So what's the deal with Clojure? it's main page gives a few hints:
Clojure is a dialect of Lisp, and shares with Lisp the code-as-data philosophy and a powerful macro system. Clojure is predominantly a functional programming language, and features a rich set of immutable, persistent data structures. When mutable state is needed, Clojure offers a software transactional memory system and reactive Agent system that ensure clean, correct, multithreaded designs.
The incentive of building this plugin came after receiving news of Grails getting its own Clojure plugin. The Grails plugin has no ties to the Servlet API which makes it a perfect candidate to be ported to Griffon, however its current implementation lets you load any Clojure script and execute it. While this behavior can be replicated in Griffon using a combination of build and runtime events (like it is shown by the grojure sample application), it would be best to provide that behavior with a runtime plugin, in other words, loading Clojure scripts must wait until the addon feature is published (coming in Griffon's next point release, that is 0.2). In the meantime, you will be able to compile Clojure sources that are intended to generate a compatible Java class, those classes in turn can be called from your Java/Groovy classes. This means you are now able to write "business layer" logic in Clojure!
There are no plans in enabling members of the MVC group to be written with Clojure (or Scala or JavaFX) for now, the point of these plugins is to enable polyglot programming, harness the strengths and unique features of each language where they make sense.
Keep on Groovying!
