// prototype definitions use ES5 getters and setters, too. I would
// need to abandon most (if not all) use of getters and setters ...
-// ~~ (c) SRW,
29 Oct 2012
+// ~~ (c) SRW, Oct 2012
// recursively to make sure none of those are closed, either.
// Because order isn't important, use of `ply` is justified.
+ flag = is_closed(val);