Adds :year, :quarter, :month, :week increments

These functions support CalendarInterval

Identifies that the calendar is month based.

@spec calendar_year(
  year :: Cldr.Calendar.year(),
  month :: Cldr.Calendar.month(),
  day :: Cldr.Calendar.day()
) :: year :: Calendar.year() | {:error, {module(), String.t()}}

Returns the calendar year as displayed on rendered calendars.

Defines the CLDR calendar type for this calendar.

This type is used in support of Cldr.Calendar.localize/3. Currently only :gregorian or :japanese are supported.

@spec cyclic_year(
  year :: Cldr.Calendar.year(),
  month :: Cldr.Calendar.month(),
  day :: Cldr.Calendar.day()
) :: year :: Calendar.year() | {:error, {module(), String.t()}}

Returns the cyclic year as displayed on rendered calendars.

Returns {year, month, day} calculated from the number of iso_days.

Returns the number of days since the calendar epoch for a given year-month-day

@spec day_of_era(
  year :: Cldr.Calendar.year(),
  month :: Cldr.Calendar.month(),
  day :: Cldr.Calendar.day()
) ::
  {day :: Cldr.Calendar.day(), era :: Cldr.Calendar.era()}
  | {:error, {module(), String.t()}}

Calculates the day and era from the given year, month, and day.

@spec day_of_week(
  year :: Cldr.Calendar.year(),
  month :: Cldr.Calendar.month(),
  day :: Cldr.Calendar.day(),
  :default | atom()
) ::
  {day_of_week :: Calendar.day_of_week(),
   first_day_of_week :: Calendar.day_of_week(),
   last_day_of_week :: Calendar.day_of_week()}
  | {:error, {module(), String.t()}}

Calculates the day of the week from the given year, month, and day. It is an integer from 1 to 7, where 1 is Monday and 7 is Sunday.

@spec day_of_year(
  year :: Cldr.Calendar.year(),
  month :: Cldr.Calendar.month(),
  day :: Cldr.Calendar.day()
) :: day :: Calendar.day() | {:error, {module(), String.t()}}

Calculates the day of the year from the given year, month, and day.

@spec days_in_month(month :: Cldr.Calendar.month()) ::
  days ::
  Calendar.day() | {:error, {module(), String.t()}} | {:ambiguous, Range.t()}

Returns how many days there are in the given month.

If the days in month cannot be determined without knowning the year and error tuple is returned.

@spec days_in_month(year :: Cldr.Calendar.year(), month :: Cldr.Calendar.month()) ::
  days ::
  Calendar.day() | {:error, {module(), String.t()}} | {:ambiguous, Range.t()}

Returns how many days there are in the given year-month.

Returns the number days in a week.

@spec days_in_year(year :: Cldr.Calendar.year()) ::
  days :: Calendar.day() | {:error, {module(), String.t()}}

Returns the number days in a given year.

@spec extended_year(
  year :: Cldr.Calendar.year(),
  month :: Cldr.Calendar.month(),
  day :: Cldr.Calendar.day()
) :: year :: Calendar.year() | {:error, {module(), String.t()}}

Returns the extended year as displayed on rendered calendars.

Returns the number of iso_days that is the first day of the given year for this calendar.

@spec iso_week_of_year(
  year :: Cldr.Calendar.year(),
  month :: Cldr.Calendar.month(),
  day :: Cldr.Calendar.day()
) ::
  {year :: Calendar.year(), week :: Cldr.Calendar.week()}
  | {:error, {module(), String.t()}}

Calculates the ISO week of the year from the given year, month, and day. It is an integer from 1 to 53.

Returns the number of iso_days that is the last day of the given year for this calendar.

@spec leap_year?(year :: Cldr.Calendar.year()) :: boolean()

Returns if the given year is a leap year.

Returns a t:Date.Range representing a given month of a year.

@spec month_of_year(
  year :: Cldr.Calendar.year(),
  month :: Cldr.Calendar.month(),
  day :: Cldr.Calendar.day()
) :: month :: Calendar.month() | {:error, {module(), String.t()}}

Calculates the month of the year from the given year, month, and day. It is an integer from 1 to 12.

@spec naive_datetime_from_iso_days(Calendar.iso_days()) ::
  {Calendar.year(), Calendar.month(), Calendar.day(), Calendar.hour(),
   Calendar.minute(), Calendar.second(), Calendar.microsecond()}

Converts the t:Calendar.iso_days format to the datetime format specified by this calendar.

@spec naive_datetime_to_iso_days(
  Calendar.year(),
  Calendar.month(),
  Calendar.day(),
  Calendar.hour(),
  Calendar.minute(),
  Calendar.second(),
  Calendar.microsecond()
) :: Calendar.iso_days()

Returns the t:Calendar.iso_days format of the specified date.

@spec periods_in_year(year :: Cldr.Calendar.year()) :: Calendar.month()

Calculates the number of period in a given year. A period corresponds to a month in month-based calendars and a week in week-based calendars.

Adds an increment number of date_parts to a year-month-day.

date_part can be :years, :quarters :months or :days.

Returns a t:Date.Range representing a given quarter of a year.

@spec quarter_of_year(
  year :: Cldr.Calendar.year(),
  month :: Cldr.Calendar.month(),
  day :: Cldr.Calendar.day()
) :: quarter :: Cldr.Calendar.quarter() | {:error, {module(), String.t()}}

Calculates the quarter of the year from the given year, month, and day. It is an integer from 1 to 4.

@spec related_gregorian_year(
  year :: Cldr.Calendar.year(),
  month :: Cldr.Calendar.month(),
  day :: Cldr.Calendar.day()
) :: year :: Calendar.year() | {:error, {module(), String.t()}}

Returns the related gregorain year as displayed on rendered calendars.

@spec shift_date(Calendar.year(), Calendar.month(), Calendar.day(), Duration.t()) ::
  {Calendar.year(), Calendar.month(), Calendar.day()}

Shifts a date by given duration.

@spec shift_naive_datetime(
  Calendar.year(),
  Calendar.month(),
  Calendar.day(),
  Calendar.hour(),
  Calendar.minute(),
  Calendar.second(),
  Calendar.microsecond(),
  Duration.t()
) ::
  {Calendar.year(), Calendar.month(), Calendar.day(), Calendar.hour(),
   Calendar.minute(), Calendar.second(), Calendar.microsecond()}

Shifts a naive date time by given duration.

@spec shift_time(
  Calendar.hour(),
  Calendar.minute(),
  Calendar.second(),
  Calendar.microsecond(),
  Duration.t()
) ::
  {Calendar.hour(), Calendar.minute(), Calendar.second(),
   Calendar.microsecond()}

Shifts a time by given duration.

Determines if the date given is valid according to this calendar.

Returns a t:Date.Range representing a given week of a year.

@spec week_of_month(
  year :: Cldr.Calendar.year(),
  month :: Cldr.Calendar.week(),
  day :: Calendar.day()
) ::
  {month :: Calendar.month(), week :: Cldr.Calendar.week()}
  | {:error, {module(), String.t()}}

Calculates the week of the month from the given year, month, and day. It is an integer from 1 to 5.

@spec week_of_year(
  year :: Cldr.Calendar.year(),
  month :: Cldr.Calendar.month(),
  day :: Cldr.Calendar.day()
) ::
  {year :: Calendar.year(), week :: Cldr.Calendar.week()}
  | {:error, {module(), String.t()}}

Calculates the week of the year from the given year, month, and day. It is an integer from 1 to 53.

@spec weeks_in_year(year :: Cldr.Calendar.year()) ::
  {weeks :: Calendar.week(), days_in_last_week :: Calendar.day()}
  | {:error, {module(), String.t()}}

Returns the number weeks in a given year.

Note that for Gregorian month-based calendars the number of weeks returned will be 53 (not the sometimes expected 52) since there is always a week 53 with 1 or 2 (in a leap year) additional days in the last week.

Arguments

• year is any Calendar.year/0

Returns

• {weeks_in_year, days_in_last_week}

Example

iex> Cldr.Calendar.Gregorian.weeks_in_year(2019)
{53, 1}

iex> Cldr.Calendar.Gregorian.weeks_in_year(2020)
{53, 2}copy

Returns a t:Date.Range representing a given year.

@spec year_of_era(Cldr.Calendar.year()) ::
  {year :: Calendar.year(), era :: Cldr.Calendar.era()}

Calculates the year and era from the given year.

The ISO calendar has two eras: the current era which starts in year 1 and is defined as era "1". And a second era for those years less than 1 defined as era "0".

@spec year_of_era(
  year :: Cldr.Calendar.year(),
  month :: Cldr.Calendar.month(),
  day :: Cldr.Calendar.day()
) ::
  {year :: Calendar.year(), era :: Cldr.Calendar.era()}
  | {:error, {module(), String.t()}}

Calculates the year and era from the given year, month and day.

The ISO calendar has two eras: the current era which starts in year 1 and is defined as era "1". And a second era for those years less than 1 defined as era "0".