我很难在Lua的Grokking课程中学习。没有结果的谷歌搜索让我对meta-tables有所了解,并暗示第三方库对模拟/写入类是必要的。如何在Lua中创建类,子类和属性?
下面是一个示例(只是因为我发现我得到更好的答案时,我提供的示例代码):
这是我第一次来翻译上面使用哈维尔提出的技术尝试。
我接受了RBerteig的建议。然而,在派生类中调用仍然产生:"attempt to call method 'methodName' (a nil value)"
--Everything is a table
ElectronicDevice = {};
--Magic happens
mt = {__index=ElectronicDevice};
--This must be a constructor
function ElectronicDeviceFactory()
-- Seems that the metatable holds the fields
return setmetatable ({isOn=true}, mt)
end
-- Simulate properties with get/set functions
function ElectronicDevice:getIsOn() return self.isOn end
function ElectronicDevice:setIsOn(value) self.isOn = value end
function ElectronicDevice:Reboot() self.isOn = false;
self:ResetHardware(); self.isOn = true; end
function ElectronicDevice:ResetHardware() print('resetting hardware...') end
Router = {};
mt_for_router = {__index=Router}
--Router inherits from ElectronicDevice
Router = setmetatable({},{__index=ElectronicDevice});
--Constructor for subclass, not sure if metatable is supposed to be different
function RouterFactory()
return setmetatable ({},mt_for_router)
end
Modem ={};
mt_for_modem = {__index=Modem}
--Modem inherits from ElectronicDevice
Modem = setmetatable({},{__index=ElectronicDevice});
--Constructor for subclass, not sure if metatable is supposed to be different
function ModemFactory()
return setmetatable ({},mt_for_modem)
end
function Modem:WarDialNeighborhood(areaCode)
cisco = RouterFactory();
--polymorphism
cisco.Reboot(); --Call reboot on a router
self.Reboot(); --Call reboot on a modem
if (self.isOn) then self:StartDialing(areaCode) end;
end
function Modem:StartDialing(areaCode)
print('now dialing all numbers in ' .. areaCode);
end
testDevice = ElectronicDeviceFactory();
print("The device is on? " .. (testDevice:getIsOn() and "yes" or "no"));
testDevice:Reboot(); --Ok
testRouter = RouterFactory();
testRouter:ResetHardware(); -- nil value
testModem = ModemFactory();
testModem:StartDialing('123'); -- nil value
您是否阅读过[this](http://lua-users.org/wiki/SimpleLuaClasses)? – ThibThib 2009-07-07 15:01:34