[Haskell-cafe] Alternative IO

As a joke, I wrote an instance of Alternative for IO actions: {-# LANGUAGE ScopedTypeVariables #-} module Main where import Control.Applicative import Control.Exception instance Alternative IO where empty = undefined x <|> y = handle (\ (_ :: SomeException) -> y) x This would allow to write IO code which failsafes to a value if the previous computation failed, i.e.: *Main Control.Applicative> undefined <|> print "Hello" "Hello" *Main Control.Applicative> print "Hello" <|> undefined "Hello" It seems a neat way to catch exception in some scenarios. What do you think? Why is not Alternative IO defined in Control.Applicative? Thanks, Cristiano