A totally acceptable way of producing a reverse range in Ruby.

reverse_range.rb

#!/usr/bin/env ruby

class CoolNum
  attr :x

  def initialize(x)
    @x = x
  end

  def succ
    CoolNum.new(@x - 1)
  end

  def <=>(other)
    -@x <=> other.x
  end

  def to_s
    sprintf "%d", @x
  end
end

(CoolNum.new(10)..CoolNum.new(0)).each { |i| puts i }

10
9
8
7
6
5
4
3
2
1
0