Create, read, update, delete

Tree CRUD APIs

A tree can be created via Tree::new() which constructs the root node only with associated data.

#![allow(unused)]
fn main() {
use trees::Tree;
let mut tree = Tree::new(9);
}

This will construct a tree composed of only one root node with data 9.

.............
.     9     .
.............

The root node can be accessed via Tree::root()/Tree::root_mut().

#![allow(unused)]
fn main() {
let root = tree.root();
assert!( root.has_no_child() );
}

The associated data can be read/updated via Tree::data()/Tree::data_mut().

#![allow(unused)]
fn main() {
assert_eq!( root.data(), &9 );

let root = tree.root_mut();
*root.data_mut() = 0;
}

The root data has been modified:

.............
.     0     .
.............

A tree can adopt other trees as children via Tree::push_back().

#![allow(unused)]
fn main() {
tree.push_back( Tree::new(1) );
tree.push_back( Tree::new(2) );
}

This will add two child nodes.

.............
.     0     .
.   /   \   .
.  1     2  .
.............

The child nodes can be accessed via iter().

#![allow(unused)]
fn main() {
let iter = tree.iter();
assert_eq!( iter.next().unwrap().data(), &1 );
assert_eq!( iter.next().unwrap().data(), &2 );
}

Specially, the first/last child can be accessed via front()/back().

#![allow(unused)]
fn main() {
assert_eq!( tree.front().unwrap().data(), &1 );
assert_eq!( tree.back() .unwrap().data(), &2 );
}

A node can adopt other trees as children via Node::push_back().

#![allow(unused)]
fn main() {
let node_1 = tree.front_mut().unwrap();
node_1.push_back( Tree::new(3) );
node_1.push_back( Tree::new(4) );
node_1.push_back( Tree::new(5) );
}

The tree will be:

.............
.     0     .
.   /   \   .
.  1     2  .
. /|\       .
.3 4 5      .
.............

Nodes can be removed via Node::detach().

#![allow(unused)]
fn main() {
let tree_4 = node_1.iter_mut().nth(1).unwrap().detach();
}

The tree will be:

.............
.     0     .
.   /   \   .
.  1     2  .
. / \       .
.3   5      .
.............

Specially, the first/last child can be removed via pop_front()/pop_back().

#![allow(unused)]
fn main() {
node_1.pop_front();
}

The tree will be:

.............
.     0     .
.   /   \   .
.  1     2  .
.  |        .
.  5        .
.............

Forest CRUD APIs

The Forest's APIs are similar with Tree's. The main difference is that a Forest does not have root data, and may be empty.

Node CRUD APIs

The Node's APIs are similar with Tree's. The main difference is that Nodes provided to library users are always in the form of &Node<_> or Pin<&mut Node<_>>, which do not have ownership.