说明：  Lua开发指南，Lua 是一个小巧的脚本语言。脚本语言不需要事先编译,直接可以运行(其实是在运行的时候进行解释翻译)。该语言的设计目的是为了嵌入应用程序中,从而为应用程序 供灵活的扩展和定制功能。
(Lua development guide, Lua is a small scripting language. Scripting languages do not need to be compiled before they can be run directly (actually interpreted at run time). The language is designed to be embedded in applications so as to provide flexible extensions and customization capabilities for applications.)