Haskell: monad stack bind with IO and []

Question

I have:

stuff :: IO [String]
doThings :: String -> IO [()]

and I want to

stuff >>= doThings

but my types are off. I want to do a lifted bind essentially but everything I try is subtly wrong.

Answer 1

With your original types, you can do:

stuff >>= mapM_ doThings

This also works if you change doThings to have type doThings :: String -> IO ()

Answer 2

If you've got lots of such functions, this is the textbook usecase of ListT :

main = runListT $ do
  string <- ListT stuff
  ListT $ doThings string