Navigate from a node to its last child N times to reach the Nth level of the
tree, or return Option.none if there is a leaf on the path from root to its
Nth 1st child down.
When n is zero, the zipper is returned unchanged.
Will return Option.none if given negative indexes.
Navigate from a node to its last child N times to reach the Nth level of the tree, or return
Option.noneif there is a leaf on the path from root to its Nth 1st child down.When
nis zero, the zipper is returned unchanged.Will return
Option.noneif given negative indexes.See lastN for an unsafe version.
Type Param: A
The underlying type of the tree.
Param: self
The zipper that will be navigated.
Param: n
Number of tree levels to descend.
Returns
An updated zipper pointing at a new focus or
Option.none()if the path to the Nth level is not valid.