apl: membership ∊, dyadic ⍳, without ~ (dyadic); 94/94 tests

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

lib/apl/runtime.sx

@@ -753,3 +753,45 @@
             ((inner-shape (rest shape))
               (inner-size (reduce * 1 (rest shape))))
             (make-array inner-shape (take ravel inner-size))))))))
+
+(define
+  apl-member
+  (fn
+    (a b)
+    (let
+      ((a-ravel (if (scalar? a) (list (disclose a)) (get a :ravel)))
+        (b-ravel (if (scalar? b) (list (disclose b)) (get b :ravel)))
+        (a-shape (get a :shape)))
+      (make-array
+        a-shape
+        (map (fn (x) (if (index-of b-ravel x) 1 0)) a-ravel)))))
+
+(define
+  apl-index-of
+  (fn
+    (v w)
+    (let
+      ((v-ravel (if (scalar? v) (list (disclose v)) (get v :ravel)))
+        (w-ravel (if (scalar? w) (list (disclose w)) (get w :ravel)))
+        (w-shape (get w :shape))
+        (n (len (if (scalar? v) (list (disclose v)) (get v :ravel)))))
+      (make-array
+        w-shape
+        (map
+          (fn
+            (x)
+            (let
+              ((i (index-of v-ravel x)))
+              (if i (+ i apl-io) (+ n apl-io))))
+          w-ravel)))))
+
+(define
+  apl-without
+  (fn
+    (a b)
+    (let
+      ((a-ravel (if (scalar? a) (list (disclose a)) (get a :ravel)))
+        (b-ravel (if (scalar? b) (list (disclose b)) (get b :ravel))))
+      (let
+        ((result (filter (fn (x) (not (index-of b-ravel x))) a-ravel)))
+        (make-array (list (len result)) result)))))