.

The Hijri calendar is used across the globe by various websites and developers, 
some have even made libraries.

--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue31895] Native hijri calendar support

[Haneef]

New submission from Haneef :

There should be native support for converting between Hijri (Umm al-Qura), 
Gregorian, Julian and UnixTime calendars.

Many big players have included native support for Hijri calendar in their SDKs 
and software. Below are some:

(Java Hijri calendar 
support)[https://docs.oracle.com/javase/8/docs/api/java/time/chrono/HijrahChronology.html]
(Apple supports the Hijri calendar in 5 of their SDKs (Software Development 
Kits))[https://developer.apple.com/documentation/foundation/calendar.identifier]
(Microsoft Windows supports Hijri calendar 
naively)[https://www.microsoft.com/middleeast/msdn/ArabicCalendar.aspx]
(Microsoft Office has native 
support)[https://blogs.technet.microsoft.com/office_global_experience/2010/01/13/um-al-qura-calendar-support-in-office-2010/]
(Android Hijri calendar 
support)[https://developer.android.com/reference/android/icu/util/IslamicCalendar.html]
(Google Calendar allows Hijri calendar as an alternate 
calendar)[https://www.maketecheasier.com/display-alternate-calendar-google-calendar/]

--
messages: 305199
nosy: haneef95
priority: normal
severity: normal
status: open
title: Native hijri calendar support
type: enhancement
versions: Python 2.7, Python 3.8

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com