Create a new calendar

Define a new calendar as a collection of time units. Calendars are the foundation for representing dates and times in terms of human-readable components like years, months, days, hours, minutes, and seconds. Each calendar is defined by specifying the time units it contains, which determine how time values can be interpreted and manipulated.

Usage

new_calendar(..., inherit = NULL, class = character())

Arguments

...

Named time unit class definitions. Each argument should be a time unit class (typically created with S7::new_class()) that inherits from mt_unit or mt_tz_unit. The names define the calendar's fields and are used to access unit constructors (e.g., calendar$year()).

inherit

Optional calendar to inherit time units from. Units defined in ... will override inherited units with the same name.

class

Character vector of additional classes for the calendar object.

Value

A calendar object of class c(class, "mt_calendar"), consisting of a named list containing the specified time unit classes.

Details

Time units are typically S7 class definitions that inherit from mt_unit for standard units, mt_tz_unit for timezone-aware units (civil time), or mt_loc_unit for location-aware units (astronomical time). The calendar object provides a namespace for accessing these unit constructors and defines the relationships between them for calendar arithmetic.

See also

linear_time(), cyclical_time()

Examples

# Create a simple calendar with year and month units
# (inheriting from civil time units for day, hour, minute, second, ...)
cal_simple <- new_calendar(
  year = new_time_unit("tu_year", parent = mt_tz_unit),
  month = new_time_unit("tu_month", parent = mt_tz_unit),
  inherit = cal_time_civil,
  class = "cal_simple"
)

# Create time granules from the calendar
cal_simple$year(1L)
#> <tu_year>
#>  @ n : int 1
#>  @ tz: 'mt_naive' chr NA
cal_simple$month(1L)
#> <tu_month>
#>  @ n : int 1
#>  @ tz: 'mt_naive' chr NA