Struct Tree 

pub struct Tree {
    pub root: Option<NodeIdx>,
    /* private fields */
}

Arena-allocated tree of TreeNodes.

Nodes are stored in a Vec and referenced by their index. This avoids Rc<RefCell<>> while still allowing safe mutation during bottom-up merging and top-down embedding phases.

Fields

root: Option<NodeIdx>

Index of the root node, if the tree has been built.

Implementations

impl Tree

pub fn new() -> Self

Creates an empty tree with no nodes.

pub fn add(&mut self, node: TreeNode) -> NodeIdx

Adds a node to the tree, returning its index.

pub fn get(&self, idx: NodeIdx) -> &TreeNode

Returns a shared reference to the node at the given index.

pub fn get_mut(&mut self, idx: NodeIdx) -> &mut TreeNode

Returns a mutable reference to the node at the given index.

pub fn len(&self) -> usize

Returns the number of nodes in the tree.

pub fn is_empty(&self) -> bool

Returns true if the tree contains no nodes.

pub fn iter(&self) -> impl Iterator<Item = &TreeNode>

Returns an iterator over all nodes in the tree.

pub fn get_pair_mut( &mut self, a: NodeIdx, b: NodeIdx, ) -> (&mut TreeNode, &mut TreeNode)

Simultaneously access two distinct nodes by index (safe, checked).

Trait Implementations

impl Clone for Tree

fn clone(&self) -> Tree

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Tree

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

Formats the value using the given formatter.

impl Default for Tree

fn default() -> Tree

Returns the “default value” for a type.