Codea classes and objects -- copy constructor required?

Questions
1

I am trying to get a handle on how objects work in Codea. I was surprised by the output of the following code snippet. Thing is a class with a single member variable called self.x.

bob = Thing()
bob.x = 12
dave = bob
dave.x = 7
print("Dave's x-value: " .. dave.x)     -- Outputs 7
print("Bob's x-value: " .. bob.x)     -- Also outputs 7

So it seems that dave is a reference to bob, not a stand-alone instance of the Thing class.
Is there a way to create a copy of an object that is not a reference? Do I need to implement a copy constructor, and if so, how do I do that in Codea?

Thanks!

2 
Thing = class()

function Thing:init( objToCopy )
    if objToCopy ~= nil then
        self.x = objToCopy.x
    end
end

```


Using it:


bob = Thing()
bob.x = 12

dave = Thing(bob)
dave.x = 7

```


That simulates a "copy constructor". However I would suggest having a specific copy method, as it's easier to reason about the calling code and leaves the init method for construction only.


Thing = class()

function Thing:init(x, y)
    -- Normal constructor
    self.x = x
    self.y = y
end

function Thing:copy()
    local copyOfThing = Thing()

    -- Copy fields from self...
    copyOfThing.x = self.x
    copyOfThing.y = self.y

    return copyOfThing
end

```


Using it:


bob = Thing()
bob.x = 12

dave = bob:copy()
dave.x = 7

```
3

Thanks for the response, and I take your point about having a designated copy function. I think I’ve got this working now (both in the silly bob/dave example and in the real stuff I’m working on).

Thanks!