[英]Lua OOP: Problems with tables
There some problems with my OOP. 我的OOP有一些问题。 I have parent with clear table and child with same table.
我的父母有明确的表,孩子有相同的表。 When i'm trying to add object to table of child, object adds to parent's table.
当我尝试将对象添加到子表时,对象添加到父表。
Simple example: 简单的例子:
Account = {}
Account.__index = Account
Account.kit = {}
function Account.create(balance)
local acnt = {} -- our new object
setmetatable(acnt,Account) -- make Account handle lookup
acnt.balance = balance -- initialize our object
return acnt
end
function Account:withdraw(amount)
self.balance = self.balance - amount
end
-- create and use an Account
acc = Account.create(1000)
acc:withdraw(100)
table.insert(acc.kit, "1")
print(#Account.kit)
print(#acc.kit)
Result is 1 and 1. But must be 0 and 1. 结果为1和1。但必须为0和1。
How i can isolate child table from parent? 我如何将子表与父表隔离?
In Lua using acc.kit
where acc
is a table with the metatable Account
will first search the key kit
from the table acc
and then from table Account
. 在Lua中,使用
acc.kit
其中acc
是带有元表Account
的表)将首先从表acc
搜索密钥kit
,然后从表Account
搜索密钥kit
。
In your code acc
does not have anything with key kit
, so the Account.kit
will be accessed. 在您的代码中
acc
没有任何密钥kit
,因此Account.kit
将被访问。
You can solve this simply by defining the kit table for the acc on creation 您可以通过定义用于创建acc的套件表来解决此问题
Account = {}
Account.__index = Account
Account.kit = {} -- You can now remove this if you do not use it - I preserved it to make the test prints to still work.
function Account.create(balance)
local acnt = {} -- our new object
setmetatable(acnt,Account) -- make Account handle lookup
acnt.balance = balance -- initialize our object
acnt.kit = {} -- define kit to be a subtable
return acnt
end
Example: https://repl.it/B6P1 示例: https : //repl.it/B6P1
I'd recommend using closures to implement OOP: 我建议使用闭包来实现OOP:
local Animal = {}
function Animal.new(name)
local self = {}
self.name = name
function self.PrintName()
print("My name is " .. self.name)
end
return self
end
--now a class dog that will inherit from animal
local Dog = {}
function Dog.new(name)
-- to inherit from Animal, we create an instance of it
local self = Animal.new(name)
function self.Bark()
print(self.name .. " barked!")
end
return self
end
local fred = Dog.new("Fred")
fred.Bark()
fred.PrintName()
output: 输出:
Fred barked! 弗雷德咆哮!
My name is Fred 我叫弗雷德
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.