Level (or depth) of a node

[giacomoratta]

When I use the Iterator, I would want to know the level of a node.
Is there a (low complexity) way to have the level of a node?

Level: "The level of a node is defined as: 1 + the number of edges between the node and the root."
Depth: "The depth of a node is the number of edges from the tree's root node to the node."
(from Wikipedia)

Would be also interesting to have other characteristics about the tree:

• is Branch node (or is Internal node)
• Height of node
• Height of tree
• Depth

[Joris-van-der-Wel]

There already is a method to figure out if something is an internal vs external node: tree.hasChildren(obj).

Figuring out the depth/level could be sped up by using a cache. On a static tree it would then average out to O(1). This is similar to how tree.index(obj) works (the number of preceding siblings). I think figuring out the height could be done in a similar way. But i'll have to see when i have some time to add this