Lua tutorial part 3. paste 2.

-- test.lua
player = Character.new("Hero", 100)
player:setHealth(80)

healer = Character.new("Healer", 100)
merchant = Character.new("Merchant", 100)

hp = player:getHealth()
name = player:getName()
print("Character name: "..name..". HP = "..hp)

function Healer_interact(first, second)
    if(player:getHealth() < 50) then
        first:heal(second)
    else
        first:say("You're gonna be allright, "..second:getName())
    end
    first:say("Hello, let me heal your wounds, "..second:getName())
end

function Merchant_interact(first, second)
    first:say("Do you have money? No? Then get out!")
end

// main.cpp
extern "C" {
# include "lua.h"
# include "lauxlib.h"
# include "lualib.h"
}

#include <iostream>
#include <string>
#include "luawrapper.hpp"

class Character {
public:
    Character(const char* name, int hp);
    void say(const char* text);
    void heal(Character* character);
    const char* getName() { return name;}
    int getHealth() { return health; }
    void setHealth(int hp) { health = hp; }

    void interact(lua_State* L, Character* second);
private:
    const char* name;
    int health;
};

void Character::interact(lua_State* L, Character* second) {
    std::string functionName = name + std::string("_interact");
    lua_getglobal(L, functionName.c_str());
    luaW_push(L, this);
    luaW_push(L, second);
    lua_pcall(L, 2, 0, 0);
}

Character::Character(const char* name, int hp) {
    this->name = name;
    health = hp;
}

void Character::say(const char* text) {
    std::cout<<name<<":"<<text<<std::endl;
}

void Character::heal(Character* character) {
    character->setHealth(100);
}

Character* Character_new(lua_State* L) {
    const char* name = luaL_checkstring(L, 1);
    int hp = luaL_checknumber(L, 2);
    return new Character(name, hp);
}

int Character_getName(lua_State* L) {
    Character* character = luaW_check<Character>(L, 1);
    lua_pushstring(L, character->getName());
    return 1;
}


int Character_getHealth(lua_State* L) {
    Character* character = luaW_check<Character>(L, 1);
    lua_pushnumber(L, character->getHealth());
    return 1;
}

int Character_setHealth(lua_State* L) {
    Character* character = luaW_check<Character>(L, 1);
    int hp = luaL_checknumber(L, 2);
    character->setHealth(hp);
    return 0;
}

int Character_say(lua_State* L) {
    Character* character = luaW_check<Character>(L, 1);
    const char* text = luaL_checkstring(L, 2);
    character->say(text);
    return 0;
}

int Character_heal(lua_State* L) {
    Character* character = luaW_check<Character>(L, 1);
    Character* character2 = luaW_check<Character>(L, 2);
    character->heal(character2);
    return 0;
}

static luaL_Reg Character_table[] = {
    { NULL, NULL }
};

static luaL_Reg Character_metatable[] = {
    { "getName", Character_getName },
    { "getHealth", Character_getHealth },
    { "setHealth", Character_setHealth },
    { "say", Character_say },
    { "heal", Character_heal},
    { NULL, NULL }
};

static int luaopen_Character(lua_State* L) {
    luaW_register<Character>(L, "Character", Character_table, Character_metatable, Character_new);
    return 1;
}

int main() {
    lua_State* L = luaL_newstate();
    luaL_openlibs(L);
    luaopen_Character(L);
    if (luaL_loadfile(L, "test.lua")) {
        std::cout<<"Error, can't open script"<<std::endl;
    }

    lua_pcall(L, 0, 0, 0);
    lua_getglobal(L, "player");
    Character* player = luaW_to<Character>(L, -1);
    lua_getglobal(L, "healer");
    Character* healer = luaW_to<Character>(L, -1);
    lua_getglobal(L, "merchant");
    Character* merchant = luaW_to<Character>(L, -1);

    healer->interact(L, player);
    merchant->interact(L, player);
    std::cout<<"Now player's HP is "<<player->getHealth()<<std::endl;
    int x;
    std::cin>>x;
}