On Mon, Jul 11, 2011 at 12:27 PM, Michael Orlitzky
How do people use this stuff? The README is empty, there's no documentation, and none of the functions are commented. I'm forced to conclude that there are people capable of looking at this,
createPoolCheckAlive :: MonadControlIO m => IO a -> (a -> IO ()) -> Int -> (Pool a -> m b) -> (a -> IO Bool) -> m b
and knowing immediately what it does.
Yes, there's a documentation problem. But you can guess by the types =). IO a: opens a new resource a. a -> IO (): disposes the given resource. Int: maximum number of open resources. Pool a -> m b: the action you want to execute; after it executes, the pool is destroyed. a -> IO Bool: check if the resource is still alive. m b: the result of running your given action with a new pool. The key to understanding all of this is looking backwards from the result. 1) The result is m b. Where did this come from? 2) Well, there's a 'Pool a -> m b'. So it runs the action for me. So this is like a 'withFile :: FilePath -> (Handle -> IO a) -> IO a' function. 3) So if it is a 'Pool a', then the resource is of type 'a'. 4) The only function returning 'a' is 'IO a', so this creates the resource. 5) By the same reason, 'a -> IO ()' disposes it. 6) 'a -> IO Bool' is confusing, but there's a doc for that. 7) 'Int' is also confusing, but since this is a pool, this must be the maximum number of open resources. HTH, -- Felipe.