Non-Access Specifiers

Unlike access specifiers, non-access specifiers do not modify the access control of a member, but rather provide other functionality for classes.

Final

Using this non-access specifier will make the given class final, meaning this class now cannot be inherited by other classes.

local class, final = ClassPP.class, ClassPP.final

local Car = final { class "Car" {
    Public = {
        Brand = "Ford",
    }
}}

local BiggerCar = Car.extends "BiggerCar" { -- This will error!
    Public = {
        Brand = "Tesla"
    }
}

Abstract

Using this non-access specifier will make the given class an abstract class, meaning this class now cannot be used to create objects. To access an abstract class, it must be inherited from another class.

local class, abstract = ClassPP.class, ClassPP.abstract

local BaseCar = abstract { class "BaseCar" {
    Public = {
        Brand = "",
        Model = "",
        Year = 0,
        honk = function(self)
            print("honk honk!")
        end
    }
}}

local Car = BaseCar.extends "Car" {
    Public = {
        Brand = "Ford",
        Model = "Mustang",
        Year = 2023
    }
}

local newBaseCarObj = BaseCar.new() -- This will error!
local newCarObj = Car.new() -- This will work fine!
newCarObj:honk()

Warning

You cannot make a class both abstract and final, as they have opposite meanings. An abstract class must be subclassed, whereas a final class cannot be subclassed. Attempting to form an illegal combination between final and abstract methods will cause an error.