FYI: universe

[phadej]

There is http://hackage.haskell.org/package/universe and http://hackage.haskell.org/package/enumerable. How this package is different (I.e. better), taken into account dmwit/universe#23 and other further development opportunities

[AshleyYakeley]

AFAICT, those packages deal with Countable and Finite classes, but not Searchable.

For example, because we have Searchable (Integer -> Bool), even though we don't have Finite (Integer -> Bool), we can provide forevery :: ((Integer -> Bool) -> Bool) -> Bool as well as an extensional Eq ((Integer -> Bool) -> Integer).