Issue with Maybe

maybe_example.rb

# Null Object Pattern:
# http://devblog.avdi.org/2011/05/30/null-objects-and-falsiness/

require 'delegate'
                                                                                                                                                                             
RUBY_VERSION # => "2.0.0"

class NullObject
  def method_missing(*args, &block)
    self
  end

  def to_a; []; end
  def to_s; ""; end
  def to_f; 0.0; end
  def to_i; 0; end
end


BasicObject.class_eval do
  def Maybe(value)
    case value
    when nil then NullObject.new
    else value
    end
  end
end



Maybe("test") # => "test"

class Foo
  def test
    Maybe("test")
  end
end

class Bazz < SimpleDelegator
  def test
    Maybe("test")
  end
end

a = Foo.new
a.test  # => "test"
b = Bazz.new("test")
b.test # => "test"	from -:41:in `<main>'

Note for the future: This happens because SimpleDelegator doesn't inherits from Object.

a.class.ancestors # => [Foo, Object, Kernel, BasicObject]
b.class.ancestors # => [Bazz, SimpleDelegator, Delegator, #Module:0x000001010243b8, BasicObject]