I'm trying to learn to use the Writer Monad, but I'm having trouble with the following very simple program: import Control.Monad.Writer foo :: Writer String Int foo = tell "hello" Basically, I was trying to figure out the 'tell' function, so I want foo to return ((), "hello"). But I get this error: Couldn't match `Int' against `()' Expected type: Writer String Int Inferred type: Writer String () In the application `tell "hello"' In the definition of `foo': foo = tell "hello" What am I supposed to do? Write my own version of tell for Writer String Int? How exactly do I do this? -- View this message in context: http://www.nabble.com/writer-monad-help-tf3777133.html#a10680445 Sent from the Haskell - Haskell-Cafe mailing list archive at Nabble.com.