Adding to_s to classes

job.rb

class Job
  def initialize(items_to_process)
    @items = items_to_process
    @timestamp = Time.now
    # start_processing in the background...
  end

  def to_s
    if finished?
      "All work is done, all #{@items.size} items are processed."
    else
      "Still working (#{Time.now - @timestamp}s), \
       #{@processed_items.size} of #{@items.size} processed."
    end
  end
end

jobs.rb

ruby> job = Job.new([item1, item2, ...]

ruby> puts job
Still working (2s), 2 of 100 items processed.

ruby> puts job
Still working (4s), 7 of 100 items processed.

...

ruby> puts job
All work is done, all 100 items are processed.

simple_class_with_to_s.rb

class Foo
  def to_s
    "I am a Foo."
  end
end

usage.rb

ruby> foo = Foo.new
ruby> puts foo
I am a Foo.