almanac (version 0.1.1)

recur_on_easter: Recur on easter

Description

recur_on_easter() is a special helper to recur on Easter. Easter is particularly difficult to construct a recurrence rule for. Using offset, this can also be used to generate a recurrence rule on Easter Monday or Good Friday.

Usage

recur_on_easter(x, offset = 0L)

Value

An updated rrule.

Arguments

x

[rrule]

A recurrence rule.

offset

[integer(1)]

An offset in terms of a number of days on either side of Easter to recur on. This offset must still fall within the same year, otherwise the date will be silently ignored.

Examples

on_easter <- yearly() %>% recur_on_easter()
on_easter_monday <- yearly() %>% recur_on_easter(-1)

alma_search("1999-01-01", "2001-01-01", on_easter)

rb <- runion() %>%
  add_rschedule(on_easter) %>%
  add_rschedule(on_easter_monday)

alma_search("1999-01-01", "2001-01-01", rb)


# Note that `offset` must land within the same year, otherwise the date
# is ignored
on_easter_back_93_days <- yearly() %>% recur_on_easter(-93)
on_easter_back_94_days <- yearly() %>% recur_on_easter(-94)

alma_search("1999-01-01", "2001-01-01", on_easter_back_93_days)
alma_search("1999-01-01", "2001-01-01", on_easter_back_94_days)