table_oop3.lua

-- remember, doc comments starts with --- (three dashes).

local a = collectgarbage("count") * 1024

--- Docs for SuperClass (this is a Metatable)
local SuperClass = {
	__tostring = function()
		return "SuperClass.__tostring method."
	end,
}

--- Docs for SuperClass
--- @class SuperClass
local super_class = {}

--- Docs for inherited_method
super_class.inherited_method = function()
	return "this is an inherited method"
end

setmetatable(super_class, SuperClass)

-----------------------------------------------------------------------------------------------

--- Docs for Class (this is a Metatable)
local Class = {
	__tostring = function()
		return "Class.__tostring method"
	end,
}

-- private attrs should be defined here (function local scope)
local private = "this is a private attr"

--- Docs for get_private
local function get_private()
	return private
end

--- Docs for the instance
--- @class Class : SuperClass
local class = super_class

--- Docs for public_field
class.public_field = "this is a public attr"
class.get_private = get_private
setmetatable(class, setmetatable(Class, SuperClass))

----------------------------------------- Here a Demo -----------------------------------------

local i = class

print(class)

-- This would print `nil`. but it is commented because it also produces an LS warning
-- print(i.private_field)

print(i)
print(i.public_field)
print(i.get_private())
print(i.inherited_method())

local b = collectgarbage("count") * 1024
print("\nBytes before instantiation: " .. a .. " Bytes")
print("Bytes after instantiation:  " .. b .. " Bytes")
print("Estimated Bytes running:    " .. b - a .. " Bytes")
-----------------------------------------------------------------------------------------------

-- Making the Class table local, you need to import it where you want to use it:
--     local Class = require("this_file")
--     local i = Class.new()
-- Alternatively, you can make it global, so you can use it just requiring the file (is not recommended):
--     require("this_file")
--     local i = Class.new()
return Class