On 2008-11-11 02:10, Steven D'Aprano wrote: > On Mon, 10 Nov 2008 12:51:51 +0000, Duncan Grisby wrote: > >> I have an object database written in Python. It, like Python, is >> dynamically typed. It heavily relies on being able to sort lists where >> some of the members are None. To some extent, it also sorts lists of >> other mixed types. It will be very hard to migrate this aspect of it to >> Python 3. > > No, it is "very hard" to sort *arbitrary* objects consistently. If it > appears to work in Python 2.x that's because you've been lucky to never > need to sort objects that cause it to break.
If you read Duncan's email, he isn't talking about arbitrary objects at all. He's just referring to being able to sort lists that contain None elements. That's far from arbitrary and does work consistently in Python 2.x - simply because None is a singleton which is special cased in Python: None compares smaller to any other object in Python. I'm not sure why this special case was dropped in Python 3.0. None is generally used to be a place holder for a n/a-value and as such will pop up in lists on a regular basis. I think the special case for None should be readded to Python 3.0. -- Marc-Andre Lemburg eGenix.com Professional Python Services directly from the Source (#1, Nov 11 2008) >>> Python/Zope Consulting and Support ... http://www.egenix.com/ >>> mxODBC.Zope.Database.Adapter ... http://zope.egenix.com/ >>> mxODBC, mxDateTime, mxTextTools ... http://python.egenix.com/ ________________________________________________________________________ :::: Try mxODBC.Zope.DA for Windows,Linux,Solaris,MacOSX for free ! :::: eGenix.com Software, Skills and Services GmbH Pastor-Loeh-Str.48 D-40764 Langenfeld, Germany. CEO Dipl.-Math. Marc-Andre Lemburg Registered at Amtsgericht Duesseldorf: HRB 46611 -- http://mail.python.org/mailman/listinfo/python-list
