Representing midnight as end of day. about time HOT 9 CLOSED

Could you be more specific about which type, etc.?

from time.

TimeOfDay would be the first type. Currently todHour has a range of 0-23. If it represented a time of day the way ISO-8601 specifies, a TimeOfDay 24 0 0 would be valid and would represent midnight at the end of the day.

I don't know what kind of consequences this change would have for other types and functions. It's very possible that it would be more appropriate to have a separate ISO-8601 library. If you think that's the case, I can go my merry way. I would at least try to make such a library as similar to time and thyme as possible.

from time.

Right now you can construct "TimeOfDay 24 0 0", and you can construct a LocalTime with it, but "makeTimeOfDayValid 24 0 0" will give Nothing.

I'd need to know what operations you'd expect to behave how.

from time.

Currently

(parseTimeM True defaultTimeLocale "%d.%m.%Y %H:%M" "01.01.2021 24:00") :: Maybe UTCTime

evaluates to Nothing

But it should be equal to

(parseTimeM True defaultTimeLocale "%d.%m.%Y %H:%M" "02.01.2021 00:00")

from time.

Hmm, representing 24:00:00 might be a requirement for ISO 8601 formatting/parsing functions.

from time.

OK, I've fixed this for ISO 8601 formatting, where it's required.

from time.

Not sure what to do about parseTimeM etc.

from time.

So the options are:

1. no change: if you want parsing to accept 24:00 then use the ISO 8601 functions
2. parsing always accepts 24:00 (changing existing behaviour)
3. a flag in TimeLocale that determines what to do

For 2 & 3, it's not clear what else should be allowed, e.g., Japanese 30-hour clock, or possibly even other fields out of range rolling over.

from time.

Going to stick with 1 for the time being.

from time.