Clojure State Machine

stateMachine.clj

(ns stateMachine)

(defn parse-integer [str]
    (try (Integer/parseInt str) 
         (catch NumberFormatException nfe 0)))

(defn displayMenu
  "This function displays the menu and gets the user's input"
  []
  (println "Displaying the menu")
  (println "Choose your option")
  (case (parse-integer (read-line))
    1 :option1
    2 :option2
    3 :option3
    :error))

(defn programLoop
  "This fuction represents the main program loop"
  []
  (letfn [
          (startState []
                      #(getUserChoice))
          (getUserChoice []
                         (case (displayMenu)
                           :option1 #(option1)
                           :option2 #(option2)
                           :option3 #(option3)
                           #(getUserChoice)))
          (option1 []
                   (println "Option 1")
                   #(startState))
          (option2 []
                   (println "Option 2")
                   #(startState))
          (option3 []
                   (println "Option 3")
                   nil)]
         (trampoline startState)))
                   
(programLoop)