CODEWITHSUNDEEP
luaclosures
MARTIN Damien
MARTIN Damien

Reputation: 1026

how to give parameters to closure in lua

I have the following code :

{

    identifier = "hand:" .. card.name,
    area = { x, y, 100, 100 },
    on_click = function()
        -- Code goes here
    end

}

I want to use the card variable and a reference to the object where this code is placed to modify a variable of the class with a value of the card variable.

So, how can I give parameters from the local context to the function who will be called in other pieces of code ?

I wish to launch the on_click function in an event management loop.

Upvotes: 0

Views: 417

Answers (2)

Mike Corcoran
Mike Corcoran

Reputation: 14565

save it when you assign the function, like this

{
    identifier = "hand:" .. card.name,
    area = { x, y, 100, 100 },
    on_click = function()
        local a_card = card
        print(a_card.name)
    end
}

Upvotes: 0

Paul Kulchenko
Paul Kulchenko

Reputation: 26744

If I understand the question correctly, you want to be able to reference from on_click handler the object that on_click handler belongs to. To do this, you need to split the statement you have:

local card = { name = "my card" }
local object = {
  identifier = "hand:" .. card.name,
  area = { x, y, 100, 100 },
}
object.on_click = function()
  -- Code goes here
  -- you can reference card and object here (they are upvalues in this context)
  print(card.name, object.area[3])
end
object.click()

You can also define on_click a bit differently; in this case you get object as implicitly declared self variable (note that you call it a bit differently too):

function object:on_click()
  -- Code goes here
  -- you can reference card and object here
  print(card.name, self.area[3])
end
object:click() -- this is the same as object.click(object)

Upvotes: 1

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