the closest `'#'`. This would allow our task to simulate delimited
continuations with embedded `prompt`s (also called `reset`s).
+<!--
The reason the task is well-suited to the list zipper is in part
because the List monad has an intimate connection with continuations.
We'll explore this next.
+-->
-
+Here is [[some Scheme code|/code/refunctionalizing_zippers.rkt]] implementing the `tz` and `tc` functions, first as presented above, and second with the variant just mentioned, using `'#'`. There's also a third kind of implementation, which is akin to the `tc` version, but doesn't explicitly pass a `k` argument, and instead uses these unfamiliar operations `reset` and `shift`. We'll be explaining what these do shortly. (The reason this code is in Scheme is because that's the language in which it's easiest to work with operations like `reset` and `shift`.)