read-tree

A rust library for creating and then navigating read-only trees.

Usage

Add the following to your cargo.toml file.

[dependencies]
read-tree = "0.2"

Description

This crate provides a library for creating and then querying trees. The trees are not intended to be modified after their initial creation.

Internally trees are represented by a Vec<Vertex<T>> where each vertex carries the payload of that node in the tree and the number of its descendants. In addition the vertices are sorted depth first; meaning every vertex is followed by the vertex of its first child. Using the length of a vertex we can easily skip a nodes entire subtree and can instantly access its sibling.

Slicing a tree into a node is as simple as slicing the trees vertices buffer into a &[Vertex<T>]. We wrap this slice in a Node<T>.

Examples

Trees are created using Saplings. Nodes can be attached to a sapling by using push. When a node is added to a sapling it is also selected as the parent for nodes that are added later. To finish a node and reselect its parent call pop. When adding a node with no children use push_leaf. There are more methods to push other saplings, trees or even nodes. See Sapling for more information.

When the sapling is complete, you can build it into a Tree<T>. The resulting tree can no longer be modified. Navigating trees is done by using slices of trees called Node<T>. To get started use as_node on a tree to get its root node which represents the entire tree.

Nodes support various iterators to navigate their contents.

fn main() -> Result<(), Box<dyn std::error::Error>> {
    use read_tree::Sapling;

    let mut sap = Sapling::new();
    sap.push(1);
    sap.pop();

    let tree = sap.build()?;
    let root = tree.as_node();

    assert_eq!(root.data(), &1);
    Ok(())
}

Changelog

Version 0.2.0

• Breaking changes
  • Removed Node::depth
  • Changed Node::len to no longer includes the node itself in the count
  • Changed Descendants to no longer include the node itself
  • Renamed Node::iter into Node::descendants
• Additions
  • Made Vertex public
  • Added PolyTree
  • Added Ancestors iterator
• Improvements
  • Implemented more traits for error enums
  • Implemented more traits and overrides for iterators

Version 0.1.0

Initial Release.