Mailman 3 July 2007 - Python-Dev

Re: [Python-Dev] proposed attribute lookup optimization
by Paul Pogonyshev July 12, 2007

July 12, 2007

[I don't know why I didn't receive this mail, presumably spam filter at gmx.net sucks as always] Phillip J. Eby wrote: > At 08:23 PM 7/8/2007 +0300, Paul Pogonyshev wrote: > >I would like to propose an optimization (I think so, anyway) for the > >way attributes are looked up. [...] > > [...] > > Again, though, this has already been proposed, and I believe there's > a patch awaiting review for inclusion in 2.6 (and presumably 3.0). OK, good to know. Of course … [View More]

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itertools addition: getitem()
by Walter Dörwald July 11, 2007

July 11, 2007

I'd like to propose the following addition to itertools: A function itertools.getitem() which is basically equivalent to the following python code: _default = object() def getitem(iterable, index, default=_default): try: return list(iterable)[index] except IndexError: if default is _default: raise return default but without materializing the complete list. Negative indexes are supported too (this requires additional temporary storage for abs(index) … [View More]

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Add a -z interpreter flag to execute a zip file
by Andy C July 11, 2007

July 11, 2007

I'd like to request comments on this patch I submitted: https://sourceforge.net/tracker/index.php?func=detail&aid=1739468&group_id=… There are many details given in the comments on that page. This can be used to deploy Python programs in a very lightweight and cross-platform way. You could imagine a cgi script or a light web app server being deployed like this. I have personally deployed Python programs using zip files and this would get rid of the need for boilerplate needed for … [View More]

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Should r53624 be applied to release branches?
by Aaron Bingham July 10, 2007

July 10, 2007

Hello, We recently had a production failure caused by the issue fixed in r53624 on the trunk [1]. I see that this patch has also been applied to py3k-struni. Should this patch be merged to the release branches? In the meantime we will have to patch subprocess.py ourselves. [1] http://mail.python.org/pipermail/python-checkins/2007-February/058421.html Thanks, -- Aaron Bingham Senior Software Engineer bingham(a)cenix-bioscience.com Tel. +49 (0)351 4173-146 Fax +49 (0)351 4173-109 … [View More]

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Weekly Python Patch/Bug Summary
by Kurt B. Kaiser July 10, 2007

July 10, 2007

Patch / Bug Summary ___________________ Patches : 392 open ( +7) / 3792 closed ( +2) / 4184 total ( +9) Bugs : 1042 open (+13) / 6757 closed (+13) / 7799 total (+26) RFE : 263 open ( +1) / 292 closed ( +1) / 555 total ( +2) New / Reopened Patches ______________________ "%d" format handling for long values (2007-06-25) http://python.org/sf/1742669 opened by Gabriel Genellina Read Write lock (2007-06-27) http://python.org/sf/1744382 opened by Yaakov Nemoy … [View More]

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Summary of Tracker Issues
by Tracker July 9, 2007

July 9, 2007

ACTIVITY SUMMARY (07/01/07 - 07/08/07) Tracker at http://bugs.python.org/ To view or respond to any of the issues listed below, click on the issue number. Do NOT respond to this message. 1645 open ( +0) / 8584 closed ( +0) / 10229 total ( +0) Average duration of open issues: 850 days. Median duration of open issues: 798 days. Open Issues Breakdown open 1645 ( +0) pending 0 ( +0)

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proposed attribute lookup optimization
by Paul Pogonyshev July 9, 2007

July 9, 2007

Hi, I would like to propose an optimization (I think so, anyway) for the way attributes are looked up. Currently, it is done like this: return value of attribute in instance.__dict__ if present for type in instance.__class__.__mro__: return value of attribute in type.__dict__ if present raise AttributeError I propose adding to each type a C-implementation-private dictionary of attribute-name => type-in-which-defined. Then, it will not be necessary to traverse __mro__ on each … [View More]attribute lookup for names which are present in this lookup dictionary. This optimization will not have any effect for attributes defined on instance. It will, however, for type attributes, most notably for methods. It will most likely cause a slowdown for looking up attributes that are defined directly on self.__class__, not on any of its bases. However, I believe it will be a benefit for all non-extremely shallow inheritance tree. Especially if they involve multiple inheritance. One open question is what to do in case an attribute on a type is set or deleted. Python example: class Current (type): @staticmethod def getattribute (self, name): dict = object.__getattribute__(self, '__dict__') if name in dict: return dict[name] mro = object.__getattribute__ (self, '__class__').__mro__ for type in mro: dict = type.__dict__ if name in dict: return dict[name] raise AttributeError def __init__(self, name, bases, dict): super (Current, self).__init__(name, bases, dict) self.__getattribute__ = Current.getattribute class Optimized (type): @staticmethod def getattribute (self, name): dict = object.__getattribute__(self, '__dict__') if name in dict: return dict[name] # <possible optimization> lookup = object.__getattribute__ (self, '__class__').__lookup_cache__ if name in lookup: return lookup[name].__dict__[name] # </possible optimization> mro = object.__getattribute__ (self, '__class__').__mro__ for type in mro: dict = object.__getattribute__(type, '__dict__') if name in dict: return dict[name] raise AttributeError # <possible optimization> def build_lookup_cache (self): lookup = {} for type in self.__mro__: for name in type.__dict__: if name not in lookup: lookup[name] = type return lookup # </possible optimization> def __init__(self, name, bases, dict): super (Optimized, self).__init__(name, bases, dict) # <possible optimization> self.__lookup_cache__ = self.build_lookup_cache () # </possible optimization> self.__getattribute__ = Optimized.getattribute class A (object): __metaclass__ = Optimized x = 1 class B (A): pass class C (B): pass class D (C): pass class E (D): pass t = E () for k in xrange (100000): t.x Try swapping metaclass of A from Optimized to Current and measure execution time. Paul [View Less]

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Python for embedding?
by "Knut A. Wikström" July 8, 2007

July 8, 2007

Python is a great language. We all know. But I have tried implementing Python into C/C++ applications, and have a) had a lot of trouble getting it running properly and b) it is slow, compared to other languages, like LUA. What is my idea, is to make a Python implementation made to be embedded into applications.. It will have these features: a) Small footprint. b) Easy-to-use, but still advanced API. c) Stackless. d) A smaller standard library. e) Fast. The smaller footprint is, so that it … [View More]

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Python 2.6 BaseException.message deprecation, really needed?
by Gustavo Carneiro July 8, 2007

July 8, 2007

In PyGObject we want to use a 'message' attribute in an exception defined by us. The name 'message' comes from a C API, therefore we would like to keep it for easier mapping between C and Python APIs. Why does Python have to deprecate this attribute? .../gobject/option.py:187: DeprecationWarning: BaseException.message has been deprecated as of Python 2.6 gerror.message = str(error) -- Gustavo J. A. M. Carneiro INESC Porto, Telecommunications and Multimedia Unit "The universe is always … [View More]

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Adding NetworkIOError for bug 1706815
by Gregory P. Smith July 7, 2007

July 7, 2007

In response to bug 1706815 and seeing messy code to catch errors in network apps I've implemented most of the ideas in the bug and added a NetworkIOError exception (child of IOError). With this, socket.error would now inherit from NetworkIOError instead of being its own thing (the old one didn't even declare a parent!). Complete patch attached to the bug. All unit tests pass. Documentation updates included. http://sourceforge.net/tracker/index.php?func=detail&aid=1706816&group_id=5…… [View More]

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