import Text.Printf

myPutStrLn = putStrLn . (++) "log: "

-- GHC infers `myPrintf :: String -> IO ()' which is not what I want.
myPrintf = logger . printf
  where
    -- note, this is just an example. should be replaceable with any function
    -- with this typesignature
    logger :: String -> IO ()
    logger = putStrLn . (++) "log: "

main = do
  -- Instead, I would like to write
  myPrintf "test %d" (23 :: Int)
  -- but it fails with
  {-hprintf.hs:26:3:
        The function `myPrintf' is applied to two arguments,
        but its type `String -> IO ()' has only one
        In a stmt of a 'do' block: myPrintf "test %d" 23
        In the expression:
          do { myPutStrLn "hello";
               myPutStrLn $ printf "test %d" (23 :: Int);
               myPrintf "test %d" 23 }
        In an equation for `main':
            main
              = do { myPutStrLn "hello";
                     myPutStrLn $ printf "test %d" (23 :: Int);
                     myPrintf "test %d" 23 }
  -}