On Wed, Jun 03, 2020 at 03:04:59PM +0800, ☂Josh Chia (謝任中) wrote: > I want to putStrLn each element and then print the length of str [...] > doit :: Stream (Of String) IO () -> IO () > doit str = > do > SP.mapM_ putStrLn str > SP.length_ str >>= print Isn't it SP.length_ (SP.mapM_ putStrLn str) >>= print