I wrote this function as I am just learning Haskell. What it does is it generates a list of all rational numbers between 0 and 1, but I only have it show the first 20. rationals n :: Integer -> String rationals n = (putStr . unlines . map show) (take n (nub [x % y | y <- [1..], x <- [1..y], x < y])) Now my problem is the type declaration, the first line. I get the error "Invalid type signature". I googled this error and I was not able to find out why it is giving it to me. I have also tried: rationals n :: Integer -> [Ratio] but it gives me the same error. Please someone point me in the right direction. Thanks. -- View this message in context: http://www.nabble.com/Function-Returning-Type--tp23658819p23658819.html Sent from the Haskell - Haskell-Cafe mailing list archive at Nabble.com.