Tree Struct

A general-purpose Tree implementation in Rust.

Trees and Nodes

A Tree is essentially an owned Node with content, children, and no parent. Most of the time, you will be dealing with mutably and immutably borrowed Nodes. Create a Tree with NodeBuilder.

Nodes can be mutably borrowed with from their tree with Tree::borrow_descendant, then you can change the content of the Node, or append children. Nodes can also be detached from the Tree with Tree::detach_descendant, but that does not require a mutable reference to the Node.

Iterators

You can iterate over all the Nodes of a Tree or a subtree (borrowed Node) using Breadth-first or Depth-first Search algorithms. The iterators can be used to find a Node that you want to detach or append to another Node.

Iterators for mutable Nodes

Mutable iterators (Iterator<Item = &mut Node>) are unsafe due to the fact that they yield mutable references to every Node. A child of the yielded Nodes can then be immutably borrowed with node.children(), but the same child will be yielded in a future iteration. Now mutable and shared references to the same Node exist simultaneusly, which is unsafe.

A better (and safe) alternative to mutable iterators is using the immutable iterators (IterBFS and IterDFS) and mutably borrowing a descendant from the Tree.