calling a function on a parent from a table

MoKaLux · May 2021

hope you are all doing well

I have this issue and I don't know if what I am trying to do is possible in lua.

I have a table which has a function in it. Now I am passing this table from one class to another.
Is it possible to execute the function on the parent?

Some code for you to see:

Menu.lua:

	...
	local mybtn = ButtonTP9UDDT.new({
		scalexup=1, scalexdown=1.2,
		audio=self:selectionSfxM(), -- this is the function
	}, 1)
	...

ButtonTP9UDDT.lua:

	...
--		if self.params.audio then pcall(self.params.audio) end
--		if self.params.audio then self:getParent():getfenv(self.params.audio) end
		if self.params.audio then
			local fun = self.params.audio
			self:getParent():fun()
--			self.params.audio()
		end
	...

self.params.audio holds the function from the table (checked with type(self.params.audio)).

As you can see, I have tried a couple of things to no avail

Is it possible to call a function in a table on the parent?

Thank you for your time

PS: I can do

if self.params.audio then self:getParent():selectionSfxM() end

but I would like to pass the name of the function in a table, that would be more convenient.

rrraptor · May 2021

Here:

audio=self:selectionSfxM()

you call a function

to pass function as argument:

audio=self.selectionSfxM

and simply call like that:

self.audio(self, other, arguments, here)

or

self:audio(other, arguments, here)

MoKaLux · May 2021

that worked, I thank you a bunch captain rrraptor. Thank you also for the explanations.

what is now working code:
class1:

	local mybtn03 = ButtonTP9UDDT.new({
		scalexup=1, scalexdown=1.2,
		fun=self.myfunction,
	}, 3)

class2:

function ButtonTP9UDDT:init(xparams, xselector)
	self.params = xparams or {}
	self.selector = xselector
 
	self.params.scalexup = xparams.scalexup or nil -- number
	self.params.scaleyup = xparams.scaleyup or self.params.scalexup -- number
 
	self.params.fun = xparams.fun or nil -- function
	if self.params.fun ~= nil and type(self.params.fun) ~= "function" then
		print("*** ERROR ***", "YOU ARE NOT PASSING A FUNCTION", self.selector)
		return
	end
	...
end
 
function ButtonTP9UDDT:onMouseDown(e)
	if self:hitTestPoint(e.x, e.y) and self:getParent():isVisible() then
		self.isfocused = true
		self.isclicked = true
		self:updateVisualState()
		if self.params.fun then self.params.fun(self:getParent()) end
		e:stopPropagation()
	end
end

PS: another alternative would be to add the wanted function directly in the second class, sometimes that is even better this way.

Viva Gideros!

hgy29 · May 2021

Note that you can also pass the function name as a string instead of the function itself, if you see fit. Then you can call it

 object[functionName](object,...)

MoKaLux · May 2021

I don't understand the code hgy29

how does it fit in this? self.params.fun(self:getParent())

EDIT: now with the addition below from hgy29 I think we have all available possibilities

hgy29 · May 2021

(self:getParent())[self.params.fun](self.getParent()]

rrraptor · June 2021

You can remove if statement here:

if self.params.fun then self.params.fun(self:getParent()) end

local function dummy() 
end
 
function ButtonTP9UDDT:init(xparams, xselector)
	...
	self.params.fun = xparams.fun or dummy
	...
end

so you always have a function to call

self.params.fun(self:getParent()) -- no if

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