lua OOP实现对象的链式调用

数学中的链式法则

http://sx.zxxk.com/ArticleInfo.aspx?InfoID=164649

链式微分法则：

实数运算的链式法则：

对数运算的链式法则：

平行公理的链式法则：

向量运算的链式法则：

JS对象链式调用方法

http://stackoverflow.com/questions/15029309/how-to-write-jquery-chainable-functions-for-local-usinghttp://stackoverflow.com/questions/15029309/how-to-write-jquery-chainable-functions-for-local-using

ar obj = {
    test : function(){
        alert("Y");
        return this;
    },
    test2 : function(){
        alert("2");
        return this;
    }
}
obj.test().test2(); // And so on since it returns this

lua OOP实现

--

-- Class helper routines

--

-- Instantiates a class

local function _instantiate(class, ...)

local inst = setmetatable({__class=class}, {__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

--- 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

local ChainClass = class()

ChainClass.setFlag = function ( self, flag )

self.flag = flag

print("set flag = "..flag)

return self

end

ChainClass.setType = function ( self, type )

self.type = type

print("set type = "..type)

return self

end

ChainClass.printAttrs = function ( self, flag )

for k,v in pairs(self) do

print("name="..k.." value="..tostring(v))

end

return self

end

local chainObj = ChainClass()

chainObj:setFlag(1):setType(2):printAttrs()