local classes = {
    fighter = {
        health = 100, --default health
        takeDamage = function(self, amount)
            self.health = self.health - amount >= 1 and self.health - amount or 0
        end
    }
}

local new = function(type)
    return classes[type:lower()]
end


local enemy = new("fighter")
print(enemy.health) --this will print 100, because the default health is 100
enemy:takeDamage(50) --make the enemy take 50 damage
print(enemy.health) --this will print 50 because the health changed