Lua机器人示例

bot.lua

--发送信息：
--send_message(group_id,discuss_id,user_id,msg)
--该函数返回发送信息文本的长度

--收到信息时的回调函数
--如果成功返回0，其他值表示出错
function on_receive_message(group_id,discuss_id,user_id,msg)
	if #msg==0 then
		msg="[未输入]"
	end
	msg="用户："..user_id.."<"..msg
	if discuss_id~=0 then
		msg="讨论组："..discuss_id.." "..msg
	end
	if group_id~=0 then
		msg="群："..group_id.." "..msg
	end
	send_message(group_id,discuss_id,user_id,msg)
	return 0
end

LuaBot.cpp

#include <iostream>
#include <string>

#include "lua.hpp"

#pragma comment(lib,"lua54.lib")

#define PushFunctionToLua(lua_state,lua_cfunction) lua_register(lua_state,_CRT_STRINGIZE(lua_cfunction),lua_cfunction)
#define LUA_CFUNCTION(function_name,lua_state) int function_name(lua_State* lua_state)

lua_State* luaState = nullptr;

//调用Lua函数
//on_receive_message(group_id,discuss_id,user_id,msg)
lua_Integer lua_call_on_receive_message(int64_t group_id,int64_t discuss_id,int64_t user_id,std::string msg)
{
    lua_getglobal(luaState, "on_receive_message");
    //从左到右push参数
    lua_pushinteger(luaState, group_id);
    lua_pushinteger(luaState, discuss_id);
    lua_pushinteger(luaState, user_id);
    lua_pushstring(luaState, msg.c_str());
    if (lua_pcall(luaState, 4, 1, 0))//调用完成后会自动把函数和参数从栈中清除，因此下方的-1改成1也可以
    {
        puts(lua_tostring(luaState, -1));//lua_pcall出错时会返回一个错误对象
        return -1;
    }
    return lua_tointeger(luaState, -1);
}

//在Lua中调用的C函数
//send_message(group_id,discuss_id,user_id,msg)
LUA_CFUNCTION(send_message,L)
{
    //获取参数
    int64_t group_id = lua_tointeger(L, 1);
    int64_t discuss_id = lua_tointeger(L, 2);
    int64_t user_id = lua_tointeger(L, 3);
    std::string msg = lua_tostring(L, 4);
    //函数实际代码
    std::cout << msg << std::endl;
    //push返回值
    lua_pushinteger(L, msg.length());//被调用时不用清栈，直接放入返回值就行
    return 1;//这个函数返回1个值
}

int InitLua()
{
    int e = 0;
    luaState = luaL_newstate();//创建Lua环境
    if (!luaState)
    {
        std::cerr << "创建Lua失败。\n";
        return -1;
    }
    luaL_openlibs(luaState);//加载Lua自带库
    if (LUA_OK != (e = luaL_dofile(luaState, "bot.lua")))//执行Lua文件
    {
        std::cerr << "执行文件失败，错误：" << e << std::endl;
        return -2;
    }
    PushFunctionToLua(luaState, send_message);//将回调函数推至Lua
    return 0;
}

void UninitLua()
{
    lua_close(luaState);
}

int main()
{
    if (InitLua())
    {
        std::cerr << "错误 InitLua.";
        return -1;
    }
    std::cout << "Lua 交互示例\n输入文字后按 Enter.\n";
    std::string input;
    lua_Integer e = 0;
    do
    {
        std::cout << ">";
        std::getline(std::cin, input);
        if (e = lua_call_on_receive_message(0, 0, 0, input))
        {
            std::cout << "错误 on_receive_message:" << e;
            break;
        }
    } while (input.length());
    UninitLua();
    return 0;
}