add let* and letrec*

2013-11-14 13:17:54 +09:00
parent bc61cc4665
commit 0462aebce0
2 changed files with 59 additions and 13 deletions
@@ -15,3 +15,37 @@
  (print (my-odd? 42))
  (print '(my-even? 57))
  (print (my-even? 57)))
+
+(print 70)
+(print
+ (let ((x 2)
+       (y 3))
+   (let* ((x 7)
+	  (z (+ x y)))
+     (* z x))))
+
+(print 5)
+(print
+ (letrec ((p
+	   (lambda (x)
+	     (+ 1 (q (- x 1)))))
+	  (q
+	   (lambda (y)
+	     (if (zero? y)
+		 0
+		 (+ 1 (p (- y 1))))))
+	  (x (p 5))
+	  (y x))
+   y))
+
+;; (let ()
+;;   (define my-odd? (lambda (n)
+;; 		    (if (= n 0)
+;; 			#t
+;; 			(not (my-even? (- n 1))))))
+;;   (define my-even? (lambda (n)
+;; 		     (if (= n 0)
+;; 			 #t
+;; 			 (not (my-odd? (- n 1))))))
+;;   (print (my-odd? 42))
+;;   (print (my-even? 57)))