usage:

data A = ...

instance Bounded A where
 minBound = minBound_enumerable array_A
 maxBound = maxBound_enumerable array_A

instance Enum A where
 toEnum   = toEnum_enumerable   array_A
 fromEnum = fromEnum_enumerable table_A

-- CAF
array_A :: Array Int A
array_A = array_enumerable

-- CAF
table_A :: Map A Int
table_A = table_enumerable

-- we must pass in CAFs
-- (i.e. expressions that are top-level and unconstrained),
-- which will be shared between all calls to minBoundmaxBoundtoEnum/fromEnum.
-- TODO must we?

• -TODO template-haskell

(also see the source of Enumerate.Example)