let rec move_botleft (z : 'a zipper) : 'a zipper =
(* returns z if the targetted node in z has no children *)
- (* else returns move_botleft (zipper which results from moving down and left in z) *)
- YOU SUPPLY THE DEFINITION
+ (* else returns move_botleft (zipper which results from moving down from z to the leftmost child) *)
+ _____
+ (* YOU SUPPLY THE DEFINITION *)
let rec move_right_or_up (z : 'a zipper) : 'a zipper option =
(* if it's possible to move right in z, returns Some (the result of doing so) *)
(* else if it's not possible to move any further up in z, returns None *)
(* else returns move_right_or_up (result of moving up in z) *)
- YOU SUPPLY THE DEFINITION
+ _____
+ (* YOU SUPPLY THE DEFINITION *)
let new_zipper (t : 'a tree) : 'a zipper =