I'm reading "Learn You a Haskell for Great Good!", chapter 9, "Input and Output" http://learnyouahaskell.com/input-and-output. IO actions are given liberal coverage throughout the chapter, however it is never mentioned whether the value-extractor syntax (<-) has a type or not. main = do x <- getLine putStrLn $ reverse x In this little program, getLine has type "IO String" and x has type "String". This implies to me that (<-) has type "IO a -> a". However, GHCI chokes on ":t (<-)" and Hoogle says it's just a syntactic element http://www.haskell.org/haskellwiki/Keywords#.3C-. I guess I don't have a specific question, but I was kind of expecting it to be a function with a type because everything seems to be a function with a type in Haskell... Thanks for listening!