React.Godot

Let's bring declarative and functional UI programming into Godot 4!

I'm mimicking the pattern popularized by React.js.

The idea

When you use React.Godot library, you define your UI tree

• in a declarative and functional style, resulting in clean and maintainable code,
• with extra discipline,
• without any caching or optimization.

The React.Godot library automatically caches information and optimize the information propagation for you.

Discipline: what you have to adhere to

A react node must (Recommended: copy from "ReactNodeTemplate.cs"):

• Implements IReactable.
• Props are private and marked with [ReactProp].
• States are private and marked with [ReactState].
• All other fields must be immutable after _Ready().
• Has exactly three public methods: SetProps(...), React(), and _Ready().
  • SetProps(...) and React() are auto-generated by metaprogramming.
• Its constructor takes no arguments.
• In Declare(), read only props and states, and nothing else.
  • e.g. don't read system time. Don't read Godot node attributes.
  • The control flow should visit each godot node attribute assignment exactly once. e.g.,
    • don't return from Declare() early.
    • don't put a node attribute assignment in an if branch.
  • Similarly, visit each SubNode.SetProps(...) exactly once.
• Props (and state values) must be immutable.

The python metaprogrammer

• Populates SetProps(...) according to props.
• Provides {state_name}_ attributes as shorthands for getting and setting states.