ool -> Int
boolToInt False = 0
boolToInt True  = 1

simpleParseDec :: (Eq a, Num a) => String -> Maybe a
simpleParseDec = fmap fst . listToMaybe . filter (null . snd) . readDec
simpleParseDec = fmap fst . listToMaybe . filter (null . snd) . readDec