adding about functions

koans/about_functions.clj

@@ -0,0 +1,21 @@
+(defn count-items [& items]
+  (count items))
+
+(meditations
+  "Functions are often defined before they are used"
+  (= __ (count-items :a :b :c :d))
+
+  "But they can also be defined inline"
+  (= __ ((fn [n] (Math/pow n 10)) 2))
+
+  "Or using even shorter syntax"
+  (= __ (#(Math/pow % 10)))
+
+  "Functions can beget others"
+  (= __ (((fn []
+            (fn [a b] (+ a b))))
+          4 5))
+
+  "Higher-order functions take function arguments"
+  (= 25 ((fn [f] (f 5))
+          (fn [n] (__ __ __)))))

koans/path_to_enlightenment.clj

@@ -16,4 +16,5 @@
 (load "about_vectors")
 (load "about_sets")
 (load "about_maps")
+(load "about_functions")
 (println "You have acheived clojure enlightenment. Namaste.")