Create properties and methods Lua C++ - c++

Question

This is rather tricky to explain and I could not find anything on this in the documentation or anywhere on the net so I thought this would be a suitable place for this question.
I'm trying to register properties and methods on an object in Lua using C++.
This is what I'm trying to achieve in Lua:
player = createPlayer()
player:jump() // method
player.x = player.x + 3 // properties
I can easily achieve the first line in the example using C++
int create_player(lua_State *L)
{
Player* player = new Player();
..
return 0;
}
int main(int args, char * argv[])
{
lua_State* L = lua_open();
luaL_openlibs(L);
lua_register(L, "createPlayer", create_player);
luaL_dofile(L, "main.lua");
..
return 0;
}
But how do I create the method :jump() and properties .setX and .getX for createPlayer?

Answer 1

What you could have searched is "Binding C++ to Lua".
Since it's a rather popular question, I'll post an answer with a project compilable online:
Starting from a C++ class:
class Player {
int x;
public:
Player() : x(0) {}
int get_x() const { return x; }
void set_x(int x_) { x = x_; }
void jump() {}
};
You can then create bindings using LuaBridge without writing the boilerplate for each of the bound members yourself:
void luabridge_bind(lua_State *L) {
luabridge::getGlobalNamespace(L)
.beginClass<Player>("Player")
.addConstructor<void (*)(), RefCountedPtr<Player> /* shared c++/lua lifetime */ >()
.addProperty("x", &Player::get_x, &Player::set_x)
.addFunction("jump", &Player::jump)
.endClass()
;
}
Using a dedicated Lua State wrapper LuaState, you can then open a Lua state and perform the bindings:
lua::State state;
luabridge_bind(state.getState());
Running the script using some trace output:
try {
static const char *test =
"player = Player() \n"
"player:jump() \n"
"player.x = player.x + 3"
;
state.doString(test);
}
catch (std::exception &e) {
std::cerr << e.what() << std::endl;
}
Produces the following output:
Player
jump
get_x
set_x 3
~Player
You can see the whole thing live at Travis-CI