Introduction to Loc (Lua Objective-C)

Recently we were starting to use Lua in our game. Lua is a very popular scripting language in the game industry. It’s written in pure C and is very lightweight. We can simply add Lua source code to our project, and it is very easy to compile and run.

However, in practice we encountered issues with type conversion between Lua and Objective-C. In the beginning, we followed instructions to create C functions, and inside the functions we called Objective-C methods, then registered those functions into Lua State as library. When requirements went more complicated, we have to create a bunch of C functions, which are redundancy in a lot of places. This is really not an ideal to bridge between Lua and Objective-C.

After reading the Lua instructions for two days, and with knowledge about iOS7 JavaScript Framework, I decided to create a similar framework to handle type conversion between these two languages. The good thing is Objective-C is a superclass of C, and Lua is naturally compiled from C, this makes it very easy to construct a bridge and make them communicating with each other. With reflection from Objective-C, it’s also very convenient to call Objective-C methods from Lua.

Loc (Lua Objective-C) is the framework I created to convert type between Lua and Objective-C for our project. It’s as simple as Lua, with only 6 packages. It reduces a lot of time to create functions mapping Lua call, and it works pretty well so far.

With the permission from my company, I shared the slides that I presented to my colleagues about the design and syntax about Loc. I am trying to persuade my managers to make it open source, so more developers could use it to prove the usability and make the framework more mature.