added some of chatper 2, section 1

src/sicp/chapter1/section2.clj

@@ -102,12 +102,23 @@
 
 
 ;; Exercise 1.16
+;; Herwig's implementation
 
 (letfn [(square [x] (* x x))]
   (defn fast-expt' [b n]
-    (loop [n n a 1]
+    (loop [a 1 b b n n]
       (cond (zero? n) a
-            (even? n) (recur (/ n 2)
-                             (* b (square a)))
-            :else (recur (dec n)
-                         (* b a))))))
+            (even? n) (recur a
+                             (square b)
+                             (/ n 2))
+            :else (recur (* a b)
+                         b
+                         (dec n))))))
+
+;; Exercise 1.17
+
+(letfn [(double [x] (* x 2))
+        (halve  [x] (/ x 2))]
+  (defn multi [a b]
+    (cond (zero? b) a
+          )))

src/sicp/chapter2/section1.clj

@@ -0,0 +1,71 @@
+(ns chatper2.section1
+  (:refer-clojure :exclude (cons))
+  (:use clojure.test))
+
+;; Exercise 2.1
+
+(defn gcd [a b]
+  (if (zero? b)
+    a
+    (gcd b (rem a b))))
+
+(defn make-rat [n d]
+  (let [g (gcd n d)
+        n (/ n g)
+        d (/ d g)]
+    (if (and (pos? n) (neg? d))
+      [(* n -1) (* d -1)]
+      [n d])))
+
+
+;; Exercise 2.2
+
+(def make-segment vector)
+
+(def start-segment first)
+
+(def end-segment second)
+
+(def make-point vector)
+
+(def x-point first)
+
+(def y-point second)
+
+(defn midpoint-segment [[[x1 y1] [x2 y2]]]
+  [(/ (+ x1 x2) 2)
+   (/ (+ y1 y2) 2)])
+
+
+;; Exercise 2.3
+
+(def make-rect vector)
+
+(letfn [(width  [[[x1 _] [x2 _]]]
+                (Math/abs (- x1 x2)))
+        (height [[[_ y1] [_ y2]]]
+                (Math/abs (- y1 y2)))]
+
+  (defn rect-perimeter [hypotenuse]
+    (* 2 (+ (width  hypotenuse)
+            (height hypotenuse))))
+
+  (defn rect-area [hypotenuse]
+    (* (width  hypotenuse)
+       (height hypotenuse))))
+
+
+;; Exercise 2.4
+
+(defn cons [x y]
+  (fn [m]
+    (m x y)))
+
+(defn car [z]
+  (z (fn [p _]
+       p)))
+
+(defn cdr [z]
+  (z (fn [_ q]
+        q)))
+