What is Clojure?

• A functional lisp for the JVM
• Consistent syntax
• Dynamic, strong typing
• (Almost) Everything is immutable
• Compiles to bytecode and JS (ClojureScript)

Collections

• List: (1 2 false)
• Vector: ["ham biscuit" 7 (1 2 3)]
• Map: {"key" "value", 1 true}

Collections as values

• List: (1 2 false)
• Vector: ["ham biscuit" 7 (1 2 3)]
• Map: {"key" "value", 1 true}

Code is data

(println "Hello friends!")

(doseq [technology ["Vert.x" "Netty"]]
  (println technology "is the bomb."))

Java Interop

(import '[java.util.concurrent CountDownLatch TimeUnit])

(let [latch (CountDownLatch. 1)
      thread (Thread.
               (fn []
                 (println "Thread started")
                 (.countDown latch)))]
  (.start thread)
  (.await latch 10 TimeUnit/SECONDS))

Drawbacks

• Static runtime

Examples

Takeaways

Resources

• Stuart Sierra YOW! 2013: http://www.youtube.com/watch?v=Bcd3TOlYUGM
• Clojure & state: http://clojure.org/state
• mod-lang-clojure: https://github.com/vert-x/mod-lang-clojure
• lein-vertx: https://github.com/isaiah/lein-vertx
• ring-vertx-adapter: https://github.com/stream1984/ring-vertx-adapter
• This presentation: https://github.com/tobias/eclipsecon-vertx-clojure

Credits

• "please raise hand for assistance" - http://www.flickr.com/photos/coldtaxi/426162862/