-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Andreas Jung wrote:
--On 25. August 2007 12:33:41 -0400 Tres Seaver <tseaver@palladion.com> wrote:
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Andreas Jung wrote:
Hi,
perhaps the sun burned too long on my brain today but I investigated some options for replacing DateTime with Python's datetime module. Zope 3 uses datetime and we all know that the DateTime implementation sucks. Especially the timezone implementation has a bunch of problems (count the bugtracker issues related to timezone errors).
Constraints: We can not get rid of the DateTime class and its API for backward compatibility reasons.
Idea: The DateTime class remains in place and uses an instance attribute to represent the original value of a DateTime object as instance of datetime. Calls to the old DateTime API are proxied to corresponding calls of the datetime API (or emulated)
Efforts so far: I have some quick-and-dirty implementation that can construct the datetime instance directly within the DateTime constructor and when loading an object from the ZODB (using a custom __setstate__() implementation...could be used for an on-the-fly migration). This seems to work properly. For timezone related issues I am using pytz. However there is a problem with using pytz: the timezone names supported by pytz are sometimes different from the standard one. E.g. 'GMT+0400' is represented in pytz as '/Etc/GMT+0400'...however that seems to be solvable.
Before digging deeper I would like to hear some opinions if this seems a reasonable approach? Unlikely that we can achieve 100% backward compatibility but possibly 99%....thoughts...comments? I'm generally in favor of this, but only if we eggify the *current* DateTime implementation such that people who rely on the incompatible behavior can specify the older version.
Jup, but eggification would likely be the last (and possibly the most easy) step :-)
Eggifying the current package shouldn't be hard (it has no dependencies except for zope.interface. In fact, it looks as though Philipp has done it already: http://mail.zope.org/pipermail/checkins/2007-June/010134.html So releasing an egg from there should be straightforward.
Note that a lot of the code in DateTime is the constructor DWIM, which datetime completely lacks (in fact, the lack of a string-to-datetime parser in the standard library is a major pain). That DWIM *must* remain in place, even in the new version, as too much application code depends on it.
DWIM? The conversion to datetime happens in my place after calling _parse_args() which is a big pita code...if you mean this...yes, I would _never_ touch it.
The parsing is what I meant, along with the DWIM related to number of arguments passed to the constructor. Tres. - -- =================================================================== Tres Seaver +1 540-429-0999 tseaver@palladion.com Palladion Software "Excellence by Design" http://palladion.com -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFG0I9P+gerLs4ltQ4RAjIoAJ42UYkVxnqmjQxIVavDbE33URBoqACfad00 7hoDj7oxRy+KyhdrlxqidIA= =QvY6 -----END PGP SIGNATURE-----