solution to 2.27

diff --git a/src/sicp/ex2_27.clj b/src/sicp/ex2_27.clj
new file mode 100644 (file)
index 0000000..957ec2f
--- /dev/null
+++ b/src/sicp/ex2_27.clj
@@ -0,0 +1,16 @@
+(ns sicp.ex2_27
+  (:refer-clojure :exclude (reverse))
+  (:use [clojure.test]))
+
+(def x (list (list 1 2) (list 3 4)))
+
+(defn deep-reverse [lst]
+  (cond (not (seq? lst)) lst
+       (empty? lst) nil
+       :else (cons (deep-reverse (last lst)) (deep-reverse (butlast lst)))))
+
+(deftest test-simple-list
+  (are [x y] [= x y]
+       (deep-reverse '(1 2 3 4))     '(4 3 2 1)
+       (deep-reverse '((1 2) 3 4))   '(4 3 (2 1))
+       (deep-reverse '((1 2) (3 4))) '((4 3) (2 1))))