not.rb: fun with monkey patching with Zach Allaun

not.rb

class Object
  def not
    NotProxy.new(self)
  end
end

class NotProxy
  def initialize(obj)
    @obj = obj
  end
  
  def method_missing(name, *args, &block)
    !@obj.public_send(name, *args, &block)
  end
  
  def respond_to_missing?(*args)
    @obj.respond_to?(*args) || super
  end
end

[1,2,3].not.empty? #=> true