Don Stewart wrote:
Beautiful code can be very efficient.
Indeed, as I recently the opportunity to demonstrate to my co-workers by re-implementing a script written in Perl that turned out to be just a bit too slow to be useful in practice. My version was not only one tenth the code size and about 20 times faster, it also revealed bugs in the original implementation as well as in the specification. It was fun, too. For instance, the OP's question reminded me of a little generic wrapper I wrote -- more or less for my own amusement -- during the course of this project. It outputs dots during an operation that might take a little longer to finish (a database query in my case)... just so the user doesn't get nervous ;-) And because I enjoyed it so much (and to show off) I threw in the timing measurement... module Gimmick where import Control.Concurrent import Control.Exception import System.CPUTime import System.IO tickWhileDoing :: String -> IO a -> IO a tickWhileDoing msg act = do hPutStr stderr msg >> hPutChar stderr ' ' >> hFlush stderr start_time <- getCPUTime tickerId <- forkIO ticker res <- act `finally` killThread tickerId stop_time <- getCPUTime let time_diff = realToFrac (stop_time - start_time) / 1e12 hPutStrLn stderr $ " done (took us " ++ show time_diff ++ " seconds)" return res where ticker = do hPutChar stderr '.' >> hFlush stderr threadDelay 100000 {-microsec-} ticker I think nobody in his right mind would even try to do something like that in C or Perl or whatever, at least not if it wasn't strictly a requirement and correct operation is important (the script gets executed as part of our build process and a subtle concurrency bug could lead to a wrong configuration for the target control system). In Haskell it was so easy to do that I just couldn't resist. Cheers Ben PS (completely off-topic, sorry): I've been using the collections library throughout the project & I must say it is a lot nicer to work with than the base library mumble-jumble of duplicate interfaces, qualified imports and whatnot. The only disadvantages are that the API is not yet as complete as e.g. Data.Map, and that I have to manually hide name-clashing Prelude functions in almost every module. Many thanks to Jean-Philippe Bernardy for pioneering this work.