Clojure Dynamic Binding

Question

I realize the following is a bad idea for many reasons. I also realize that given I have a stackoverflow rep of 23, it\'s nature to assume that I\'m a newb learning to progr

Answer 1

If you really want to make animal types talk idiomatically, use Clojure Protocols:

(defprotocol ISpeak
  (speak [animal] "make the type say it's thing"))

(deftype Dog []
  ISpeak
  (speak [this] "Woof!"))

(deftype Cat []
  ISpeak
  (speak [_] "Meow!!")) ;;you can "drop" the item if not used using _

(def a-dog (Dog.))
(speak a-dog)
;;=>"Woof!"

(def a-cat (Cat.))
(speak a-cat)
;;=>"Meow!!"

Please note you can extend any type (class) with the speak method.

(extend java.util.Random
  ISpeak
  {:speak (fn [_] "I'm throwing dices at you!")})

(speak (java.util.Random.))
;;=>"I'm throwing dices at you!"

The syntax is a bit different for Java classes, please see the Protocols documentation for more information.