python-dev Summary for 2005-06-01 through 2005-06-15

Steven Bethard steven.bethard at
Sun Jun 26 00:49:09 CEST 2005

[The HTML version of this Summary is available at]

Summary Announcements

Bug Day: Saturday, June 25th 2005

AMK organized another `Python Bug Day`_ on Saturday, June 25th. Hope
you got a chance to help out!

.. _Python Bug Day:

Contributing Threads:

- `Bug day on the 25th?


FishEye for Python CVS

Peter Moore has kindly set up `Fish Eye for the Python CVS repository`_.
FishEye is a repository browsing,  searching, analysis and monitoring tool,
with great features like RSS feeds, Synthetic changesets, Pretty ediffs and
SQL like searches. Check it out!

.. _Fish Eye for the Python CVS repository:

Contributing Threads:

- `FishEye on Python CVS Repository


PyPy Sprint: July 1st - 7th 2005

The next `PyPy`_ sprint is scheduled right after EuroPython 2005 in
Gothenborg, Sweden. It will focus mainly on  translating PyPy to lower level
backends, so as to move away from running PyPy on top of the CPython
interpreter.  There will be newcomer-friendly introductions, and other
topics are possible, so if you have any interest in PyPy,  now is the time
to help out!

.. _PyPy:

Contributing Threads:

- `Post-EuroPython 2005 PyPy Sprint 1st - 7th July 2005


Reminder: Google's Summer of Code

Just a reminder that the friendly folks at Python have set up a `wiki`_ and
a `mailing list`_ for questions about  `Google's Summer of Code`_. For
specific details on particular projects (e.g. what needs done to complete
Python SSL  support) participants may also ask questions to the Python-Dev

.. _wiki:
.. _mailing list:
.. _Google's Summer of Code:


hashlib Review Request

Gregory P. Smith noted that he has finished up the hashlib work he started
on a few months ago for patches `935454`_  and `1121611`_ (where the final
patch is).  He feels that the patch is ready, and would like anyone
interested to  review it; the patch incorporates both OpenSSL hash support
and SHA256+SHA512 support in a single module.  `The  documentation`_ can be
accessed separately, for convenience.

.. _935454:
.. _1121611:
.. _The documentation:

Contributing Threads:

- `hashlib - faster md5/sha, adds sha256/512 support



PEP 343 Progress

The PEP 343 discussions were mostly concluded. Guido posted the newest
version of the PEP to both Python-Dev and  Python-List and the discussions
that followed were brief and mostly in agreement with the proposal.

The PEP 343 syntax was modified slightly to require parentheses if VAR is a
comma-separated list of variables.  This  made the proposal
forward-compatible to extending the with-block for multiple resources. In
the favored extension,  the with-block would take multiple expressions in a
manner analogous to import statements::

    with EXPR1 [as VAR1], EXPR2 [as VAR2], ...:

However, if this extension becomes part of Python, it will likely enter
some time after Python 2.5, once users have a better idea of what with-block
use-cases look like.

There were also some brief discussions about how with-blocks should behave
in the presence of async exceptions like  the KeyboardInterrupt generated
from a ^C. While it seemed like it would be a nice property for with-blocks
to  guarantee that the __exit__ methods would still be called in the
presence of async exceptions, making such a  guarantee proved to be too
complicated.  Thus the final conclusion, as summarized by Nick Coghlan, was
that "with  statements won't make any more guarantees about this than
try/finally statements do".

Contributing Threads:

- `PEP 343 rewrite complete

- `For review: PEP 343: Anonymous Block Redux and Generator
Enhancements <

- `PEP 343 - next steps

- `PEP 343 question


Do-While Loops

Raymond Hettinger asked for a "dowhile" loop of the form::

    dowhile <cond>:

which would run <body> once before testing the <cond>, and then proceed as a
normal while-loop. He was subsequently  referred to `PEP 315`_, which
proposes a slightly different syntax for a similar purpose.

The discussion expanded to not only do-while loops, but also loops with
break conditions at locations other than the  beginning and the end of a
loop. A variety of syntax proposals were suggested, but none seemed
compellingly better  than the current syntax::

    while True:
        if <cond>:

which supports putting the condition(s) at any location in the loop.

.. _PEP 315:
Contributing Threads:

- `Wishlist: dowhile


Reference Counting in Module Globals

Both Michael Hudson and Skip Montanaro noticed that Py_INCREFs appeared to
be unnecessary when adding an object to a  module's globals. Armin Rigo
explained that after a module is initialized, the import mechanism makes a
"hidden"  copy of the module's dict so that the module can be reloaded. This
means that objects added as module globals will  always have an extra
reference count in this hidden dict.

However, Armin Rigo agreed with Michael Hudson that this explanation was no
longer applicable after an interpreter  shutdown. The best conclusion he
could draw in this a situation: "it's all quite obscure".

Contributing Threads:

- `refcounting vs PyModule_AddObject
- `[Python-checkins] python/dist/src/Modules _csv.c, 1.37, 1.38


Reorganising the standard library (again)

The ever-popular topic of reorganising the standard library came up again
this fortnight, courtesy of Reinhold  Birkenfeld.  The questions posed
included hierarchy (flat/nested), third party modules, size (batteries
included or  not), and the standard GUI toolkit.

As usual, there was a great deal of discussion, but not a great deal of
consensus about any of these (other than  that including ElementTree in the
standard library would be good), and given the amount of breakage this would
involve (and that Guido didn't weigh in at all), it seems unlikely that much
will change before Python 3000;  although Josiah Carlson indicated that he
had a patch that would avoid a lot of breakage.
Contributing Threads:

- `Thoughts on stdlib evolvement


First Mac-tel, now Py-tel?

Guido mentioned that Intel has a free (as in beer) C `compiler for Linux`_,
and that a friend of his (who is  involved in its production and marketing)
would like to see how it performs with Python.  The compiler wasn't news  to
some of the -dev crowd, though, with Martin v. Löwis pointing out a `bug
report on the compiler`_, as well as a  `patch`_, and a `message indicating
that some people had problems`_ with the resulting interpreter.

Martin pointed out that there were some old (2002 and 2004) results
indicating that the Intel compiler was slightly  faster, but couldn't find
any results for the latest version.  Michael Hoffman gave summaries of more
testing, which  gave a 16% speed increase.  He felt that, while this was
significant, he wasted a lot of time dealing with resulting problems with
extension modules, and so it doesn't use as much any more.

.. _compiler for Linux:
.. _bug report on the compiler:
.. _patch:
.. _message indicating that some people had problems:

Contributing Threads:

- `Compiling Python with Intel compiler?


sys.path Behaviour

Reinhold Birkenfeld noticed that sys.path's first element is '' in
interactive sessions, but the directory  containing the script otherwise,
and wondered if this was intentional.  Guido clarified that he's always
liked it  this way, so that if you use os.path.join to join it with a script
name you don't get a spurious ".\" preprended.

The "absolutizing" of sys.path entries, however, is reasonably new; Bob
Ippolito pointed out that is also  `problematic with regards to path
hooks`_.  He has a `patch to fix it`_, but hasn't had a chance to commit it;
Phillip J. Eby noted that the patch doesn't fix completely fix it, however,
and indicated that fixing with  respect to `PEP 302`_ will be quite
.. _problematic with regards to path hooks:
.. _patch to fix it:
.. _PEP 302:

Contributing Threads:

- `sys.path in interactive session


More on old bugs
The discussion about what to do with old bugs continued this fortnight.
Against the concern about prematurely  closing old bugs, there was the
suggestion that given that there are such a huge number of open bug reports,
and  since closed bugs can be reopened, this wasn't such a problem.  It was
suggested that the act of closing a bug might  trigger activity to get it
fixed, if necessary.  The thread died off before a consensus was reached,

Contributing Threads:

- `Closing old bugs


Improved pseudo-switch statements

Skip Montanaro has been playing around with getting the Python compiler to
recognize switch-like statements and  generate O(1) code out of them.  The
rules are that the object being compared ('x') can be any expression, but
must  be precisely the same in each elif clause, the comparison operator
must be "==", and the right-hand-side of the test  must evaluate to a simple
hashable constant.  However, if evaluating 'x' has side-effects, then this
would break  code.

Various people felt that it was unwise to allow 'x' to be any expression;
Anthony Baxter suggested that one could  allow any local object that didn't
define a comparison operator.
Contributing Threads:

- `Multiple expression eval in compound if statement?


Skipped Threads

- `Adventures with Decimal

- `Weekly Python Patch/Bug Summary

- `AST manipulation and source code generation

- `Vestigial code in threadmodule?

- `[Python-checkins] python/dist/src/Lib, 1.57, 1.58

- `Split MIME headers into multiple lines near a space

- `python running in several threads

- `problem installing current cvs

- `b32encode and NUL bytes

- `Example workaround classes for using Unicode with csv module...

- `Weekly Python Patch/Bug Summary

- `[Python-checkins] python/dist/src/Doc/lib libtokenize.tex, 1.5, 1.6

- `Five patch reviews & patch request

- `AIX 4.3, Python 2.4.1 fails in test_exceptions with a core dump

- `PEP 342 - Enhanced Iterators

- `A bug in pyconfig.h under Linux?

- `Dynamic class inheritance && something else

- `Weekly Python Patch/Bug Summary



This is a summary of traffic on the `python-dev mailing list`_ from
June 01, 2005 through June 15, 2005.

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developments on the list on a semi-monthly basis.  An archive_ of
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