[Haskell-cafe] Re: Why is Day and Month bounded?
lemming at henning-thielemann.de
Fri Jul 14 05:24:13 EDT 2006
On Fri, 14 Jul 2006, Johan Holmquist wrote:
> I'll answer my own post to elaborate:
> If Day (and Month) where NOT instances of Bounded, the following would
> be possible:
> [Monday .. Sunday]
> => should return [Monday, Tuesday ... Saturday, Sunday]
> => but returns 
[Monday, Tuesday ... Saturday, Sunday, Monday, Tuesday ... Saturday, Sunday] ?
Since the days are cycling, what is more natural about your result
compared to my one?
I assume the Bounded instance exists in order to allow loops like
liftM2 (,) [0..] [minBound .. (maxBound::System.Time.Month)]
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