Built up instances and default assets.

src/duck/instance.rs

@@ -18,6 +18,8 @@ impl<S: Asset> DefaultAsset<S> {
 
 pub trait Class {
     fn new(entity: &mut EntityWorldMut) -> AnyInstance;
+    fn load(entity: &mut EntityWorldMut) -> AnyInstance { Self::new(entity) }
+    fn reload(entity: &mut EntityWorldMut) {}
     fn add_fields<T, F: LuaUserDataFields<T>>(_fields: &mut F) {}
     fn add_methods<T, F: LuaUserDataMethods<T>>(_methods: &mut F) {}
     fn class_name() -> &'static str {"Instance"}

src/duck/script.rs

@@ -2,6 +2,8 @@ use std::ops::Deref;
 use bevy::asset::AsyncReadExt;
 use bevy::prelude::*;
 use bevy::asset::{io::Reader, AssetLoader, LoadContext};
+use bevy::ecs::system::SystemId;
+use mlua::Lua;
 use thiserror::Error;
 use crate::duck::instance::*;
 
@@ -43,9 +45,23 @@ impl Class for Script {
     fn new(entity: &mut EntityWorldMut) -> AnyInstance {
         let handle = DefaultAsset::<ScriptAsset>::clone(entity.world());
         entity.entry().or_insert(Script(handle));
+        let world = entity.world();
+        Self::run(entity);
         AnyInstance::Script(Instance::new(entity))
     }
 }
+impl Script {
+    fn run(entity: &mut EntityWorldMut) {
+        let lua = &entity.world().get_resource::<DefaultScriptContext>().unwrap().0;
+        let script_assets = entity.get_resource::<Assets<ScriptAsset>>().unwrap();
+        let script_asset_handle = &entity.get::<Script>().unwrap().0;
+        let script = script_assets.get(script_asset_handle).unwrap();
+        lua.load(script.source.clone()).exec().unwrap();
+    }
+}
+
+#[derive(Resource)]
+struct DefaultScriptContext(Lua);
 
 pub fn startup(
     mut commands: Commands,
@@ -54,6 +70,7 @@ pub fn startup(
     DefaultAsset::new(&mut commands,script_assets.add(ScriptAsset {
         source: "print(\"Hello world!\")".into()
     }));
+    commands.insert_resource(DefaultScriptContext(Lua::new()));
 }
 
 pub fn setup(app: &mut App) {