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()
puts f
f.bar = 1
f.bar = 2
f.bar_history