Re: Enum instance for Ratio

[George Russell]

Marc van Dongen wrote:
> Wouldn't that make Enum depend on Ord?
> Doesn't seem to make sense if classes are
> enumerable but not comparable.
What examples are there of types for which it would be sensible to implement
Enum but not Ord?  The concept rather puzzles me.  In particular, suppose you
don't have an ordering on the pair (a,b).  How do you propose to compute
   [a..b]
?