A scenario for the implementation of the LUA OOP singleton pattern

Single case

There is such a class, no matter how the class is initialized, the resulting instance are the same object.

Code

String.tohtmlcode = function (self)

return encodehtml (self)

End

--Instantiates a class

Local function _instantiate (class, ...)

--Singleton mode, if the instance is already generated, return directly

If Rawget (class, "__singleton") Then

--_g[class] value is an instance of this class

If _g[class] Then

return _g[class]

End

End

Local Inst = setmetatable ({__class=class}, {__index = class})

If Inst.__init__ Then

Inst:__init__ (...)

End

--Singleton mode, if the instance is not generated, logs the instance to a class

If Rawget (class, "__singleton") Then

If not _g[class] Then

_g[class] = Inst

End

End

Return Inst

End

--LUA class constructors

Local function class (base)

Local metatable = {

__call = _instantiate,

__index = Base

}

--__parent Property Cache parent class for child class Index parent class method

Local _class = {__parent = base}

--Record metatable in the class object to overload Metatable.__index

_class.__metatable = metatable

Return setmetatable (_class, metatable)

End

Description

Using the method, class inherits the same way

If you set a _singleton to true for the defined class, turn on simple interest mode.

A scenario for the implementation of the LUA OOP singleton pattern