Re: [Haskell-cafe] windows network programming

Just starting out here so I don't know what I'm doing yet, but this one doesn't compile for me. ping.hs:19:13: parse error on input `<-' So am I doing something stupid here or is there something wrong with the code? -Tako On Fri, Jan 21, 2011 at 04:48, Michael Litchard wrote:

freenode figured this out. Pasting here for future reference.

import Control.Concurrent import Network import System.IO

main :: IO () main = withSocketsDo $ do m <- newEmptyMVar

forkIO (waitAndPong m) ping m

-- The basic server waitAndPong :: MVar () -> IO () waitAndPong m = do

socket <- listenOn (PortNumber 8000) putMVar m ()

(handle,_,_) <- accept socket hSetBuffering handle LineBuffering

incoming <- hGetLine handle putStrLn ("> " ++ incoming) hPutStrLn handle "pong"

-- The basic client ping :: MVar () -> IO () ping m = do _ <- takeMVar m handle <- connectTo "localhost" (PortNumber 8000)

hSetBuffering handle LineBuffering hPutStrLn handle "ping" incoming <- hGetLine handle putStrLn ("< " ++ incoming)

On Thu, Jan 20, 2011 at 6:17 PM, Michael Litchard wrote:

...

I tried this as an example and got the following error when running.

net.exe: connect: failed (Connection refused (WSAECONNREFUSED))

Firewall is off, running as administrator

Windows is Windows 7 Enterprise.

Advice on what to do next is appreciated

On Tue, Nov 2, 2010 at 1:24 PM, Nils Schweinsberg wrote:

...

Am 02.11.2010 19:57, schrieb Michael Litchard:

got any urls with examples?

...

Sure, see this short server-client-ping-pong application.

By the way, I noticed that you don't need withSocketsDo on windows 7, but I guess it's there for a reason for older windows versions. :)

import Control.Concurrent import Network import System.IO

main :: IO () main = withSocketsDo $ do forkIO waitAndPong ping

-- The basic server waitAndPong :: IO () waitAndPong = do socket <- listenOn (PortNumber 1234) (handle,_,_) <- accept socket hSetBuffering handle LineBuffering incoming <- hGetLine handle putStrLn ("> " ++ incoming) hPutStrLn handle "pong"

-- The basic client ping :: IO () ping = do handle <- connectTo "localhost" (PortNumber 1234) hSetBuffering handle LineBuffering hPutStrLn handle "ping" incoming <- hGetLine handle putStrLn ("< " ++ incoming)

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