Haskell by Example: Goroutines

original

Actually there is no goroutine in Haskell.
Instead, This example uses forkIO.
It is a common way to use concurrency in Haskell.

import Control.Monad
import Control.Concurrent

f :: String -> IO ()
f from = forM_ [0..2] (\i -> putStrLn $ from ++ ":" ++ show i)

main = do
    f "direct"
    forkIO $ f "forkIO"
    forkIO $ (\msg -> putStrLn msg) "going"

    getLine
    putStrLn "done"

$ runhaskell goroutines.hs
direct:0
direct:1
direct:2
forkIO:0
forkIOg:o1i
ngf
orkIO:2
<enter>
done

back to index