need traceback info where a calling lua code error occurs.

[tungfaifong]

when I call lua code, an error occurs, but there is only error message, sometimes need some calling stack info.
it will be better where an lua error occurs, append a traceback to error message.

[kunitoki]

Can't you use lua_pcall and pass a error handler which does lookup the lua debug.traceback and prints it ?

inline int traceback(lua_State* L)
{
    // look up Lua's 'debug.traceback' function
    lua_getglobal(L, "debug");
    if (!lua_istable(L, -1))
    {
        lua_pop(L, 1);
        return 1;
    }

    lua_getfield(L, -1, "traceback");
    if (!lua_isfunction(L, -1))
    {
        lua_pop(L, 2);
        return 1;
    }

    lua_pushvalue(L, 1);
    lua_pushinteger(L, 2);
    lua_call(L, 2, 1);
    
    lua_getglobal(L, "print");
    if (!lua_isfunction(L, -1))
    {
        lua_pop(L, 1);
        return 1;
    }

    lua_pushvalue(L, 1);
    lua_call(L, 1, 0);
    
    return 1;
}

int main()
{
    lua_pushcfunction(L, &traceback);

    if (luaL_loadstring(L, "<your script here>") != LUABRIDGE_LUA_OK
        || lua_pcall(L, 0, 0, -2) != LUABRIDGE_LUA_OK)
    {
        auto errorString = lua_tostring(L, -1);
        std::cerr << (errorString ? errorString : "Unknown lua error") << "\n";
    }
}