From: Rasputin <someone@...>
Date: 2004-05-14T19:48:52+09:00
Subject: range problem

From the Pickaxe book:

class VU
  include Comparable

  attr :volume

  def initialize(volume)  # 0..9
    @volume = volume
  end

  def inspect
    '#' * @volume
  end

  # Support for ranges
  def <=>(other)
    self.volume <=> other.volume
  end

  def succ
    raise(IndexError, "Volume too big") if @volume >= 9
    VU.new(@volume.succ)
  end
end

irb(main):001:0> require 'vu'
=> true
irb(main):002:0> r = VU.new(0)..VU.new(9)
=> ..#########
irb(main):003:0> r.to_a
IndexError: Volume too big
        from ./vu.rb:20:in `succ'
        from (irb):3:in `each'
        from (irb):3:in `to_a'
        from (irb):3

Shouldn't the 0 to 9 range be possible?
Apparently 0 to 8 etc. works.
The succ method should only be raising the exception when @volume is 9
but to me it looks like it's raising the error at 8.

I'm not sure if it's a bug or something I'm doing wrong.