From: Guido van Rossum <guido@digicool.com> To: python-announce-list@python.org Subject: RELEASED: Python 2.2a1 Date: Wed, 18 Jul 2001 09:58:56 -0400 Are you worried that Python 2.2 will break all your old Python code? Don't be! Help us make Python 2.2 as compatible and stable as any release before it. I've released the first alpha release, Python 2.2a1, for your perusal. Download it from: http://www.python.org/2.2/ Give it a good try, and report what breaks to the bug tracker: http://sourceforge.net/bugs/?group_id=5470 New features in this release include: - *TENTATIVELY*, a new way of introspecting instances of built-in types (PEP 252) and the ability to subclass built-in types (PEP 253) have been added. This falls under the header of "type/class unification". More about this below. - Iterators (PEP 234) and generators (PEP 255) were added. The second PEP adds a new reserved word, "yield", which must be enabled by adding "from __future__ import generators" to the top of every module that uses it. Without that, "yield" is treated as an identifier but a warning is issued. - Fredrik Lundh's xmlrpclib is now a standard library module. This provides full client-side XML-RPC support. For the full list of changes, see the release notes on SourceForge: http://sourceforge.net/project/shownotes.php?release_id=43931 As usual, Andrew Kuchling is writing a gentle introduction to the most important changes (currently excluding type/class unification), titled "What's New in Python 2.2": http://www.amk.ca/python/2.2/ Regarding the changes for type/class unification: these have *TENTATIVE* status. While I've done my best to make them backwards compatible, it's unavoidable that a few things may break. In particular, programs doing introspection (looking inside objects to find out what they are) will find that things have changed. I believe the changes are for the better: for example, you can now find out the methods defined for socket objects, and their docstrings, without actually opening a socket. The purpuse of the alpha cycle is to decide whether to go forward with these changes. It's unlinkely, but possible, that we run into unexpected snags during alpha testing, and I may even have to withdraw the changes completely if we conclude they break too much code and we can't fix it any other way. More likely, the second alpha release will introduce fixes to improve the backwards compatibility. In the mean time, for those of you using the CVS tree, these changes are not checked in on the trunk, but on a branch tagged "descr-branch". I'm writing an introduction to the type/class unification: http://www.python.org/2.2/descrintro.html This currently isn't finished yet, but it already contains a list of the most visible backwards incompatibilities. I hope to complete it this week. Until then, please refer to PEP 252 and PEP 253. These aren't intended as tutorials, but they do have most of the information you might be looking for. Here's the URL for the PEP index: http://www.python.org/peps/ Thanks to everybody who contributed to this release. Special thanks go to Tim Peters, who worked through the night to build the Windows installer using an uncooperative installer maker. Enjoy! --Guido van Rossum (home page: http://www.python.org/~guido/) -- http://mail.python.org/mailman/listinfo/python-announce-list