Others have provided help to answer your question but I'd like to
provide a little bit different feedback.
On Mon, Apr 13, 2009 at 8:42 AM, John Smith
Hi, a java-programmer running into trouble while trying to learn Haskell.
I try to make a hash containing hashes but can not getting a value out of the innermost hash - I keep running into type-trouble where IO and Maybe monad is getting mixed?
My attempt:
removeMaybeHash x = case x of Just ref -> ref Nothing -> HashTable.new (==) (\key -> key)
When you see yourself writing a function like this, you could write it like this instead: removeMaybeHash (Just ref) = ref removeMaybeHash Nothing = HashTable.new (==) (\key -> key) Hopefully you agree this 2 line version is more clear. You could go further of course and use the function 'maybe' from the prelude, and pass the function 'id' instead of \key -> key, but I don't want to overwhelm you. Good luck, Jason