Tres Seaver wrote:
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:
Yup. Behold: * http://svn.zope.org/DateTime/trunk/ It's currently pulling in the source through an external, but I see no reason why it can't be moved in its own project area. Stuff like DateTime is going to have lots of fixes for already running applications (like timezone fixes, etc.), so having it keep its own release cycle makes sense to me, especially when it's now being evolved towards datetime. The rest of the eggs I created (Acquisition, ExtensionClass, etc.) are mostly independend of the rest of Zope 2 as well and could gain their own projects just as well. Not a full-scale explosion, but just some factoring out... * http://download.zope.org/distribution/DateTime-2.11.0a1.dev-r76287.tar.gz http://download.zope.org/distribution/DateTime-2.11.0a1.dev_r76287-py2.4.egg A ready to go egg of DateTime, completely independent from Zope 2 (only dependencies are zope.interface and zope.testing I believe). -- http://worldcookery.com -- Professional Zope documentation and training