Code was still buggy, it turns out (though the recursion checker caught
it). In the case of (Schedule (Monthly Nothing) AnyTime), where the last
run was on yyyy-12-31, it looped forever.
Also, the handling of (Schedule (Yearly Nothing) AnyTime) was wacky where
the last run was yyyy-12-31. It would suggest a window starting on the 3rd
for the next run (because 31 mod 28 is 3).
I think that originally I was wanted to avoid running on 01-01 if it had
just run on 12-31. But the code didn't accomplish this, and it's not
necessary anyway. This is supposed to calculate the next window meeting the
schedule, and for (Schedule (Monthly Nothing), the window starts at 01-01
and runs through 01-31. If that causes two back-to-back runs, well the next
one will not be until 02-01 at the earliest.
Also, back-to-back runs can be avoided, if desired, by using Divisible 2.
Allow AnyTime events that still have time to occur in the current day to
fall in a window covering the current day, instead of waiting until the
next day in the Recurrance.
Wow! This was hairy, but about 10x less hairy than expected actually!
A bit more recursion than I really like, since I think in theory all
of this date stuff can be calulated using some formulas I am too lazy too
look up. But this doesn't matter in practice; I asked it for
nextTime (Schedule (Divisible 100 (Yearly 7)) (SpecificTime 23 59) (MinutesDuration 10)) Nothing
.. and it calculated (NextTimeExactly 2100-01-07 23:59:00) in milliseconds.
Rather similar to crontab, although with a different format.
But with less emphasis on per-minute scheduling.
Also, supports weekly events, which cron makes too hard.
Also, has a duration field.
