2 Even Fibonacci Numbers

0001/main.lisp

@@ -1,13 +1,13 @@
 (defun genlist (n)
   (defun impl (x lst)
     (if (> x n)
-	(reverse lst)
-	(impl (+ 1 x) (cons x lst))))
+        (reverse lst)
+        (impl (+ 1 x) (cons x lst))))
   (impl 1 '()))
 
 (let ((sum 0))
   (loop for x in (genlist 999)
-        do (if (or (equal 0 (mod x 3))
+	do (if (or (equal 0 (mod x 3))
 		   (equal 0 (mod x 5)))
 	       (setf sum (+ sum x))))
   (print sum))

0002/main.lisp

@@ -0,0 +1,19 @@
+(defun new-next-fibo-generator ()
+  (let ((x0 0)
+	(x1 1))
+    (lambda ()
+      (let ((next (+ x0 x1)))
+	(setf x0 x1)
+	(setf x1 next)
+	next))))
+
+(defvar *uplimit* 4000000)
+
+(let ((next-fibo (new-next-fibo-generator))
+      (sum 0))
+  (do ((x (funcall next-fibo) (funcall next-fibo)))
+      ((> x *uplimit*) sum)
+    (setf sum (if (evenp x)
+		  (+ sum x)
+		  sum)))
+  (format t "~&~S" sum))