ParentMother = {}

 function ParentMother:MortherName()

     print("Morther name : HanMeimei")

 end

 return ParentMother

 ParentFather = {}

 function ParentFather:FatherName()

     print("Father name : LiLei")

 end

 return ParentFather

 require "ParentMother"

 require "ParentFather"

 Daughter = {}

 --不是 Daughter 中一个方法

 local function Search(key,BaseList)

     for i=,#BaseList do

         local val = BaseList[i][key]

         if val then

             return val

         end

     end

     return nil

 end

 --不是 Daughter 中一个方法

 local function CreateClass()

     local parents = {ParentMother,ParentFather}

     setmetatable(Daughter,

         {

             __index = function(t,k)

                 return Search(k,parents)

             end

         })

 end

 function Daughter:new()

     local self = {}

     CreateClass()

     setmetatable(self,{__index = Daughter})

     Daughter.__index = Daughter

     return self

 end

 function Daughter:DaugtherName()

     print("Daugther name : Linda")

 end

 return Daughter

 --[[

 Lua多继承的实现原理:

 也是利用的元表和元表的__index字段，不同于对象实例化和单一继承不同的是__index字段赋值的是一个函数而不是一个基类的表。

 利用传入__index字段的函数来查找类中找不到的字段（函数中遍历该类继承的多个基类）

 --]]

 require "Daughter"

 local child = Daughter:new()

 child:DaugtherName()

 child:MortherName()

 child:FatherName()

 --[[

 运行结果:

 Daugther name : Linda

 Morther name : HanMeimei

 Father name : LiLei

 --]]

 Animal = {}

 function Animal:ShowType()

     print("the is a animal!")

 end

 World = {}

 function World:ShowPosition()

     print("on the earth!")

 end

 local function Search(k, list)

     for i=,#list do

         local tmpVal = list[i][k]

         if tmpVal then

             return tmpVal

         end

     end

     return nil

 end

 local function CreateClass( ... )

     local tab = {}

     setmetatable(tab,{__index = function (_,k)

         return Search(k, arg)

     end})

     tab.__index = tab

     function tab:new(o)

         o = o or {}

         setmetatable(o,tab)

         return o

     end

     return tab

 end

 TestClass = CreateClass(Animal, World)

 local lgs= TestClass:new({""})

 lgs:ShowType();