exception_label.rb

module AcmeHttp
  module Error; end
end

begin
  begin
    raise IOError, "Some IO error"
  rescue Exception => error
    error.extend(AcmeHttp::Error)
#    class << error; p self.ancestors; end
#    p  error.singleton_class.ancestors # for 1.9.2
    raise
  end
rescue AcmeHttp::Error => error
  puts "Rescued AcmeHttp::Error: #{error}"
end