lua 面向对象

lua 面向对象

概述

lua 的面向对象是通过 table 类型, 使用元表实现的

lua 的继承简单理解来就是方法的一层层包裹, 支持方法重写

普通类

示例程序

Rectangle = {area = 0, length = 0, width = 0}

function Rectangle:new = function(o, length, width)
	o = o or {}
	setmetatable(o, self)
	self.__index = self
	self.length = length or 0
	self.width = width or 0
	self.area = length * width
	
	return o
end

function Rectangle:printArea()
	print("printArea: ", self.area)
end

r = Rectangle:new(nil, 10, 20)
r:printArea()

继承

示例程序

local Shape = {area = 0}
local mtShape = {__index = Shape}

function Shape:new()
	local o = {}
	
	return setmetatable(o, mtShape)
end

function Shape:printArea()
	print("printArea:" .. self.area)
end

local Rect = Shape:new()
local mtRect = {__index = Rect}

function Rect:new()
	local o = {}
	
	return setmetatable(o, mtRect)
end

r = Rect:new()
r:printArea()