Struct CursoredTree 

pub struct CursoredTree<T> { /* private fields */ }

Tree with a movable cursor that tracks the current position.

Wraps a Tree<T> and maintains a cursor as a Vec<usize> path from the root. Navigation methods return bool to indicate whether the move succeeded; the cursor is never left in an invalid state.

CursoredTree<T> implements Deref<Target = Tree<T>>, so all read-only Tree methods are available directly. For mutation through the inner tree, use tree_mut.

Implementations

impl<T> CursoredTree<T>

pub fn new(root_value: T) -> Self

Create a new tree with a single root node. The cursor starts at root.

pub fn cursor_path(&self) -> &[usize]

Index path from the root to the current node.

pub fn cursor(&self) -> &[usize]

Alias for cursor_path.

pub fn current(&self) -> &Node<T>

Reference to the node at the cursor.

pub fn current_mut(&mut self) -> &mut Node<T>

Mutable reference to the node at the cursor.

pub fn current_id(&self) -> u64

Id of the node at the cursor.

pub fn has_parent(&self) -> bool

true when the cursor is not at the root.

pub fn has_children(&self) -> bool

true when the current node has at least one child.

pub fn push(&mut self, value: T) -> u64

Add a child to the current node and move the cursor to it.

Always succeeds because the parent is the current node.

pub fn go_parent(&mut self) -> bool

Move the cursor to the parent. Returns false at the root.

pub fn go_child(&mut self, index: usize) -> bool

Move the cursor to the child at index. Returns false if out of bounds.

pub fn go_child_last(&mut self) -> bool

Move the cursor to the last (newest) child. Returns false when there are no children.

pub fn go_sibling_next(&mut self) -> bool

Move the cursor to the next sibling. Returns false when there is no next sibling or the cursor is at the root.

pub fn go_sibling_prev(&mut self) -> bool

Move the cursor to the previous sibling. Returns false when there is no previous sibling or the cursor is at the root.

pub fn go_to(&mut self, id: u64) -> bool

Jump the cursor to the node with the given id. Returns false when the id does not exist.

pub fn go_root(&mut self) -> bool

Move the cursor back to the root. Returns false if already there.

pub fn push_child( &mut self, parent_id: u64, value: T, ) -> Result<u64, ParentNotFound>

Append a child to the node identified by parent_id.

The cursor is not moved. See push for the push-and-move variant.

pub fn remove_subtree(&mut self, id: u64) -> Option<Node<T>>

Remove a subtree. If the cursor was inside the removed subtree, it is repaired to the nearest surviving ancestor.

pub fn prune(&mut self, policy: PrunePolicy)

Prune the tree. If the cursor was on a pruned node, it is repaired to the nearest surviving ancestor.

pub fn tree(&self) -> &Tree<T>

Immutable reference to the inner Tree.

pub fn tree_mut(&mut self) -> &mut Tree<T>

Mutable reference to the inner Tree.

Use with care: structural changes may invalidate the cursor. Call methods on CursoredTree instead when possible.

Methods from Deref<Target = Tree<T>>

pub fn root(&self) -> &Node<T>

Reference to the root node.

pub fn next_id(&self) -> u64

The id that will be assigned to the next inserted node.

pub fn find(&self, id: u64) -> Option<&Node<T>>

Look up a node by id. O(1) amortised.

pub fn find_path_to(&self, id: u64) -> Option<Vec<usize>>

Return the index path from the root to the given id. O(1) amortised.

pub fn dfs(&self) -> DfsIter<'_, T>

Depth-first iterator yielding (depth, &Node<T>) pairs.

pub fn flatten(&self) -> Vec<(usize, &Node<T>)>

Collect dfs into a Vec.

Trait Implementations

impl<T: Clone> Clone for CursoredTree<T>

fn clone(&self) -> CursoredTree<T>

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<T: Debug> Debug for CursoredTree<T>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<T> Deref for CursoredTree<T>

type Target = Tree<T>

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.