"Robin Stocker" <robin-lists-ruby-talk / nibor.org> solved:
> Here's my solution for Ruby Quiz #34. It's my first one :)

Welcome to Ruby Quiz, Robin!

Here's my solution, which is basically the same as Robin's. I must cite 
NegaPosi by SASADA Koichi for inspiration.

http://www.dave.burt.id.au/ruby/whiteout.rb

Known bug: "__END__" doesn't work in an eval'd string. No solution 
anticipated. NegaPosi has this problem too.

Also, my Whiteout doesn't try and detect whether the given file is a valid 
whiteout file or not, so you'll get a syntax error if you "require 
'whiteout'" with anything else other that a shebang and whitespace in the 
file.

There's an interesting hack at the eval end of my script to make "if $0 == 
__FILE__" blocks work:
  eval "$0 = __FILE__; #{ Whiteout.decode(File.read($0)) }"

Cheers,
Dave