Module chinese_based

Chinese-like lunar calendars (Chinese, Dangi)

Structs

Chinese

A type implementing ChineseBased for the Chinese calendar

ChineseFromFixedResult

chinese_based_date_from_fixed returns extra things for use in caching

Dangi

A type implementing ChineseBased for the Dangi (Korean) calendar

YearBounds

Marks the bounds of a lunar year

Constants

CHINESE_EPOCH 🔒

CHINESE_EPOCH_ISO 🔒

CHINESE_LOCATION_POST_1929 🔒

CHINESE_LOCATION_PRE_1929 🔒

FIXED_1908 🔒

FIXED_1912 🔒

FIXED_1954 🔒

FIXED_1961 🔒

KOREAN_ELEVATION 🔒

KOREAN_EPOCH 🔒

KOREAN_EPOCH_ISO 🔒

KOREAN_LATITUDE 🔒

KOREAN_LOCATION_1908 🔒

KOREAN_LOCATION_1912 🔒

KOREAN_LOCATION_1954 🔒

KOREAN_LOCATION_1961 🔒

KOREAN_LOCATION_ORIGINAL 🔒

KOREAN_LONGITUDE 🔒

MAX_ITERS_FOR_MONTHS_OF_YEAR 🔒

UTC_OFFSET_1908 🔒

UTC_OFFSET_1912 🔒

UTC_OFFSET_1954 🔒

UTC_OFFSET_1961 🔒

UTC_OFFSET_ORIGINAL 🔒

The Korean Dangi calendar relies on knowing the current day at the moment of a new moon; however, this can vary depending on location. As such, new moon calculations are based on the time in Seoul. Before 1908, local time was used, represented as UTC+(3809/450 h). This changed multiple times as different standard timezones were adopted in Korea. Currently, UTC+9h is used.

UTC_OFFSET_POST_1929 🔒

UTC_OFFSET_PRE_1929 🔒

The Chinese calendar relies on knowing the current day at the moment of a new moon; however, this can vary depending on location. As such, new moon calculations are based on the time in Beijing. Before 1929, local time was used, represented as UTC+(1397/180 h). In 1929, China adopted a standard time zone based on 120 degrees of longitude, meaning from 1929 onward, all new moon calculations are based on UTC+8h.

Traits

ChineseBased

The trait ChineseBased is used by Chinese-based calendars to perform computations shared by such calendar. To do so, calendars should:

Functions

bind_winter_solstice 🔒

This function forces the RataDie to be on December 20, 21, 22, or 23. It was created for practical considerations and is not in the text.

chinese_based_date_from_fixed

Get a chinese based date from a fixed date, with the related ISO year

days_in_month

Returns the number of days in the given month after the given new_year. Also returns the RataDie of the new moon beginning the next month.

days_in_prev_year

Given a new year, calculate the number of days in the previous year

days_in_provided_year

Calculated the numbers of days in the given year

days_until_month

Given the new year and a month/day pair, calculate the number of days until the first day of the given month

fixed_mid_year_from_year

Get a RataDie in the middle of a year.

get_leap_month_from_new_year

Given that new_year is the first day of a leap year, find which month in the year is a leap month.

is_leap_year

Whether this year is a leap year

last_month_day_in_year

The last month and day in this year

major_solar_term_from_fixed 🔒

Get the current major solar term of a fixed date, output as an integer from 1..=12.

midnight 🔒

Universal time of midnight at start of a Moment’s day at the observation location

month_days

Returns the number of days in the given (year, month).

month_structure_for_year

Returns the length of each month in the year, as well as a leap month index (1-indexed) if any.

new_moon_before 🔒

The fixed date in standard time at the observation location of the previous new moon before a given Moment.

new_moon_on_or_after 🔒

The fixed date in standard time at the observation location of the next new moon on or after a given Moment.

new_year_in_sui 🔒

Determines the fixed date of the lunar new year given the start of its corresponding solar year (歲), which is also the winter solstice

new_year_on_or_before_fixed_date 🔒

Get the fixed date of the nearest Lunar New Year on or before a given fixed date. This function also returns the solstice following a given date for optimization (see #3743).

winter_solstice_on_or_before 🔒

Get the fixed date of the nearest winter solstice, in the Chinese time zone, on or before a given fixed date.