I was intrigued by the post that _why put up a few days/weeks ago  
about using case/when for testing arrays [1]. I thought I'd give it a  
try but I can't make it work. What am I doing wrong?

irb(main):001:0> r1 = (0..12).to_a
=> [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12]
irb(main):002:0> r2 = (20..32).to_a
=> [20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32]
irb(main):003:0> def foo range
irb(main):004:1>  case range
irb(main):005:2> when *r1
irb(main):006:2>   puts "#{range} in r1"
irb(main):007:2> when *r2
irb(main):008:2>   puts "#{range} in r2"
irb(main):009:2> else
irb(main):010:2*   puts "#{range} NOT in any range"
irb(main):011:2> end
irb(main):012:1> end
=> nil
irb(main):013:0> foo 3
NameError: undefined local variable or method `r1' for main:Object
         from (irb):5:in `foo'
         from (irb):13

This is under OSX:
ruby 1.8.4 (2005-12-24) [powerpc-darwin8.4.0]

[1] http://redhanded.hobix.com/bits/wonderOfTheWhenBeFlat.html