RosettaCodeData/Task/Ackermann-function/ZED/ackermann-function.zed

("ackermann") m n
0 3
(zero?) m
(add1) n

("ackermann") m n
2 0
(and) (positive?) m (zero?) n
("ackermann") (sub1) m 1

("ackermann") m n
2 3
(and) (positive?) m (positive?) n
("ackermann") (sub1) m ("ackermann") m (sub1) n