Last Updated: February 25, 2016

Haskell Async lib

I was trying to create a thread and wait in main thread, but it was a little bit complex ( https://gist.github.com/3469872 ): had to create an MVar or Chan to know when thread is done.

Here's better way using Control.Concurrent.Async

import Control.Concurrent
import Control.Concurrent.Async
import System.Random

delayedOutput :: String -> IO ()
delayedOutput m = do
 gen <- newStdGen
 let (t, _) = randomR (1, 10) ge
 -- delay in microseconds
 threadDelay (t * 1000000)
 -- display message
 putStrLn m
 return ()

main :: IO ()
main = do
 putStrLn "Fight!"
 a <- async (delayedOutput "Finish him!")
 wait a
 return ()

#haskell