I am learning haskell and i need some advice about writing functional-style code.

Give the following code below, my question is - how do i setup a dependency of User on Common?

Obviously what i have there is wrong, because a change in common (i know it's actually immutable) is not reflected in the version captured by User. I understand why my current approach has not a chance a of working, I am using it to, hopefully, illustrate my goal.

Thanks for any suggestions

> data Common = Common {
> cName :: String,
> cValue :: Int
> } deriving (Show)
> data User = User {
> uCommon :: Common
> } deriving (Show)
> makeWorld = (commons, users)
> where
> commons = [Common "A" 1, Common "B" 2]
> users = [User (head commons)]
>
> main = do
> let world = makeWorld
> putStrLn (show world)