Is month comparable? If not how to convert it to an int?


I want to use the Date library date 4.0.0
This library represents months as Time.Month values instead of integers.
I need to build a Dict that uses months as key.
It doesn’t seem to be possible with Time.Month (although the compiler error doesn’t say explicitly that the problem is that Month is not comparable, I guess this is the problem).
I’d like to know if Time.Month is comparable. If not how to convert Time.Month to Int ? The Time library says it’s possible but it doesn’t say how.


User defined Types are always not comparable, so you can not use them as key in a Dict.

You can use the function monthNumber

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Thanks. I was looking for it in the Time library since Month is defined there.

You can also use AssocList which is like a Dict but allows custom types as keys – which helps a lot to improve code IMO.

(Just don’t use it in a super performance sensitive part of your app (if you have one) and expect it to be as fast as standard Dict. I haven’t encountered a situation where it’s too slow yet, but I’ve never used for something like a game either.)

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Also don’t use AssocList if you expect normal equality to work.

What does that mean?

If you add, say, "foo" at key 1 and "bar" at key 2 into a normal Dict in both possible orders, the two results will return True when compared with ==. This is sensible, because Dict is supposed to be an unordered container, so insertion order should not matter. (But it is actually a special case in the compiler which will turn both Dicts into sorted lists and compare those instead.) If you do the same for an AssocList the two results will return False instead.

I see, thanks! Didn’t know about that.

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