#!/usr/local/bin/ruby
class Null
end
NULL = Null.new
NULL.freeze
verbose = $VERBOSE
$VERBOSE = nil
NULL.methods.each do |m|
  Null.class_eval { undef_method m }
end
$VERBOSE = verbose
Object.send :remove_const, :Null
def null() NULL end

if __FILE__ == $0
  puts "RUBY_VERSION = #{RUBY_VERSION}"
  def try
    p caller
    begin
      yield
    rescue => ex
      p ex
    end
  end
  try { p null }
  try { p +null }
  try { p !!null }
  try { p "#{null}" }
  try { p null.equal? null }
  try { p null.class }
  try { p null.methods }
  try { p Marshal.dump(null) }
  try {
    h = {:null => null}
    p h.keys
    p h
  }
  try {
    h = {null => :null}
    p h.values
    p h
  }
  try {
    def null.yes
      true
    end
    p null.yes
  }
end