apl: power f⍣n + fixed-point f⍣≡ (+9 tests, 191/191)

lib/apl/runtime.sx

@@ -1066,3 +1066,20 @@
 (define apl-compose (fn (f g x) (f (g x))))
 
 (define apl-compose-dyadic (fn (f g x y) (f x (g y))))
+
+(define
+  apl-power
+  (fn (f n x) (reduce (fn (acc i) (f acc)) x (range 0 n))))
+
+(define
+  apl-power-fixed
+  (fn
+    (f x)
+    (let
+      ((next (f x)))
+      (if
+        (and
+          (equal? (get next :shape) (get x :shape))
+          (equal? (get next :ravel) (get x :ravel)))
+        x
+        (apl-power-fixed f next)))))