NodeTree

NodeTree is a framework to create large scalable programs and games through a tree of processes. Each process is fully autonomous and is capable of storing its own state or data, and communicating with other processes. These processes are known as Nodes.

⚠️WARNING⚠️ This crate is in early development. Beware of possible bugs or safety violations.

Getting Started!

Simply either run cargo add node_tree at the terminal directed towards the directory of your project, or add node_tree = X.X to your cargo.toml file.

To begin creating a program in Rust that utilizes a NodeTree, we must first create a root Node. In order to reduce boilerplate, we will use the included NodeSys derive macro to implement the required Dynamic and NodeAbstract traits. We will then implement the Node trait ourselves.

use node_tree::prelude::*;


#[derive(Debug, Clone, Abstract)] // Nodes require `Debug` and `Clone`.
pub struct NodeA {
    base: NodeBase   // Required for Nodes.
}

impl NodeA {
    fn new(name: String) -> Self {
        NodeA { base: NodeBase::new(name) }
    }
}

// Example implementation of the Node trait with custom behaviours.
impl Node for NodeA {

    /// Runs once the Node is added to the NodeTree.
    fn ready(&mut self) {

        // To show off how you could add children nodes.
        if self.depth() < 3 {
            let new_depth: usize = self.depth() + 1;
            
            self.add_child(NodeA::new(format!("{}_Node", new_depth)));
            self.add_child(NodeA::new(format!("{}_Node", new_depth)));
            self.add_child(NodeA::new(format!("{}_Node", new_depth)));
        }

        if self.is_root() {
            println!("{:?}", self.children());
        }
    }

    /// Runs once per frame. Provides a delta value in seconds between frames.
    fn process(&mut self, delta: f32) {

        // Example of using the delta value to calculate the current framerate.
        println!("{} | {}", self.name(), 1f32 / delta);

        // Using the NodePath and TreePointer, you can reference other nodes in the NodeTree from this node.
        if self.is_root() {
            match self.get_node::<NodeA>(NodePath::from_str("1_Node/2_Node1/3_Node2")) {
                Some(node) => println!("{:?}", node),
                None       => ()
            }
        }

        // Nodes can be destroyed. When destroyed, their references from the NodeTree are cleaned up as well.
        // If the root node is destroyed, then the program automatically exits. (There are other ways to
        // terminate the program such as the queue_termination() function on the NodeTree instance).
        if self.children().is_empty() {
            self.free();   // We test the progressive destruction of nodes from the tip of the tree
                           // to the base.
        }
    }

    /// Runs once a Node is removed from the NodeTree, whether that is from the program itself terminating or not.
    fn terminal(&mut self) {}   // We do not do anything here for this example.

    /// Returns this node's process mode.
    /// Each process mode controls how the process() function behaves when the NodeTree is paused or not.
    /// (The NodeTree can be paused or unpaused with the pause() or unpause() functions respectively.)
    fn process_mode(&self) -> ProcessMode {
        ProcessMode::Inherit    // We will return the default value, which inherits the behaviour from
                                // the parent node.
    }
}

Finally, in order to activate our NodeTree, we must instance the root Node and feed it into the NodeTree constructor.

// ...previous implementations
use node_tree::trees::tree_simple::TreeSimple;


fn main() -> () {

    // Create the tree.
    let root: NodeA           = NodeA::new("Root".to_string());
    let tree: Box<TreeSimple> = TreeSimple::new(root, LoggerVerbosity::NoDebug);

    // Begin operations on the tree.
    while tree.process().is_active() {}
}

Node Scenes

You may also input a NodeScene when initializing a NodeTree or adding a child via add_child:

use node_tree::prelude::*;


let scene: NodeScene = scene! {
    NodeA("Root") { // Nodes must have a constructor named `new()` in order for this to work!
        NodeA("1_Node") {
            NodeA("2_Node") {
                NodeA("3_Node"),
                    NodeA("3_Node"),
                    NodeA("3_Node")
            },
            NodeA("2_Node") {
                NodeA("3_Node"),
                NodeA("3_Node"),
                NodeA("3_Node")
            },
            NodeA("2_Node") {
                NodeA("3_Node"),
                NodeA("3_Node"),
                NodeA("3_Node")
            }
        }
    }
};

// Scenes can also be cloned, stored, and reused.
let _ = scene.clone();

Logging

Logging is also supported. Here is an example setup with an output of a warning and a crash. Note that the crash header/footer are customizable, and that the output is actually colored in a real terminal.

use node_tree::prelude::*;
use node_tree::trees::tree_simple::TreeSimple;


#[derive(Debug, Clone, Abstract)]
pub struct NodeA {
    base: NodeBase
}

impl NodeA {
    fn new() -> Self {
        NodeA {
            base: NodeBase::new("NodeA".to_string())
        }
    }
}

impl Node for NodeA {
    fn ready(&mut self) {
        if self.depth() == 2 && self.name() == "NodeA1" {
            self.post(Log::Warn("Failed to Initialize!"));
        }
        
        if self.depth() == 1 && self.name() == "NodeA" {
            self.get_node::<NodeA>(NodePath::from_str("Foo/Bar")).unwrap();
        }
    }
}


fn test_tree_pointer() {
    let scene: NodeScene = scene! {
        NodeA {
            NodeA,
            NodeA,
            NodeA {
                NodeA,
                NodeA,
                NodeA
            }
        }
    };

    let mut tree: Box<TreeSimple> = TreeSimple::new(scene, LoggerVerbosity::All);
    while !tree.process().has_terminated() {}
}

About Cloning

All nodes are expected to implement the Clone trait since there are a few implementations that depend on it, such as NodeScene. However, it is possible to mark a field of a node so that it either has a special clone attribute or is uncloneable via provided types by this crate:

use node_tree::prelude::{ Doc, Eoc, Voc }; // All of these types implement Deref & DerefMut!

#[derive(Debug, Clone, Abstract)]
pub struct SpecializedNode {
    base:   NodeBase,
    resets: Doc<YourUniqueTypeHere>,  // Grabs the ::default() of your type when cloned!
    errors: Eoc<YourUncloneableType>, // Panics when cloned! Good as an assertion.
    voids:  Voc<YourUnownableType>    // Doesn't panic when cloned, but the cloned copy is unusable.
}

Features