cocos2dx-lua class

cocos2dx-lua function.lua 定义了class方法，让lua实现继承像传统语言一样漂亮和方便

看定义

function class(classname, super)    local superType = type(super)    local cls    --如果父类既不是函数也不是table则说明父类为空    if superType ~= "function" and superType ~= "table" then        superType = nil        super = nil    end    --如果父类的类型是函数或者是C对象    if superType == "function" or (super and super.__ctype == 1) then        -- inherited from native C++ Object        cls = {}        --如果父类是表则复制成员并且设置这个类的继承信息        --如果是函数类型则设置构造方法并且设置ctor函数        if superType == "table" then            -- copy fields from super            for k,v in pairs(super) do cls[k] = v end            cls.__create = super.__create            cls.super    = super        else            cls.__create = super            cls.ctor = function() end        end        --设置类型的名称        cls.__cname = classname        cls.__ctype = 1        --定义该类型的创建实例的函数为基类的构造函数后复制到子类实例        --并且调用子数的ctor方法        function cls.new(...)            local instance = cls.__create(...)            -- copy fields from class to native object            for k,v in pairs(cls) do instance[k] = v end            instance.class = cls            instance:ctor(...)            return instance        end    else        --如果是继承自普通的lua表,则设置一下原型，并且构造实例后也会调用ctor方法        -- inherited from Lua Object        if super then            cls = {}            setmetatable(cls, {__index = super})            cls.super = super        else            cls = {ctor = function() end}        end        cls.__cname = classname        cls.__ctype = 2 -- lua        cls.__index = cls        function cls.new(...)            local instance = setmetatable({}, cls)            instance.class = cls            instance:ctor(...)            return instance        end    end    return clsend

写个测试代码，注意出错的部分

local Base = class('Base')Base.__index = Basefunction Base:ctor(id)    print('Base:ctor',id)    self.id = idendlocal ExtBase = class('ExtBase',Base)ExtBase.__index = ExtBasefunction ExtBase:ctor(id)    --Base:ctor(id)    super(self,id)    print('ExtBase:ctor',id)end

受传统语言影响，会在子类调用基类的构造函数，而事实上，这导致直接将类型本身作为对象实例传入

导致self指向是那个类型本身(也是个table)

那就只能这么写了

Base.ctor(self,id)

有点丑了样，封装一下super函数，看起来好看一点。。

function super(o,...)    --if (o and o.super and o.super.ctor) then        o.super.ctor(o,...)    --endend