`orca.cron`

Cron expressions, and when they next fire in a time zone.

var c = CronExpr.parse("0 3 2 * *")          # 03:00 on the 2nd
var t = c.next_fire(now(), Zone.load("America/New_York"))

Five fields: minute (0-59), hour (0-23), day of month (1-31), month (1-12 or jan-dec) and day of week (0-7 or sun-sat, 0 and 7 both Sunday). A field is a list of *, a, a-b, each with an optional /step (a/step runs from a to the field's end). @yearly, @annually, @monthly, @weekly, @daily, @midnight and @hourly stand for the usual expressions.

As in Vixie cron, when both the day of month and the day of week are restricted (neither starts with *), a day matches if either does.

Times are matched on the zone's wall clock. A time that a spring-forward skips fires at the first moment after the gap, and a time that a fall-back repeats fires once, at its first occurrence, as Vixie cron and systemd timers do. An expression that can never match, such as 0 0 30 2 *, is refused when it's parsed.

Structs

`CronExpr`

struct CronExpr

A parsed cron expression.

Implements Copyable, Movable, Writable

Fields: text: String; minutes: UInt64; hours: UInt64; days: UInt64; months: UInt64; weekdays: UInt64; any_day: Bool: The day-of-month field starts with *.; any_weekday: Bool: The day-of-week field starts with *.

`init`

def __init__(out self, text: String)

`parse`

def parse(text: StringSpan) -> Self

`matches_day`

def matches_day(self, c: Civil) -> Bool

`next_fire`

def next_fire(self, after: Int64, zone: Zone) -> Int64

The first time after after (seconds since the epoch) that the expression fires on zone's wall clock.

`write_to`

def write_to(self, mut writer: T)