20 Jan
2012
20 Jan
'12
12:29 p.m.
On 20/01/12 16:31, Mikhail Arefiev wrote:
Is there a reason why there is no instance of (Enum a) => IArray UArray a (other than that it will require OverlappingInstances and/or IncoherentInstances if e. g. UArray of Bools is used in the same code)?
...
Does having such thing make any sense?
The problem is that there are Enum instances for things for which to/fromEnum doesn't make sense, such as Double, Float and Integer. Prelude> fromEnum (12345678901234567890 :: Integer) -6101065172474983726 You wouldn't want your Integers to be stored as Ints in an array. Twan