# Pastebin 3flz7xOm
normalizeMessage :: String -> String
normalizeMessage = foldr f ""
    where f c s
            | isUpper c = ['*', toLower c] <> s
            | otherwise = c:s

normalizeMessage' :: String -> String
normalizeMessage' = foldMap f
  where f c
          | isUpper c = ['*', toLower c]
          | otherwise = [c]