I’d like in my next project make modding API and Lua seems to be perfect language for the task. It is fast, flexible and easy to sandbox. But is it possible to integrate it into Unity game? Had it been done?
If you really searched for it you should have found this page. In the C# section the last one (UniLua) is a 100% managed implementation of lua optimised for Unity3d. I haven’t tested it yet, but it’s “mostly” complete. Some features are missing or not done yet. See for yourself.
The big advantage of 100% managed code is that you can run it even in webbuilds or mobile builds and don’t require Unity pro (for plugin support). Wrappers only work for a certain platform.
It’s possible to integrate it to C, therefore its possible to integrate it to C#. I personally have never done it, but I know someone on a former team that has made an interop library for the three languages. So, I assume possible to integrate it into Unity once you have a C# DLL.
Edit
You can reate your own DLL, or use one that’s already exists, such as LuaInterface. Then, I think its all a matter of how much you know about integrating Lua.
If I recall correctly this was a pretty good tutorial for using LuaInterface in C#.