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Initialize and minimal interop

This page assumes Install and Lua versions is done. Goal: see both C# calling Lua and Lua calling C# during Editor Play. For a fuller 5-minute walkthrough, see Quick start; this page is the formal start of the Guides mainline.

Canonical: Bootstrap.cs, Demo.cs, app.lua

1. Register the loader and Initialize​

using System.IO;
using System.Text;
using UnityEngine;
using ZLua;

public class Bootstrap : MonoBehaviour
{
    private static string LoadLuaModule(string module)
    {
#if UNITY_EDITOR
        string path = Path.Combine(Application.dataPath, "..", "LuaScripts", module + ".lua");
#else
        string path = Path.Combine(
            Application.streamingAssetsPath, "LuaScripts", module + ".lua.txt");
#endif
        return File.Exists(path) ? File.ReadAllText(path, Encoding.UTF8) : null;
    }

    [RuntimeInitializeOnLoadMethod(RuntimeInitializeLoadType.BeforeSceneLoad)]
    private static void InitZLuaOnStartup()
    {
        LuaAppDomain.Initialize(LoadLuaModule);
    }
}
  • module is a logical name (no path, no extension), e.g. "app"
  • Return a UTF-8 source string; return null if not found
  • You do not need to create a LuaState or register Wrap by hand

2. Minimal C# → Lua​

The Lua module must return a table whose keys are the GetFunction method names:

-- LuaScripts/app.lua
local function main()
    print("lua main start")
end

local function add(a, b)
    return a + b
end

return {
    main = main,
    add = add,
}
Action AppMain;
Func<int, int, int> AppAdd;

void Awake()
{
    // 须在 Initialize 之后；勿放在与 RuntimeInitializeOnLoadMethod 同类型的 static 字段初始化器里
    AppMain = LuaAppDomain.GetFunction<Action>("app", "main");
    AppAdd = LuaAppDomain.GetFunction<Func<int, int, int>>("app", "add");
}

void Start()
{
    AppMain();
    Debug.Log(AppAdd(10, 20)); // 30
}

Cache Delegates yourself on hot paths; GetFunction does not guarantee the same instance. Details: C# calling Lua.

3. Minimal Lua → C#​

// Assets/Demo.cs（示意）
public class Demo
{
    public static int Add(int a, int b) => a + b;
    public int x;
    public void SetX(int v) => x = v;
    public int GetX() => x;
}
CSharp['AC'] = CSharp['Assembly-CSharp']

print(CSharp.AC.Demo.Add(3, 5))   -- 8  静态方法

local demo = CSharp.AC.Demo()     -- 构造
demo:SetX(10)
print(demo.x)                     -- 10 字段 / 无参 Property

Types with a namespace must use bracket keys: CSharp.AC['MyGame.UI.Panel']. Day-to-day usage: Lua calling C#.

Expected output (Editor Play)​

lua main start
...
30

If there is no output: confirm BeforeSceneLoad ran, LoadLuaModule("app") is not null, and Console is not filtering Debug. More diagnosis: Troubleshooting.

Next steps​

The next page covers Player builds (Generate, Sync). The interop APIs themselves are the same in Editor / Player; a Player without Generate fails at runtime.

Learning path​

PreviousInstall & Lua version
NextBuild pipeline