Yes and no. As we count in days and ‘day fractions’ (my previous post was an explanation of how such a day fraction could be stored in an integer format that would be precise enough to handle leap second conversions), to calculate the difference between two dates (in days + day fractions) will not need to handle leap seconds.
A date in Elixir (%Date{}) does not have fractions, so how would you be able to use fractions in the calculation?
but note the Calendar functions should not receive structs. Otherwise we have cyclic dependencies between those which, although they are fine in Elixir, it is usually not a good practice.
How about receiving maps that would be valid structs (e.g. Date, NaiveDateTime or DateTime )?
Then all alternative calendars could have functions for to_iso and from_iso for each type Date, NaiveDateTime and DateTime that would receive/return these maps. That would make comparisons simple. You just convert to ISO and compare.
