unifying introductory functions a bit

ideaboard.txt

@@ -1,16 +1,10 @@
 Tuples - syntax
 Pattern Matching
-Functions returning functions
-Functions taking functions
-if expressions
-for comprehensions
 immutability/side effects
 state identity lifetime
-map, reduce, filter
-lists / cons
 memoization
 lazy sequences
 recursion
-recrusive list processing
+recursive list processing
 currying / pfa
 reflection

src/koans/about_conditionals.clj

@@ -1,10 +1,16 @@
 (meditations
-  "Your will face many decisions"
+  "You will face many decisions"
   (= __ (if (false? (= 4 5)) :a :b))
 
   "Some of them leave you no alternative"
   (= __ (if (> 4 3) []))
 
   "And in such a case you may have nothing"
-  (= nil (if (nil? __) [:a :b :c])))
+  (= nil (if (nil? __) [:a :b :c]))
+
+  "In others your alternative may be interesting"
+  (= :glory (if (not (empty? ())) :doom __))
+
+  "Or your fate may be sealed"
+  (= __ (if-not (zero? __) 'doom 'doom)))
 

src/koans/about_functions.clj

@@ -1,19 +1,19 @@
-(defn count-items [& items]
-  (count items))
+(defn raise-to-the-tenth-power [n]
+  (Math/pow n 10))
 
 (meditations
   "Functions are often defined before they are used"
-  (= __ (count-items :a :b :c :d))
+  (= __ (raise-to-the-tenth-power 2))
 
   "But they can also be defined inline"
-  (= __ ((fn [n] (Math/pow n 10)) 2))
+  (= __ ((fn [n] (Math/pow n __)) 2))
 
   "Or using even shorter syntax"
-  (= __ (#(Math/pow % 10)))
+  (= __ (#(Math/pow % 10) __))
 
-  "Functions can beget others"
+  "One function can beget another"
   (= __ (((fn []
-            (fn [a b] (+ a b))))
+            (fn [a b] __ a b)))
           4 5))
 
   "Higher-order functions take function arguments"