pathToContents :: (MonadIO m) => FilePath -> Producer m FilePath
pathToContents dir = do
  exists <- liftIO $ doesDirectoryExist dir
  when exists $ do
    contents <- liftIO $ getDirectoryContents dir
    CL.sourceList contents
pathToContents :: (MonadIO m) => FilePath -> Producer m FilePath
pathToContents dir = do
  exists <- liftIO $ doesDirectoryExist dir
  when exists $ do
    contents <- liftIO $ getDirectoryContents dir
    CL.sourceList contents
pathToContents dir = do
  exists <- liftIO $ doesDirectoryExist dir
  when exists $ do
    contents <- liftIO $ getDirectoryContents dir
    CL.sourceList contents