View difference between Paste ID: VTmyiw7U and zdUzsrxg

-#lang racket
+#lang racket
-
+
-(require rackunit)
+(require rackunit)
-
+
-; A fixed point of f is x such that f(x) = x.
+; A fixed point of f is x such that f(x) = x.
-; We need to develop means to get a fixed point of f.
+; We need to develop means to get a fixed point of f.
-
+
-;; Curry's Paradoxical Combinator of Y
+;; Curry's Paradoxical Combinator of Y
-(define (Y f)
+(define (Y f)
-  ((λ (r) (f (delay r r)))
+  ((λ (r) (f (delay r r)))
-   (λ (r) (f (delay r r)))))
+   (λ (r) (f (delay r r)))))
-
+
-; (Y F) = (F (F (... (Y F))))
+; (Y F) = (F (F (... (Y F))))
-; Y produces the fixed point of F
+; Y produces the fixed point of F
-
+
-;; Recursive exponentiation via Y-combinator
+;; Recursive exponentiation via Y-combinator
-(define (pow r)
+(define (pow r)
-  (λ (x n)
+  (λ (x n)
-    (define next-call ((force r) (force r)))
+    (define next-call ((force r) (force r)))
-    (cond ((= n 0) 1)
+    (cond ((= n 0) 1)
-          (else (* x (next-call x (sub1 n)))))))
+          (else (* x (next-call x (sub1 n)))))))
-
+
-;; Base to the power of exponent
+;; Base to the power of exponent
-(define (power base exponent)
+(define (power base exponent)
-  ((Y pow) base exponent))
+  ((Y pow) base exponent))
-
+
-;; Tests
+;; Tests
-(check-equal? (power 0 99) 0)
+(check-equal? (power 0 99) 0)
-(check-equal? (power 1 99) 1)
+(check-equal? (power 1 99) 1)
-(check-equal? (power 2 4) 16)
+(check-equal? (power 2 4) 16)
-(check-equal? (power 3 3) 27)
+(check-equal? (power 3 3) 27)
 (check-equal? (power 10 5) 100000)