deprecate UserList? (WAS: Why no list heritable type?)

Steven Bethard steven.bethard at gmail.com
Fri Dec 17 18:36:27 CET 2004


Sion Arrowsmith wrote:
> In article <86vfb13jpl.fsf at guru.mired.org>, Mike Meyer  <mwm at mired.org> wrote:
> 
>>And before Python 2.2 there was the UserList class in the standard
>>library. Which is still there in 2.4. Shouldn't it be depreciated by
>>this point?
> 
> 
> Apart from compatibility issues as mentioned in the UserList
> documentation, deriving from it will give you a classic class,
> whereas deriving from list will give you a new style class.
> There may be circumstances under which this is important
> (exercise left to more twisted minds than mine). Same applies
> to dict/UserDict.

Classic classes will eventually disappear:

http://www.python.org/doc/2.2.3/whatsnew/sect-rellinks.html#SECTION000310000000000000000

GvR also encourages people to use new-style classes for everything:

http://mail.python.org/pipermail/python-dev/2002-March/021817.html

Steve



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