This should not cause any working configs to stop working, because IO is an instance of MonadIO, and because complete configs will pin down the type of the call to IO. Note that XMonad.Config.Arossato is not a complete config, and so it needed some tweaks; with a main function, this should not be a problem.
XMonad.Prompt.Input is a new module which provides a framework for
prompting the user for input and passing it along to some other action,
useful for building actions which require user input.
XMonad.Prompt.Email is a simple example of the use of XMonad.Prompt.Input,
which prompts the user for a recipient, subject, and body, and sends
a one-line email.
I also made a small refactoring to XMonad.Prompt in order to support
XMonad.Prompt.Input.
