Add Arabic calendars

[tychonievich]

Greg suggested we add the jalali (Arabic) and hijri (Persian) calendars. He suggests the following calendar and month tags:

JALALI - FARVA, ORDIB, KHORD, TIR, MORDA, SHAHR, MEHR, ABAN, AZAR, DEY, BAHMA, ESFAN HIJRI - MUHAR, SAFAR, RABIA, RABIT, JUMAA, JUMAT, RAJAB, SHAAB, RAMAD, SHAWW, DHUAQ, DHUAH

(see https://groups.google.com/g/gedcomgeneral/c/WcRBnr7XFpg for the original suggestion)

[elyoh]

It would be great to see additional standard calendars supported although the above proposal needs some further discussion.

For example:

jalali (Arabic) and hijri (Persian) calendars

is quite confusing.

As far as I understand, the Jalali calendar was adoped by Iran, and is commonly referred to as the Persian / Iranian Hijri / Shamsi Hijri calendar too. More precisely, it is an astronomical solar Hijri calendar and uses the first set of month names given. The other set of month names are used with various forms of lunar Hijri calendar (not the Persian calendar).

It would be beneficial to define an abstract set of lunar Hijri and solar Hijri months which can then be used in various real world calendars (e.g. Persian, Islamic, Umm al-Qura calendars). The tags for these calendars must precisely define the calendar rules so that receiving systems can carry out calculatations with the dates.

A suitable epoch marker would also need to be defined for both calendars to allow for proleptic dates before Hijra. An epoch name of BH would seem a sensible choice.

[elyoh]

For reference, the month tags along with the transliterated and original forms.

Solar Hijri month names (romanized form of the Persian month names):

Code	Name
FARVA	Farvardīn (فروردین)
ORDIB	Ordībehešht (اردیبهشت)
KHORD	Khordād (خرداد)
TIR	Tīr (تیر)
MORDA	Mordād (مرداد)
SHAHR	Shahrīvar (شهریور)
MEHR	Mehr (مهر)
ABAN	Ābān (آبان)
AZAR	Āzar (آذر)
DEY	Dey (دی)
BAHMA	Bahman (بهمن)
ESFAN	Esfand (اسفند)

Lunar Hijri month names

Code	Name
MUHAR	Muḥarram (المُحَرَّم)
SAFAR	Ṣafar (صَفَر)
RABIA	Rabī I (رَبيع الاوَّل)
RABIT	Rabī II (رَبيع الآخِر)
JUMAA	Jumādā I (جُمادى الأولى)
JUMAT	Jumādā II (جُمادى الآخِرة)
RAJAB	Rajab (رَجَب)
SHAAB	Sha‘bān (شَعبان)
RAMAD	Ramaḍān (رَمَضان)
SHAWW	Shawwāl (شَوّال)
DHUAQ	Dhū al-Qa‘da (ذو القَعدة)
DHUAH	Dhū al-Ḥijja (ذو الحِجّة)

[emyoulation]

What other calendars are being considered?

Gramps currently has: Gregorian, Julian, Hebrew. French Republican. Persian, Islamic, Swedish (only valid for 12 years) calendars.

[tychonievich]

What other calendars are being considered?

Thus far, the GEDCOM steering committee has not scheduled the addition of any specific calendars, but I think in principle we're open to adding as many as we can come to consensus on the definition of. In addition to those already mentioned by emyoulation and elyoh in this thread, we've had preliminary conversations about several Tibetan and Hindu calendars because of their multiple day numbering systems (Tibetan khyim, tshes, nyin, and gza'; Hindu divasa and tithi). So far all of those conversations have focused on "can we represent them eventually," not "let's plan to add them soon".

We know that calendars are easy to get wrong and hard to fix once they've been incorrectly characterized in a standard. We'd welcome you adding details about your implementation of the calendars already discussed in this issue to this issue and opening new issues for other calendars.

[emyoulation]

As an unlikely-to-be-added outlier calendar, could you add a Quaker calendar to the list?

It is a variant of the Gregorian/Julian mess. But with some tweaks for the aversion to pagan eponyms. (So, the date 14 vii 1720 O.S. means 14th day, 8th month of 120 Old Style. And the 8th month would've been October in that variation of the Julian calendar since the year started in February.)