[IPython-dev] [Fwd: python2.5]

Fernando Perez Fernando.Perez at colorado.edu
Tue Jul 25 01:14:19 CDT 2006

This is William's original message which got auto-discarded, and to which I 
just replied.

-------- Original Message --------
Subject: python2.5
Date: Mon, 24 Jul 2006 22:59:29 -0700
From: William Stein <wstein at gmail.com>
Reply-To: wstein at gmail.com
Organization: University of Washington
To: Fernando Perez <Fernando.Perez at colorado.edu>
CC: ipython-dev at scipy.net,        "sage-devel at lists.sourceforge.net" 
<sage-devel at lists.sourceforge.net>

Hi Fernando and Ville,

Have you tried Ipython with Python2.5 beta2 yet?   Since Python2.5
is supposed to be released in "early August", it might be worth
thinking about it.  I'm getting SAGE ready for Python 2.5, and
I noticed that IPython is somewhat broken under Python 2.5.
In particular, if you start IPython (with default configuration),
and type

      raise TypeError   # or any other exception

there is a noticeable pause before the traceback.  Even worse,
if code raises an error deep in the call stack, e.g., 8 or 9
levels down, there is a very long pause (e.g., 10 seconds) before
the traceback is displayed.

Note that this weird pause does not occur when using straight python
2.5b with exactly the same code.  Also note that I'm not using pdb.
I noticed that the IPython traceback looks different than Python's
(e.g., no line numbers), so maybe you're doing some interesting magic
there that needs updating for Python 2.5b (or maybe Python 2.5b has
a bug?).

Also, ipdb seems to be completely broken with Python 2.5b.  For
me it will print a traceback and show the prompt, but any attempt
to execute commands, e.g., print names of variables, etc., leads to

ipdb> print n
*** ERROR ***
This version of pdb has a bug and crashed.
Returning to IPython...


Anyway, I understand that IPython makes no claims at all about
supporting Python 2.5.   I just wanted to let you know that Python 2.5
seems to be a huge jump, so much so that somebody might have to put
in some significant effort to make IPython work with it.
If you or somebody doing IPython is interested in this, and doesn't
have time to isntall Python 2.5, I can set up an account for them
on sage.math.washington.edu with Python 2.5 and iPython preinstalled.

William Stein
Associate Professor of Mathematics
University of Washington

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