gistfile1.txt

class Class
  def attr_accessor_with_history(attr_name)
    attr_name = attr_name.to_s   # make sure it's a string
    attr_reader attr_name        # create the attribute's getter
    attr_reader attr_name+"_history" # create bar_history getter
    class_eval #"your code here, use %Q for multiline strings"
  end
end

class Foo
  attr_accessor_with_history :bar
end

f = Foo.new()
f.bar = 1
f.bar = 2
f.bar_history

metaprogramming.rb:6:in `class_eval': block not supplied (ArgumentError)
	from metaprogramming.rb:6:in `attr_accessor_with_history'
	from metaprogramming.rb:11:in `<class:Foo>'
	from metaprogramming.rb:10:in `<main>'

Sample Return Output
[nil, 1, 2]