Proposal: Extensible exceptions

[Chris Kuklewicz]

Ian Lynagh wrote:
> === Library function differences
> 
> As far as the library functions are concerned, here are the main
> differences:
> 
> The old and new types for catch are:
>     Old: catch ::                IO a -> (Exception -> IO a) -> IO a
>     New: catch :: Exception e => IO a -> (e         -> IO a) -> IO a
> i.e. catch can now catch any type of exception; we don't have to force
> all the different types of extension into one fixed datatype.

Is there any sane way to allow extending or building equivalents to these for 
MonadIO?

-- 
Chris