module Kernel
  #
  # Captures the given stream and returns it:
  #
  #   stream = capture(:stdout) { puts 'Cool' }
  #   stream # => "Cool\n"
  def capture(stream)
    begin
      stream = stream.to_s
      eval "$#{stream} = StringIO.new"
      yield
      result = eval("$#{stream}").string
    ensure
      eval("$#{stream} = #{stream.upcase}")
    end

    result
  end
end