DateTime::React

A module for Raku that makes it incredibly easy to be alerted when clock rollovers occur (e.g. when the minute or hour ticks up).

Using it is very simple:

use DateTime::React;

react {
    whenever minute-shifts() {
        say "We've gone from ??:??:59 to ??:??:00!";
    }
    whenever hour-shifts() {
        say "We've gone from ??:59:59 to to ??:00:00!";
    }
    whenever day-shifts() {
        say "We've gone from 23:59:59 to to 00:00:00!";
    }
    whenever timezone-shifts() -> $shift {
        say "The offset in {$shift.timezone} is now {$shift.new-offset}!";
    }
}

Each supply emits a meta event of type DateTimeEventish. It provides three values:

• time: the time the event was scheduled

• next-at: when the next event will occur

• type: the type of event (any of minute, hour, day, month, year, timezone)

Currently, only timezone-shifts() provides additional metadata:

• olson-id: the Olson (or IANA) identifier for the timezone

• timezone: an alias of olson-id

• old-offset: the former GMT offset (e.g. -5h for America/New_York for spring switch over)

• new-offset: the now current GMT offset (e.g. -4h for America/New_York for spring switch over)

When using timezone-shifts(), this module will (currently) automatically adjust the $*TZ value for you so that new DateTime objects are generated with the correct offset. Be mindful that DateTime itself is not timezone aware, so creating historical/future dates will always use the current $*TZ value. If that is needed, you should look at the DateTime::Timezones module which does that for you.

The $*TZ adjusting feature may be moved into a different module down the road but the behavior will be maintained (at the cost of an additional dependency for this one).

Version history

• v0.1.0

  • Initial release

Copyright / License

Copyright © 2022 Matthew Stephen Stuckwisch. Licensed under the Artistic License 2.0