winSSQ count noRed noBlue = do { yesRed <- [1..33] \\ noRed; yesBlue <- [1..16] \\ noBlue; bracket (openFile "ssqNum.txt" WriteMode) (hClose) (\hd1 -> pickSSQ count yesRed yesBlue hd1); return () } will report: Couldn't match expected type `IO ()' against inferred type `[()]' In a stmt of a 'do' expression: bracket (openFile "ssqNum.txt" WriteMode) (hClose) (\ hd1 -> pickSSQ count yesRed yesBlue hd1) However, the following works fine: winSSQ count noRed noBlue = do let yesRed = [1..33] \\ noRed let yesBlue = [1..16] \\ noBlue bracket (openFile "ssqNum.txt" WriteMode) (hClose) (\hd1 -> pickSSQ count yesRed yesBlue hd1) Why ? -- View this message in context: http://www.nabble.com/How-to-use-%22bracket%22-properly---tp25953522p2595352... Sent from the Haskell - Haskell-Cafe mailing list archive at Nabble.com.