Module:Calendrical Calculations/doc

This module is a Lua translation of the Lisp code in Appendix D of Calendrical Calculations: The Ultimate Edition by Nachum Dershowitz and Edward Reingold. It allows any date to be converted between any two of the Rata Die, Modified Julian Date, Julian day, Egyptian, Armenian, Akan, Gregorian, Julian, Roman, Coptic, Ethiopian, ISO week date, Icelandic, Islamic, Hebrew, Hindu, Mayan, Aztec, Balinese pawukon, Persian/Solar Hijri, Baha'i, French Republican, Babylonian, Samaritan, Chinese, Japanese, and Tibetan calendars

Usage

For most of the calendars above, two functions are implemented: one that converts a fixed (i.e. Rata Die) date into a date in the calendar, and another that converts a date into the calendar into a fixed date. For a calendar named X, these would be called x_from_fixed and fixed_from_x respectively. Therefore, to convert a date in calendar X to calendar Y, the date must be converted from x to Rata Die using fixed_from_x(x_date), then the result converted to y using y_from_fixed. For example, the date 12 November 1945 in the Gregorian calendar could be converted to the Julian calendar like this:

{{#invoke:Calendrical Calculations|fixed_from_gregorian|1945|11|12}} → 710347

{{#invoke:Calendrical Calculations|julian_from_fixed|710347}} → 1945-10-30

There is a convert function that automatically combines the two steps like this:

{{#invoke:Calendrical Calculations|convert|gregorian|julian|1945|11|12}} → 1945-10-30

Either method correctly returns 30 October 1945. The convert function makes calendar names case-insensitive, and replaces spaces and dashes with underscores, so that Hindu Lunar, hindu_lunar, hindu-lunar, etc will all work.

Isolating elements in arrays

Most x_from_fixed functions return arrays. To isolate one element in the array, an index= parameter could be passed. For example, to get just the day of the month in the conversion above, an index=3 parameter can be added like this:

{{#invoke:Calendrical Calculations|julian_from_fixed|710347|index=3}} → 30

Likewise, index=2 would return only the month number, and index=1 would return only the year.

Accepted parameters

It should be noted that all inputted parameters must be numerical, and all outputs are also numerical. For boolean values, 0 is used as false and 1 as true. For months, the helper templates listed below convert the month numbers into names.

Not all of the fixed_from_x functions accept parameters in the form of year, month, day, and likewise not all the x_from_fixed functions return outputs in that format. Below is a list of, for each calendar, which parameters its fixed_from_ function accepts and its _from_fixed function returns:

Calendar	Functions	Parameters/returned values
Rata Die	rd	date
Modified Julian Date	fixed_from_mjd / mjd_from_fixed	mjd
Julian day	fixed_from_jd / jd_from_fixed	jd
Egyptian	fixed_from_egyptian / egyptian_from_fixed	year, month, day
Armenian	fixed_from_armenian / armenian_from_fixed	year, month, day
Gregorian	fixed_from_gregorian / gregorian_from_fixed	year, month, day
Julian	fixed_from_julian / julian_from_fixed	year, month, day
Roman	fixed_from_roman / roman_from_fixed	year, month, event, count, leap
Coptic	fixed_from_coptic / coptic_from_fixed	year, month, day
Ethiopian	fixed_from_ethiopic / ethiopic_from_fixed	year, month, day
ISO week date	fixed_from_iso / iso_from_fixed	year, week, day
Icelandic	fixed_from_icelandic / icelandic_from_fixed	year, season, week, weekday
Islamic	fixed_from_islamic / islamic_from_fixed	year, month, day
Observational Islamic	fixed_from_observational_islamic / observational_islamic_from_fixed	year, month, day
Saudi Islamic	fixed_from_saudi_islamic / saudi_islamic_from_fixed	year, month, day
Hebrew	fixed_from_hebrew / hebrew_from_fixed	year, month, day
Observational Hebrew	fixed_from_observational_hebrew / observational_hebrew_from_fixed	year, month, day
Old Hindu solar	fixed_from_old_hindu_solar / old_hindu_solar_from_fixed	year, month, day
Old Hindu lunar	fixed_from_old_hindu_lunar / old_hindu_lunar_from_fixed	year, month, leap month, day
Modern Hindu solar	fixed_from_hindu_solar / hindu_solar_from_fixed	year, month, day
Modern Hindu lunar	fixed_from_hindu_lunar / hindu_lunar_from_fixed	year, month, leap month, day, leap day
Full-moon Hindu lunar	fixed_from_hindu_fullmoon / hindu_fullmoon_from_fixed	year, month, leap month, day, leap day
Astronomical Hindu solar	fixed_from_astro_hindu_solar / astro_hindu_solar_from_fixed	year, month, day
Astronomical Hindu lunar	fixed_from_astro_hindu_lunar / astro_hindu_lunar_from_fixed	year, month, leap month, day, leap day
Maya Long Count	fixed_from_mayan_long_count / mayan_long_count_from_fixed	baktun, katun, tun, uinal, kin
Persian	fixed_from_persian / persian_from_fixed	year, month, day
Arithmetic Persian	fixed_from_arithmetic_persian / arithmetic_persian_from_fixed	year, month, day
Baháʼí	fixed_from_bahai / bahai_from_fixed	major, cycle, year, month, day
Astronomical Baháʼí	fixed_from_astro_bahai / astro_bahai_from_fixed	major, cycle, year, month, day
French Republican	fixed_from_french / french_from_fixed	year, month, day
Arithmetic French Republican	fixed_from_arithmetic_french / arithmetic_french_from_fixed	year, month, day
Babylonian	fixed_from_babylonian / babylonian_from_fixed	year, month, leap month, day
Samaritan	fixed_from_samaritan / samaritan_from_fixed	year, month, day
Chinese	fixed_from_chinese / chinese_from_fixed	cycle, year, month, leap month, day
Japanese	fixed_from_japanese / japanese_from_fixed	cycle, year, month, leap month, day
Korean	fixed_from_korean / korean_from_fixed	cycle, year, month, leap month, day
Tibetan	fixed_from_tibetan / tibetan_from_fixed	year, month, leap month, day, leap day

Helper templates

Because most conversions will be from the Gregorian calendar to another calendar, there are several helper templates which simplify the usage of this module by taking a Gregorian year, month and day, and converting it to the given calendar, and handling the formatting. If not given a date, they default to using the current date in UTC+00. Below is a list of these helper templates and their documentation guides:

• Akan calendar: {{AKANCALENDAR}}
• Armenian calendar: {{ARMENIANDATE}}
• Aztec calendar: {{AZTECCALENDAR}}
• Babylonian calendar: {{BABYLONIANDATE}}
• Balinese pawukon calendar: {{BALINESEPAWUKONCALENDAR}}
• Bengali calendar: {{BENGALIDATE}}
• Chinese calendar: {{CHINESECALENDAR}}
• Coptic calendar: {{COPTICDATE}}
• Egyptian calendar: {{EGYPTIANDATE}}
• Ethiopian calendar: {{ETHIOPIANDATE}}
• French Republican calendar: {{FRENCHREVOLUTIONARYDATE}}
• Hindu calendar: {{HINDUCALENDAR}}
• Icelandic calendar: {{ICELANDICDATE}}
• Japanese calendar: {{JAPANESECALENDAR}}
• Julian calendar: {{JULIANCALENDAR}}
• Julian day: {{JD}}
• Korean calendar: {{KOREANCALENDAR}}
• Maya calendar: {{MAYANCALENDAR}}
• Rata Die: {{RD fixed}}
• Roman calendar: {{ROMANDATE}}
• Tibetan calendar: {{TIBETANDATE}}

The ISO week date, Hebrew, Islamic, Solar Hijri calendars do not have helper functions because MediaWiki's #time function already provides conversions for them, in its o, xj, xm and xi portions respectively. A usage guide for this function can be found here.

Template:Infobox calendar date

This module is used by {{Infobox calendar date}} to convert the current date, or any given date, into many different calendars. Its documentation guide can be read here.

AI Declaration

LLM aid was used to translate the Lisp code in the book to Lua.

Source

• Dershowitz, Nachum; Reingold, Edward M. (2018). Calendrical Calculations (Fourth ed.). Cambridge: Cambridge University Press. ISBN 9781107057623. OCLC 1030959487.