null date object

If you find yourself checking for nil constantly, a null object of some sort can help.

I wanted to make a null object for dates. Here is the NullDate class I came up with.

class NullDate
  include Comparable
  def strftime format
    "No date yet."
  end
  def to_s
    "No date yet."
  end
  def <=>(other_date)
    Time.new(0000,1,1) <=> other_date
  end
  def to_datetime
    Time.new(0000,1,1).to_datetime
  end
end

I found myself checking for nil all over the place when comparing dates, so I made my NullDate class implement <=>, and just have it compare to Time.new(0000,1,1), which is the lowest time/date value possible. Be sure to implement to_datetime, or you’ll get an error like this:

Here’s an ascii.io screencast I made that demonstrates use of this class!