Re: Sets of IOErrors?

[George Russell]

Fergus Henderson wrote:
[snip]
> So why limit expressiveness by providing only the former?
Why indeed?  You are right.  I hadn't realised that
   a -> IO (Maybe a)
would still suffer from non-determinism.
(Because if you have 
   x = error "foo" + _|_
   it may cause a return of Nothing or else no return at all.)
So there is no reason for not going the whole way and letting
the caller inspect the contents of the exception.