module Utils::IRB::Shell

def irb_open(url = nil, &block)
  case
  when url
    system 'open', url
  when block
    Tempfile.open('wb') do |t|
      t.write capture_output(&block)
      t.rewind
      system 'open', t.path
    end
  when url = receiver_unless_main(method(__method__))
    irb_open url
  else
    raise ArgumentError, 'need an url or block'
  end
end