Quick question: Are there plans to develop auto-complete for 'X' language, and if not, is it possible to build your own auto-complete feature for 'X' language u

Quick question: Are there plans to develop auto-complete for 'X' language, and if not, is it possible to build your own auto-complete feature for 'X' language using the plugin API? When learning a new language, and especially when learning a new library, I dearly miss auto-complete (e.g. what you get in Eclipse with Java). I'm learning Haskell, and this would be a fantastic way to get more familiar with not only the standard Prelude, but any of the other Haskell libraries.