fix ackermann

Author: xieyuheng

examples/ackermann.lisp

@@ -7,7 +7,11 @@
     (add1 n)
     (if (zero? n)
       (ackermann (sub1 m) one)
-      (ackermann (sub1 m) (ackermann m n)))))
+      (ackermann (sub1 m) (ackermann m (sub1 n))))))
+
+;; TODO fail:
+
+;; ackermann
 
 (define ackermann-wrap
   (lambda (ackermann)
@@ -16,7 +20,7 @@
         (add1 n)
         (if (zero? n)
           (ackermann (sub1 m) one)
-          (ackermann (sub1 m) (ackermann m n)))))))
+          (ackermann (sub1 m) (ackermann m (sub1 n))))))))
 
 (assert-equal ackermann ackermann)
 (assert-equal ackermann (ackermann-wrap ackermann))

examples/ackermann.test.lisp

@@ -1,19 +1,16 @@
-(import zero one two three "nat-church.lisp")
+(import zero one two three four five "nat-church.lisp")
 (import ackermann ackermann-wrap "ackermann.lisp")
 
 (assert-equal (ackermann zero zero) one)
 (assert-equal (ackermann one zero) two)
 (assert-equal (ackermann zero one) two)
+(assert-equal (ackermann one one) three)
+(assert-equal (ackermann one two) four)
+(assert-equal (ackermann two one) five)
 
 ackermann-wrap
 
 ;; TODO fail:
 
 ;; ackermann
 ;; (ackermann-wrap ackermann)
-
-;; TODO fail:
-
-;; (ackermann one one)
-;; (ackermann one two)
-;; (ackermann two one)

examples/ackermann.test.lisp.out

@@ -1 +1 @@
-(lambda (ackermann m n) (m (lambda (t f) t) (lambda (x t f) f) (lambda (base step) (step (n base step))) (n (lambda (t f) t) (lambda (x t f) f) (ackermann (m (lambda (f) (f (lambda (base step) base) (lambda (base step) base))) (lambda (x f) (f (x (lambda (car cdr) cdr)) (lambda (base step) (step (x (lambda (car cdr) cdr) base step))))) (lambda (car cdr) car)) (lambda (base step) (step base))) (ackermann (m (lambda (f) (f (lambda (base step) base) (lambda (base step) base))) (lambda (x f) (f (x (lambda (car cdr) cdr)) (lambda (base step) (step (x (lambda (car cdr) cdr) base step))))) (lambda (car cdr) car)) (ackermann m n)))))
+(lambda (ackermann m n) (m (lambda (t f) t) (lambda (x t f) f) (lambda (base step) (step (n base step))) (n (lambda (t f) t) (lambda (x t f) f) (ackermann (m (lambda (f) (f (lambda (base step) base) (lambda (base step) base))) (lambda (x f) (f (x (lambda (car cdr) cdr)) (lambda (base step) (step (x (lambda (car cdr) cdr) base step))))) (lambda (car cdr) car)) (lambda (base step) (step base))) (ackermann (m (lambda (f) (f (lambda (base step) base) (lambda (base step) base))) (lambda (x f) (f (x (lambda (car cdr) cdr)) (lambda (base step) (step (x (lambda (car cdr) cdr) base step))))) (lambda (car cdr) car)) (ackermann m (n (lambda (f) (f (lambda (base step) base) (lambda (base step) base))) (lambda (x f) (f (x (lambda (car cdr) cdr)) (lambda (base step) (step (x (lambda (car cdr) cdr) base step))))) (lambda (car cdr) car)))))))