基于closure的lua面向对象编程

事实上lua对于oop并没有语言上的支持（也即没有class之类的关键字），但是我们却可以利用lua本身来实现一些类似oop的效果，基本思路上有两种，基于table和基于closure的，以下是两种方案的一个大致比较

+---------------------------------------+---------------------------+-------------------------------------------------+
| Subject                               | Tables approach           | Closured approach                               |
+---------------------------------------+---------------------------+-------------------------------------------------+
| Speed test results                    | 47 sec.                   | 38 sec.                                         |
| Memory usage test results             | 48433 Kbytes              | 60932 Kbytes                                    |
| Methods declaration form              | Messy                     | More clean                                      |
| Private methods                       | Fine                      | Fine                                            |
| Public methods                        | Fine                      | Fine                                            |
| Private variables                     | Not available             | Fine                                            |
| Public variables                      | Fine                      | Fine                                            |
| Polymorphism                          | Fine                      | Fine                                            |
| Function overriding                   | Ugly (namespace flooding) | Fine (if we grant access only to direct parent) |
| Whole class definition (at my taste)  | Pretty messy              | Kinda clean                                     |
+---------------------------------------+---------------------------+-------------------------------------------------+

从上面的比较中，我们可以看到，除了内存使用一项外，closure方案完胜，因此我们主要来看一下基于closure的实现方案

首先我们来看两个c++的类

class CBase
{
	private:

		CBase();

		virtual ~CBase();

	public:

		static CBase* create();

		void publicMethod();

		static void publicStaticMethod();

		virtual void virtualMethod();

	private:

		void privateMethod();

		static void privateStaticMethod();

	public:

		static int mPublicStaticVar;

		int mPublicVar;

	private:

		int mPrivateVar;

		static int mPrivateStaticVar;

};

class CDerived: public CBase
{
	public:

		static CDerived* create();

		virtual void virtualMethod();
};

Base.lua

module("Base", package.seeall)

mPublicStaticVar = 1

local mPrivateStaticVar = 2


local function privateStaticMethod()
    print("privateStaticMethod called")
end

function publicStaticMethod()
    print("publicStaticMethod called")
end

function create()
    local self = {
        mPublicVar = 3,
    }

    local mPrivateVar = 4

    local function privateMethod()
        print("privateMethod called")
    end

    function self.publicMethod()
        print("publicMethod called")
    end

    function self.virtualMethod()
        print("virtual Method called from Base")
    end

    return self
end

module("Derived", package.seeall)

require("example.Base")

function create()
    local self = Base.create()

    local baseVirtualMethod = self.virtualMethod
    function self.virtualMethod()
        baseVirtualMethod()
        print("virtualMethod called from Derived")
    end

    return self
end

require("example.Derived")

Base.mPublicStaticVar = 1
Base.publicStaticMethod()

local base = Base.create()
base.virtualMethod()
base.publicMethod()
base.mPublicVar = 3
print(base.mPublicVar)

local derived = Derived.create()
derived.virtualMethod()
derived.publicMethod()
derived.mPublicVar = 4
print(derived.mPublicVar)

基于closure的lua面向对象编程,布布扣,bubuko.com

基于closure的lua面向对象编程

原文：http://blog.csdn.net/hopingwhite/article/details/19980473