You can also pass function object as argument of LuaSandboxFunction::call():$lua = new LuaSandbox();$phpLuaFunction = $lua->wrapPhpFunction(function ($arg){ echo "LUA> ".$arg;});$lua->loadString("print = ...")->call($phpLuaFunction);$lua->loadString(' print("print test from lua\\n")')->call();result:LUA> print test from lua