People, is it possible to arrange a connected output and input (with something like a socket) "in a middle" of the Haskell function? Consider the example of sorting an integer list: sortInt :: [Int] -> [Int] sortInt js = let callString = "sortForeign( " ++ (show js) ++ ")" ? = outputToSocket callStr socket? -- strict order? resStr = inputFromSocket socket? :: String -- (res, _) = reads str' :: ([Int], String) in res It forms the call string for a foreign function, passes it to a Socket, the foreign system parses callString, evaluates it, and returns the string resStr for the result (inputFromSocket needs to happen later than outputToSocket). Then, reads converts it back to [Int]. Forgetting of the pure-functionality philosophy, which items in the Haskell library or in the GHC library may help? Is the C interface needed? What if there is a file instead of socket? (for this Foreign is able to apply readFile, to parse and evaluate the call). I had an experience with readFile in Haskell, but this was only the top function. Here the situation looks more complex. Thank you in advance for your explanation. ------ Sergei. mechvel@botik.ru