lua chunk

lua_chunk.hpp

#pragma once

#include <string>

#include <lua/lua.hpp>
#include <luabind/luabind.hpp>
#include <luabind/detail/policy.hpp>
#include <luabind/out_value_policy.hpp>
#include <luabind/operator.hpp>

class lua_chunk {
public:
	lua_chunk(lua_State* L, const std::string& script) {
		lua_chunk::L = L;
		compile(script);
	}

	lua_chunk(lua_State* L) {
		lua_chunk::L = L;
	}

	bool compile(const std::string& script) {
		is_compiled = false;

		//luaL_loadstring(L, script.c_str()) || lua_pcall(L, 0, LUA_MULTRET, 0))
		const int res = luaL_loadstring(L, script.c_str());
		if (res != LUA_OK) {
			const char *msg = lua_tostring(L, -1);
			errors = msg ? msg : "unknown error";

			//switch (res)
			//{
			//case LUA_ERRSYNTAX:
			//	break;
			//case LUA_ERRFILE:
			//	break;
			//default :
			//	break;
			//}
			return false;
		}
		is_compiled = true;
		using namespace luabind;
		chunk = object(from_stack(L, -1));
		//lua_pop(L, 1);

		for (int index = 1;;++index) { // find _ENV upvalue, then use it index to changing chunk ENV for reEVAL.
			auto upv = luabind::getupvalue(chunk, index);
			auto name = std::get<0>(upv);
			static std::string _ENV_NAME = "_ENV";
			if (!name) break;
			if (name == _ENV_NAME) {
				ENV_index = index;
				break;
			}
			// std::cout << name << std::endl;
		}
		//is_compiled = true;
		return is_compiled;
	}

	const std::string& get_errors() const { return errors;	}

	luabind::object run(luabind::object env) {		
		using namespace luabind;

		if (!is_compiled) return object();

		if (env) {
			setupvalue(chunk, 1, env);
		}
		else {
			object _G = rawget(globals(L), "_G");
			setupvalue(chunk, 1, _G);
		}

		luabind::function<luabind::object> chunk_func = chunk;
		return chunk_func();
	}

	luabind::object new_instance() {
		using namespace luabind;
		object oldEnv = rawget(globals(L), "_G");
		object newEnv = newtable(L);
		object newEnvMeta = newtable(L);
		settable(newEnvMeta, "__index", oldEnv);
		setmetatable(newEnv, newEnvMeta);
		run(newEnv);
		return newEnv;
	}

	std::string errors;
	bool is_compiled = false;
	//luabind::function<luabind::object> chunk;
private:
	luabind::object chunk;
	int ENV_index = -1;
	lua_State* L;
};