Question about MetaTables

So I’m 100% new to metatables and for my new project, I think it would be beneficial to use metatables.

I’m trying to return a table of functions when you call on the table via :Function() and return the actual settings when you call on the table using [“Key”] or just indexing it using Module.Settings.

This is like my code.

local SETTINGS = {--[[Settings]]}

local RMG = {}

RMG.Settings = {}

local SettingsMetatable = {
	__index = function ()
		return SETTINGS
	__call = function ()

function SETTINGS_FUNCS:Function()
    -- Code

Is this possible or should I just ditch that idea altogether and not use metatables?

OOP; Object Oriented Programming, is a very powerful tool. To do this in Lua I usually do the following:

local module = {}
module.__index = module

function -- Creates a new meta table
	local self = {}
	... -- Any misc code you need
	setmetatable(self, module)
	return self

function module:Function()
	-- This passes in self, and this code will execute based on this object.

function module.OtherFunction()
	-- This does not pass in self, and is used as a global function

return module

The __call metamethod is only invoked when you attempt to call a non-function value, the __call metamethod is looked for in the value’s metatable (if it has one set) and if defined the metamethod is ran, otherwise you’ll encounter an ‘attempt to call a table value’ error.

local t = setmetatable({}, {__call = function()
	print("Hello world!")

t() --Hello world!
local t = setmetatable({}, {__call = function(...) --The metamethod is passed the called value (table) and any values that were passed to it.
	local a = {...}
	print(table.unpack(a, 2))

t("Hello", "world!") --Hello world!