Lua介绍
LUA是一种可扩展的编程语言，它被设计成了支持通用编程方式以及通用数据类型的编程语言。它对面向对象編程，函数式編程，数据驱动编程也提供了很好的支持。LUA是一个强大的轻量脚本语言，可被所需的应用程序所调用。LUA的实现方式为库，用Clean C编写的，是C与C++的子集。
作为一种可扩展的编程语言，LUA并没有主程序（main）的概念，它只是嵌入于宿主程序当中运行（运行LUA的应用程序被称之为宿主程序）。宿主程序调用LUA函数去执行一段LUA代码，就可以读写LUA变量，可以注册被LUA调用的C函数。LUA还支持了C函数，所以LUA可以被增强，以应对各种各样的使用场景。因此可以创造了自定义的编程语言，共享同一个语法框架。LUA发布包里包含一个样本宿主程序，叫LUA（解释器）。它利用LUA库提供一个完整，独立的解释器。
1 – Introduction
Lua is an extension programming language designed to support general procedural programming with data description facilities. It also offers good support for object-oriented programming, functional programming, and data-driven programming. Lua is intended to be used as a powerful, light-weight scripting language for any program that needs one. Lua is implemented as a library, written in clean C that is, in the common subset of ANSI C and C++).
Being an extension language, Lua has no notion of a “main” program: it only works embedded in a host client, called the embedding program or simply the host. This host program can invoke functions to execute a piece of Lua code, can write and read Lua variables, and can register C functions to be called by Lua code. Through the use of C functions, Lua can be augmented to cope with a wide range of different domains, thus creating customized programming languages sharing a syntactical framework. The Lua distribution includes a sample host program called lua, which uses the Lua library to offer a complete, stand-alone Lua interpreter.