One work-around is to define something like:
instance Ord e => Ord (Set e) where
compare a b = compare (setToList a) (setToList b)
should work fine and shouldn't be too inefficient (I asked a similar
question a while back about FiniteMap, upon which Set is built).
- Hal
--
Hal Daume III
"Computer science is no more about computers | [EMAIL PROTECTED]
than astronomy is about telescopes." -Dijkstra | www.isi.edu/~hdaume
On Fri, 15 Nov 2002, Mark T.B. Carroll wrote:
> Am I right in thinking that sets of sets don't really work with GHC's
> Data.Set because "Set a" things aren't instances of Ord? How should I do
> sets of sets with it?
>
> (e.g. Set.mkSet [Set.unitSet 1] gives "No instance for (Ord (Set a))")
>
> -- Mark
>
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