June 2018 Update

Task/Break-OO-privacy/OCaml/break-oo-privacy.ocaml

@@ -0,0 +1,33 @@
+class point x y =
+  object
+    val mutable x = x
+    val mutable y = y
+    method print = Printf.printf "(%d, %d)\n" x y
+    method dance =
+      x <- x + Random.int 3 - 1;
+      y <- y + Random.int 3 - 1
+  end
+
+type evil_point {
+  blah : int;
+  blah2 : int;
+  mutable x : int;
+  mutable y : int;
+}
+
+let evil_reset p =
+  let ep = Obj.magic p in
+  ep.x <- 0;
+  ep.y <- 0
+
+let () =
+  let p = new point 0 0 in
+  p#print;
+  p#dance;
+  p#print;
+  p#dance;
+  p#print;
+  let (_, _, x, y) : int * int * int * int = Obj.magic p in
+  Printf.printf "Broken coord: (%d, %d)\n" x y;
+  evil_reset p
+  p#print