Editorial: Consider recombining ISO 8601 and calendar-specific operations #2948

ptomato · 2024-09-24T00:27:26Z

We have several operations such as CalendarDateAdd that basically say this:

If calendar is "iso8601", return ? DoTheISO8601Thing(parameters).
Return ? DoTheCalendarThing(calendar, parameters).

where DoTheISO8601Thing is a completely specified AO like AddISODate and DoTheCalendarThing is an implementation-dependent AO like CalendarDateAddition. This split seems unnecessary and could probably make the spec text simpler if we had just one operation instead of three. Investigate whether this is an improvement and if so, prepare a PR.

This is the only place it's called from. This refactor is part of consolidating the many calendar AOs. See: #2948

They are identical except for clamping the day value, so if we pass 1 as the day value we get the same effect. The only caller was in CalendarYearMonthFromFields. See: #2948

This is the only place it's called from. This refactor is part of consolidating the many calendar AOs. See: #2948

Move the ISO 8601 code from CalendarDateFromFields and CalendarYearMonthFromFields into CalendarDateToISO. At this point it just consists of RegulateISODate anyway. To achieve this, we also drop the requirement that CalendarDateToISO checks its return value is in the representable range, instead moving that to CalendarDateFromFields and CalendarYearMonthFromFields since it is different in both cases. See: #2948

…ceDate Move the ISO 8601 code from CalendarMonthDayFromFields into CalendarMonthDayToISOReferenceDate. See: #2948

Having two separate operations for this was already confusing just because of the names. Combine them into an ISO 8601 part and an implementation- defined part, as in CalendarDateToISO. See: #2948

Having two separate operations for this was already confusing just because of the names. Combine them into an ISO 8601 part and an implementation- defined part, as in CalendarDateAdd. In this case there was not really any specific implementation-defined description except for the already existing description. See: #2948

Move the ISO 8601-specific code from CalendarEra, CalendarYear, etc., into CalendarISOToDate. See: #2948

ISO 8601 has no extra fields, so just return an empty List from the operation instead of asserting that we don't call it with the ISO 8601 calendar. See: #2948

Move the ISO 8601 code from ISOFieldKeysToIgnore into CalendarFieldKeysToIgnore. See: #2948

Move the ISO 8601 code from ISOResolveMonth into CalendarResolveFields. See: #2948

These were all one line now, and should just call CalendarISOToDate. See: #2948

Move the ISO 8601 code from CalendarDateFromFields and CalendarYearMonthFromFields into CalendarDateToISO. At this point it just consists of RegulateISODate anyway. To achieve this, we also drop the requirement that CalendarDateToISO checks its return value is in the representable range, instead moving that to CalendarDateFromFields and CalendarYearMonthFromFields since it is different in both cases. See: #2948 Closes: #2998