LUA OOP编程实现方法
lua原生不支持OOP特性
确实如此， 同时可以采用其它lua代码的方式实现OOP的特性。
OOP四大特性
抽象
封装
继承
多态
http://www.cnblogs.com/xiaosongluffy/p/5072501.html
四大基本特性：
抽象：提取现实世界中某事物的关键特性，为该事物构建模型的过程。对同一事物在不同的需求下，需要提取的特性可能不一样。得到的抽象模型中一般包含：属性（数据）和操作（行为）。这个抽象模型我们称之为类。对类进行实例化得到对象。
封装：封装可以使类具有独立性和隔离性；保证类的高内聚。只暴露给类外部或者子类必须的属性和操作。类封装的实现依赖类的修饰符（public、protected和private等）
继承：对现有类的一种复用机制。一个类如果继承现有的类，则这个类将拥有被继承类的所有非私有特性（属性和操作）。这里指的继承包含：类的继承和接口的实现。
多态：多态是在继承的基础上实现的。多态的三个要素：继承、重写和父类引用指向子类对象。父类引用指向不同的子类对象时，调用相同的方法，呈现出不同的行为；就是类多态特性。多态可以分成编译时多态和运行时多态。
Code
--
-- Class helper routines
--
-- Instantiates a class
local function _instantiate(class, ...)
local inst = setmetatable({}, {__index = class})
if inst.__init__ then
inst:__init__(...)
end
return inst
end
--- Create a Class object (Python-style object model).
-- The class object can be instantiated by calling itself.
-- Any class functions or shared parameters can be attached to this object.
-- Attaching a table to the class object makes this table shared between
-- all instances of this class. For object parameters use the __init__ function.
-- Classes can inherit member functions and values from a base class.
-- Class can be instantiated by calling them. All parameters will be passed
-- to the __init__ function of this class - if such a function exists.
-- The __init__ function must be used to set any object parameters that are not shared
-- with other objects of this class. Any return values will be ignored.
-- @param base The base class to inherit from (optional)
-- @return A class object
-- @see instanceof
-- @see clone
function class(base)
-- __parent 属性缓存父类，便于子类索引父类方法
return setmetatable({__parent = base}, {
__call = _instantiate,
__index = base
})
end
--[[
local function searchParentClass(k, plist)
for i=1, #plist do
local v = plist[i][k]
if v then return v end
end
end
--- Create a Class object (Python-style object model).
-- The class object can be instantiated by calling itself.
-- Any class functions or shared parameters can be attached to this object.
-- Attaching a table to the class object makes this table shared between
-- all instances of this class. For object parameters use the __init__ function.
-- Classes can inherit member functions and values from a base class.
-- Class can be instantiated by calling them. All parameters will be passed
-- to the __init__ function of this class - if such a function exists.
-- The __init__ function must be used to set any object parameters that are not shared
-- with other objects of this class. Any return values will be ignored.
-- @param base The base class to inherit from (optional)
-- @return A class object
-- @see instanceof
-- @see clone
function class(...)
local mtb = {}
local parents = {...}
mtb = setmetatable(mtb, {
__call = _instantiate,
__index = function(t,k)
return searchParentClass(k, parents)
end})
mtb.__index = mtb
return mtb
end
]]
--- Test whether the given object is an instance of the given class.
-- @param object Object instance
-- @param class Class object to test against
-- @return Boolean indicating whether the object is an instance
-- @see class
-- @see clone
function instanceof(object, class)
local meta = getmetatable(object)
while meta and meta.__index do
if meta.__index == class then
return true
end
meta = getmetatable(meta.__index)
end
return false
end
说明：
1、 通过class来确定继承关系
2、 通过instanceof来判断继承关系
