Re: A function to create an object using closures
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- Subject: Re: A function to create an object using closures
- From: Matthew Paul Del Buono <delbu9c1@...>
- Date: 2008年11月21日 09:40:02 -0500 (EST)
Hi Michal,
>function Greeting()
>local self = {}
>-- Private attributes and methods
>local message = "Good morning"
>-- Public methods
>self.get = function() return message end
>self.say = function() print(self.get()) end
>return self
>end
I disagree with this here. If you're only creating one Greeting object or only a few, it might be okay, but I think that if you create many, you're going to have an issue with memory.
Generally a metatable is used in the following form:
Greeting = {};
Greeting.__index = Greeting;
function Greeting.new(message)
local self = setmetatable({}, Greeting);
self._message = message;
return self;
end
function Greeting:get()
return self._message;
end
function Greeting:say()
print(self._message);
end
However, there are valid uses for what you specified as well. Both will work; it's up to what you want to do, really. Personally, I'm generally more pressed for memory, so I prefer the metatable approach for frequently used cases.
Regards,
-- Matthew P. Del Buono