Would not "liftM2 (,) [0..] [Sunday .. Saturday]" do the trick?
You mean liftM2 (,) [0..] [January .. December] ? (I chose Months in order to get a sensible example.)
Ah, yes. My mistake.
I assume that the Bounded class exists in order to stay independent from the particular type. With minBound and maxBound you do not rely on whether the counting starts on Sunday or Monday if you only want to do something for all days.
Now I see. Sure, your code can be used for any bounded type while mine is specific to Days (or Months). Well, to achieve the same with cyclic enums I would need yet another type class to get bounds which do not put any constraints on exceptions for succ and pred. That would be rather stupid, I think. Would be better with a dedicated cyclic enum class that do not have the succ and pred constraints for bounded instances.
Sure there are subtleties, like what should [Monday .. Monday] return, either: [Monday] or [Monday, Tuesday ... Sunday] but to settle for one would be ok to me.
You mean [Monday, Tuesday ... Sunday, Monday] ?
Actually not. No repetitions.
I also think that there must be a possibility to obtain an empty list.
That would be tricky. Not sure why an empty list must be obtained. /Johan