That’s a good point. I can think of cases this would be an issue but I can’t come up with anything concrete. Do you have any? Shall we explore this a bit further?
Here is a slightly more complete proposal. Imagine you have a data-structure called %WeekDay{}. It has fields such as year, week, and day of week. It also has a “week_calendar” that knows how to convert it to iso days so you can convert it back to a Date or even a DateTime with timezone (you can embed timezones on the Weekday data structure if you want to or even have NaiveWeekDay without tz and WeekDay with tz).
Does this make your life better or worse? I guess though what you are implementing here is exactly a Date*, except you are using the month as week and the day as day of week. Although it may still be worth exploring if it makes computations easier or harder.
They all represent the same point in time but they are different representations. In your case, they are the same representation. So I guess my point here is that it is weird to change calendars when they have the exact same underlying representation.
