Re: [Haskell-cafe] do you have to use fix with forkio?

5 Mar 2009

      On Thu, 2009-03-05 at 15:36 -0800, Daryoush Mehrtash wrote:
...
In this chat server implementation
http://www.haskell.org/haskellwiki/Implement_a_chat_server
forkIO is used with fix as in:
reader <- forkIO $ fix $ \loop -> do
(nr', line) <- readChan chan'
        when (nr /= nr') $ hPutStrLn hdl line
loop
Do you have to use fix?  Or is there a way to write this with a "let"?
You can certainly use let:

  reader <- forkIO $ let loop = do
      (nr', line) <- readChan chan'
      when (nr /= nr') $ hPutStrLn hdl line
      loop
    in loop

But the version with fix is clearer (at least to people who have fix in
their vocabulary) and arguably better style.

jcc

Re: [Haskell-cafe] do you have to use fix with forkio?

Jonathan Cast