How can I handle errors in asynchronous Haskell code?

How can I handle errors in asynchronous Haskell code?

In Haskell, you can use the Control.Exception module to handle errors in asynchronous code. You can wrap your asynchronous actions in try or catch to manage exceptions.

Can you give me an example of using try with async operations?

Sure! Here's a simple example:

import Control.Exception (try, SomeException)
import Control.Concurrent.Async (async, wait)

main :: IO () {
    result <- try (async someAsyncFunction) :: IO (Either SomeException ResultType)
    case result of
        Left ex -> putStrLn $ "Caught an exception: " ++ show ex
        Right val -> putStrLn $ "Result: " ++ show val
}

What about using catch instead of try?

You can use catch to handle exceptions directly within the asynchronous function. Here's an example:

import Control.Exception (catch, SomeException)
import Control.Concurrent.Async (async, wait)

someAsyncFunction :: IO ResultType
someAsyncFunction = do
    -- Your async code here
    `catch` handleError

handleError :: SomeException -> IO ResultType
handleError ex = do
    putStrLn $ "Error occurred: " ++ show ex
    return defaultValue