[Python-Dev] Reintroduce or drop completly hex, bz2, rot13, ... codecs (original) (raw)

M.-A. Lemburg mal at egenix.com
Thu Jun 10 13:08:26 CEST 2010

Walter Dörwald wrote:

On 09.06.10 14:47, Nick Coghlan wrote:

On 09/06/10 22:18, Victor Stinner wrote: Le mercredi 09 juin 2010 10:41:29, M.-A. Lemburg a écrit :

No, .transform() and .untransform() will be interface to same-type codecs, i.e. ones that convert bytes to bytes or str to str. As with .encode()/.decode() these helper methods also implement type safety of the return type.

What about buffer compatible objects like array.array(), memoryview(), etc.? Should we use codecs.encode() / codecs.decode() for these types? There are probably enough subtleties that this is all worth specifying in a PEP: - which codecs from 2.x are to be restored - the domain each codec operates in (binary data or text)* - review behaviour of codecs.encode and codecs.decode - behaviour of the new str, bytes and bytearray (un)transform methods - whether to add helper methods for reverse codecs (like base64) The PEP would also serve as a reference back to both this discussion and the previous one (which was long enough ago that I've forgotten most of it). I too think that a PEP is required here.

Fair enough. I'll write a PEP.

Codecs support several types of error handling that don't make sense for transform()/untransform(). What should 'abc'.decode('hex', 'replace') do? (In 2.6 it raises an assertion error, because errors must be strict).

That's not really an issue since codecs don't have to implement all error handling schemes.

For starters, they will all only implement 'strict' mode.

I think we should takt this opportunity to implement transform/untransform without being burdened with features we inherited from codecs which don't make sense for transform/untransform.

Not sure what you mean here. Those methods are just helper methods which interface to the codec system and provide return type safety. Nothing more or less.

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