Add 1.5 to 1.8 using clojure

Author: anabastos

1.1-TheElementsOfProgramming/ex-1.5/anabastos.clj

@@ -0,0 +1,10 @@
+(defn p [] p)
+
+(defn test 
+    [x y]
+    (if (> x 0) 0 y))
+
+(test 0 (p))
+
+; The expression (test 0 (p)) will end in a infinite loop if the programming language evaluates in applicative-order 
+; In normal order evaluation the expression is evaluated outside in, terminating the execution.

1.1-TheElementsOfProgramming/ex-1.6/anabastos.clj

@@ -0,0 +1,32 @@
+(defn new-if 
+    [predicate then-clause else-clause]
+    (cond predicate then-clause
+        :else else-clause))
+
+(defn average 
+  [x y]
+  (/ (+ x y) 2))
+
+(defn improve 
+  [guess x]
+  (average guess (/ x guess)))
+
+(defn square [x] (* x x))
+
+(defn abs [n] (max n (- n)))
+
+(defn good-enough? 
+  [guess x]
+  (< (abs (- (square guess) x)) 0.001))
+
+(defn sqrt [x]
+  (sqrt-iter 1.0 x))
+
+(defn sqrt-iter 
+    [guess x]
+    (new-if (good-enough? guess x)
+          guess
+          (sqrt-iter (improve guess x) x)))
+
+; clojure uses applicative-order evaluation so new-if will get evaluated
+; substituting all arguments first so sqrt-inter will end up in a infinite loop

1.1-TheElementsOfProgramming/ex-1.7/anabastos.clj

@@ -0,0 +1,29 @@
+(defn new-if 
+    [predicate then-clause else-clause]
+    (cond predicate then-clause
+        :else else-clause))
+
+(defn average 
+  [x y]
+  (/ (+ x y) 2))
+
+(defn improve 
+  [guess x]
+  (average guess (/ x guess)))
+
+(defn square [x] (* x x))
+
+(defn abs [n] (max n (- n)))
+
+(defn good-enough? 
+  [guess x]
+  (< (abs (- (square guess) x)) 0.001))
+
+(defn sqrt [x]
+  (sqrt-iter 1.0 x))
+
+(defn sqrt-iter 
+    [guess previous-guess x]
+    (new-if (good-enough? guess previous-guess)
+          guess
+          (sqrt-iter (improve guess x) guess x)))

1.1-TheElementsOfProgramming/ex-1.8/anabastos.clj

@@ -0,0 +1,20 @@
+(defn square [x] (* x x))
+(defn cube [x] (* x x x))
+(defn abs [n] (max n (- n)))
+
+(defn improve [guess x]
+  (/ (+ (/ x (square guess))
+        (* 2 guess) )
+     3))
+
+(defn good-enough? [guess x]
+  (< (abs (- (cube guess) x)) 0.001))
+
+(defn cbrt-iter [guess x]
+  (if (good-enough? guess x)
+    guess
+    (cbrt-iter (improve guess x) x)))
+
+(defn cbrt [x]
+  (cbrt-iter 1.0 x))
+