Terry: agreed. Does anyone actually use this module? Does anyone know what the design goals are for tokenize? If someone can tell me, I'll do my best to make it meet them.

Meanwhile, here's another bug. Each character of trailing whitespace is tokenized as an ERRORTOKEN.

    Python 3.3.0a0 (default:c099ba0a278e, Aug  2 2011, 12:35:03) 
    [GCC 4.2.1 (Based on Apple Inc. build 5658) (LLVM build 2335.15.00)] on darwin
    Type "help", "copyright", "credits" or "license" for more information.
    >>> from tokenize import tokenize,untokenize
    >>> from io import BytesIO
    >>> list(tokenize(BytesIO('1 '.encode('utf8')).readline))
    [TokenInfo(type=57 (ENCODING), string='utf-8', start=(0, 0), end=(0, 0), line=''), TokenInfo(type=2 (NUMBER), string='1', start=(1, 0), end=(1, 1), line='1 '), TokenInfo(type=54 (ERRORTOKEN), string=' ', start=(1, 1), end=(1, 2), line='1 '), TokenInfo(type=0 (ENDMARKER), string='', start=(2, 0), end=(2, 0), line='')]