[Python-Dev] PEP 461 - Adding % and {} formatting to bytes (original) (raw)

Brett Cannon brett at python.org
Thu Jan 16 17:41:03 CET 2014

On Thu, Jan 16, 2014 at 11:33 AM, Michael Urman <murman at gmail.com> wrote:

On Thu, Jan 16, 2014 at 8:45 AM, Brett Cannon <brett at python.org> wrote: > Fine, if you're worried about bytes.format() overstepping by implicitly > calling str.encode() on the return value of format() then you will need > bytes_format() to get equivalent support.

Could we just re-use PEP-3101's note (easily updated for Python 3): Note for Python 2.x: The 'formatspec' argument will be either a string object or a unicode object, depending on the type of the original format string. The format method should test the type of the specifiers parameter to determine whether to return a string or unicode object. It is the responsibility of the format method to return an object of the proper type. If format receives a formatspec of type bytes, it should return bytes. For such cases on objects that cannot support bytes (i.e. for str), it can raise. This appears to avoid the need for additional methods. (As does Nick's proposal of leaving it out for now.)

That's a very good catch, Michael! I think that makes sense if there is precedence. Unfortunately that bit from the PEP never made it into the documentation so I'm not sure if there is a backwards-compatibility worry. -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://mail.python.org/pipermail/python-dev/attachments/20140116/b831b3b1/attachment.html>

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