An ETA class to allow intuitive access to an estimated time of arrival

eta.rb

# Thanks Ellie and Robert! http://www.ruby-forum.com/topic/187604
# Allows relative times, most frequently used in times of arrival etc.
class ETA < Time
  # Takes a number of seconds until the event
  def self.new(seconds)
    raise "ETA requires a number of seconds" if not seconds.is_a?(Numeric)
    at Time.now + seconds
  end
  
  # Requires http://gist.github.com/116290
  def to_s
    roughly
  end
  
  # Gives a full textual representation of the time expected time of arrival (Time.rfc2822)
  def eta
    rfc2822
  end

  # Has the eta passed?
  def arrived?
    self < Time.now
  end
end