def tz.day.index

bend-kit-time@0.3.0.0 · time.bend:1056

import Base
import bend-kit-int@0.2.0.0/int.bend as Int

1056# The day number of a rule in year y, relative to January 1.
1057def tz.day.index(d: TzDay, +y: U32) -> U32:
1058  match d:
1059    case Julian{+n}:
1060      (n - 1 + Bool.pick(U32, Bool.and(Date.is_leap(y), U32.is_ge(n, 60)), 1, 0) : U32)
1061    case Ordinal{n}:
1062      n
1063    case MonthWeek{+month, +week, +weekday}:
1064      +first_day = (Date.weekday(Date{y, month, 1}) % 7 : U32)
1065      +day = (1 + ((weekday + 7 - first_day) % 7) + (week - 1) * 7 : U32)
1066      +last = Date.days_in_month(y, month)
1067      +actual = Bool.pick(U32, U32.is_gt(day, last), (day - 7 : U32), day)
1068      Int.I64.to_u32(Int.I64.sub(Date.to_days(Date{y, month, actual}), Date.to_days(Date{y, 1, 1})))