Hello Haskell-beginners, I'm trying to work through the "Write Yourself a Scheme in 48 Hours" tutorial. One of the first exercises calls for writing code to sum up arguments on command line and display the sum. After a few tries, this worked for me: module Main where import System.Environment main :: IO () main = do args <- getArgs putStrLn ("Hello, " ++ show (sumIt args)) where sumIt x = sum $ map read x However, I have two basic questions: 1. I initially tried putStrLn("Hello, " ++ show $ sumIt args), but that didn't compile. Why not? If I wrap (show $ sumIt args) in parens, it works, but should I have to, if I didn't have to in the original code above? 2. I initially tried where sumIt = sum $ map read (the "point-free" style, I believe it's called?) but that didn't compile. Why not? A friend suggested where sumIt = sum . map read and that does work; I guess my real problem, then, is that I don't really understand the difference between the two and why the former doesn't work. Thanks in advance, Anatoly. -- Anatoly Vorobey, avorobey@gmail.com http://avva.livejournal.com (Russian) http://www.lovestwell.org (English)