Initial data commit

Task/Ackermann-function/TXR/ackermann-function.txr

@@ -0,0 +1,22 @@
+(defmacro defmemofun (name (. args) . body)
+  (let ((hash (gensym "hash-"))
+        (argl (gensym "args-"))
+        (hent (gensym "hent-"))
+        (uniq (copy-str "uniq")))
+    ^(let ((,hash (hash :equal-based)))
+       (defun ,name (,*args)
+         (let* ((,argl (list ,*args))
+                (,hent (inhash ,hash ,argl ,uniq)))
+           (if (eq (cdr ,hent) ,uniq)
+             (set (cdr ,hent) (block ,name (progn ,*body)))
+             (cdr ,hent)))))))
+
+(defmemofun ack (m n)
+  (cond
+    ((= m 0) (+ n 1))
+    ((= n 0) (ack (- m 1) 1))
+    (t (ack (- m 1) (ack m (- n 1))))))
+
+(each ((i (range 0 3)))
+  (each ((j (range 0 4)))
+    (format t "ack(~a, ~a) = ~a\n" i j (ack i j))))