[Haskell-cafe] self-referential data

[brian]

>From https://secure.wikimedia.org/wikipedia/en/wiki/Bencoding , I
think I should code

data BValue = BString     String
            | BInteger    Integer
            | BList       [BValue]
            | BDictionary (M.Map BString BValue)

but: Not in scope: type constructor or class `BString'

The implementations I've found just implemented BDictionary's map key
as String, but I think that's kind of wrong.