override `require`

[ParadiseFallen]

override `require`

[ParadiseFallen]

using System.Text;

using KeraLua;

using LuaEmbeded;

var script = """

    require('chunk');
    print(_ENV.package);
    -- testPrint("hello world")
    print('test');

    """;

var chunk = """
    
    function testPrint(arg)
        print(arg .. "hook 2");
    end

    """;

// create engine
var luaEngine = new NLua.Lua(false);

// configure encoding
luaEngine.State.Encoding = Encoding.UTF8;

// configure host functions
// there is extension method that cast it to delegate and pass delegate.Method 
luaEngine.RegisterFunction("print", PrintHook<object>);

Delegate x = LoadHook;
luaEngine.RegisterFunction("require", x.Method);

var bytes = Encoding.UTF8.GetBytes(chunk);
luaEngine.State.LoadBuffer(bytes, "chunk");
luaEngine.State.LoadString(chunk,"chunk");
luaEngine.LoadString(chunk, "chunk");

try
{

    var result = luaEngine.DoString(script, "Main");
    foreach (var item in result)
        Console.WriteLine(item);

}
catch (Exception ex)
{
    Console.WriteLine(ex);
}

static void PrintHook<T>(T text) =>
    Console.WriteLine($"Hooked {text}");

void LoadHook(string packageName)
{
    try
    {
      // this method binds fine BUT
        Console.WriteLine(packageName);
        // if uncomment next line it will throw exception even not calling this method
        // luaEngine.DoString("print(123)");
    }
    catch (Exception ex)
    {
        throw;
    }
}

[ParadiseFallen]

UPD: what i found is: https://github.com/NLua/NLua/blob/main/tests/src/LuaTests.cs#L252
so basically you need to set context of delegate
if you change to LuaEngine.RegisterFunction("require", this, LoadHook); it dosent crash at least,

btw extensions is:

public static class Extensions
{

    public static void RegisterFunction(this NLua.Lua lua, string path, Delegate @delegate) =>
        lua.RegisterFunction(path, @delegate.Method);

    public static void RegisterFunction(this NLua.Lua lua, string path, object target, Delegate @delegate) =>
       lua.RegisterFunction(path, target, @delegate.Method);

}

[ParadiseFallen]

after researching found that in hook enough just to DoString and pass chunk there. But there is huge mistake.

Default require method in lua use cache inside lua. if ill override require then import will be not cached

[Hi-ImKyle]

I have never passed a method to Lua with RegisterFunction before but you can just do the following

var lua = new Lua()
lua["require"] = (Action<string>)LoadHook;

This completely overrides the original implementation.

[ParadiseFallen]

@Hi-ImKyle with RegisterFunction i have for some reason many override like f:BeginInvoke() and others. wiered behaviour

[vincywindy]

I use this，it works!

            using var lua = new Lua();
            lua.State.Encoding = Encoding.UTF8;
           lua["require"] = new Func<string, object?>(d =>
            {
                var str = File.ReadAllText(d + ".lua");
            //any other way to load lua string
                var function = lua.DoString(str);
                if (function.Count() == 1)
                {
           //local a= require 'xx' return if has return values
                    return function[0];
                }
                return null;
            });