Haskell is the king of cancellation. Using asynchronous exceptions, you can cancel anything, anytime, with user -defined exception types so you know what the ca

Haskell is the king of cancellation. Using asynchronous exceptions, you can cancel anything, anytime, with user -defined exception types so you know what the cancellation reason is. Example: maybeVal <— timeout 1000000 myFunction Some people think that async exceptions are a pain because you nerd to be prepared that your code can be interrupted any time, but I think it's absolutely worth it because in all the other languages I encounter progress bars that keep running when I click the cancel button, or CLI programs that don't react to CTRL+C. In Haskell, cancellability is the default and carries no syntax overhead. This is one of the reasons why I think Haskell is currently the best language for writing IO programs.