Clojure Koans Walkthrough

1. Introduction
2. Lists
3. Vectors
4. Sets
5. Maps
6. Functions
7. Conditionals
8. Higher Order Functions
9. Runtime Polymorphism
10. Lazy Sequences
11. Sequence Comprehensions
12. Creating Functions
13. Recursion
14. Destructuring
15. Refs
16. Atoms
17. Macros
18. Datatypes
19. Java Interop
20. Partition

Recommended Books

• ← Functions
• Higher Order Functions →

7. Conditionals - Koans Walkthrough

This video covers conditionals, such as: if, case and cond.

Here is the 07_conditionals.clj source code:

(defn explain-defcon-level [exercise-term]
  (case exercise-term
        :fade-out          :you-and-what-army
        :double-take       :call-me-when-its-important
        :round-house       :o-rly
        :fast-pace         :thats-pretty-bad
        :cocked-pistol     :sirens
        :say-what?))

(meditations
  "You will face many decisions"
  (= :a (if (false? (= 4 5))
          :a
          :b))

  "Some of them leave you no alternative"
  (= [] (if (> 4 3)
          []))

  "And in such a situation you may have nothing"
  (= nil (if (nil? 0)
          [:a :b :c]))

  "In others your alternative may be interesting"
  (= :glory (if (not (empty? ()))
              :doom
              :glory))

  "You may have a multitude of possible paths"
  (let [x 5]
    (= :your-road (cond (= x 6) :road-not-taken
                        (= x 7) :another-road-not-taken
                        :else :your-road)))

  "Or your fate may be sealed"
  (= 'doom (if-not (zero? 0)
          'doom
          'doom))

  "In case of emergency, sound the alarms"
  (= :sirens
     (explain-defcon-level :cocked-pistol))

  "But admit it when you don't know what to do"
  (= :say-what?
     (explain-defcon-level :yo-mama)))