CODEWITHSUNDEEP
c++lua
Zinglish
Zinglish

Reputation: 345

Returning an instance of a C++ object in Lua 5.2?

I have looked at multiple sources and I just do not understand them. Mostly all of them are either using a library like luaBind (Which I do not want to use because it relies on Boost) or they are not already instanced objects in C++ but rather created in Lua directly.

I have a Player class, which is wrapped in another class to handle Lua calling. I have created a std::vector list of both these objects in my initialization of the application.

So basically I do not want the Lua script to be creating these player objects I would just like to create a function getPlayer() which then returns the Lua wrapped object. I have no idea where to start with defining the Lua wrapped object for Lua to call nor do I know how to return an instance of the object to Lua so I can use calls from it.

Here's an example of what I would like my Lua script to look like:

player = getPlayer(1) -- Returns the Lua wrapped object from C++ where 1 is the object's index in the std::vector list
print("Player's name: ", player:name()) -- Print's the player's name

Could someone point me to a decent tutorial that explains how to do this. I am pretty sure that this isn't some sort of "Never been done and why would you want to" case so surely there must be at least one tutorial out there. I have been searching for about 2 days now with no positive results.

Upvotes: 2

Views: 836

Answers (1)

MahanGM
MahanGM

Reputation: 2382

This isn't a Never been done task, but companies which they use Lua have been already done lots of changes and improvements on the raw source of Lua to make it fit in the place that they want. Since all of us programmers are not that cool to do such stuffs on third-parties sources, we have to use whatever exists out there. You think Crytek is using the exact same version of Lua which is resided on its website's repository? No sir.

You can make this happen by using userdata. Or you can use meta tables. There is also another piece of code named Luna which it helps you to achieve faster.

Otherwise, it's all Luabind, and believe me you're going to end up using it one way or another. Besides, its use of Boost is not that broad and there is going to be just 200kb added to the final executable. Check this address if you want to use Luabind sometime, it's really a good article on the web. http://blog.nuclex-games.com/tutorials/cxx/luabind-introduction/

If you're too bored with Lua, I may suggest you to use squirrel as an alternative to Lua. Personally, I prefer squirrel more than Lua because of its C like syntax and its abilities which they are the ones that we want. Besides, you can even declare constants and use real classes in its context which Lua is pretty failed at this. The funny thing about squirrel is that the designer is a guy that he has been working on FarCry on developing Lua for its engine.

Upvotes: 1

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