Lua脚本实现面向对象-继承

最新推荐文章于 2024-11-20 11:00:30 发布

原创最新推荐文章于 2024-11-20 11:00:30 发布 · 284 阅读

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#lua #开发语言

本文详细解释了Lua中的class函数如何创建类，重点在于new方法，涉及super类型判断、继承自C++对象与Lua对象的区别，以及metatable的使用。

每个Lua脚本开头都会有 local ClassName = class("className", super)

class()方法的具体实现也很简单，重点还是new()方法，其中会自动调用创建类的ctor()方法，话不多说，直接上代码

function class(classname, super)
	local superType = type(super)
	local cls
	if superType ~= 'function' and superType ~= 'table' then
		superType = nil
		super = nil
	end

	if superType == 'function' or (super and super.__ctype == 1) then
		-- inherited from native C++ Object
		cls = {}
		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
		cls.__cname = classname
		cls.__ctype = 1

		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
		-- 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
			if instance.ctor ~= nil then
				instance:ctor(...)
			end
			return instance
		end
	end
	return cls
end