This is a fork of the indextree crate which allows to remove nodes. The original version was not capable of removing nodes as the initial idea was to drop all nodes at the same time if the lifetime of the underlying memory arena has ended.

The arena tree structure is using a single Vec, a HashMap and numerical identifiers. Every node holds an id which is mapped to an index of the vector via the HashMap. This allows to drop single nodes before the lifetime of the arena hash ended.

There is no RefCell and mutability is handled in a way much more idiomatic to Rust through unique (&mut) access to the arena.

use indextree_ng::Arena;

// Create a new arena
let arena = &mut Arena::new();

// Add some new nodes to the arena
let a = arena.new_node(1);
let b = arena.new_node(2);

// Append b to a
a.append(b, arena);
assert_eq!(b.ancestors(arena).into_iter().count(), 2);

//Access a node
assert_eq!(arena[b], 2);

// Remove a node
arena.remove_node(a);
assert_eq!(b.ancestors(arena).into_iter().count(), 1);