Mailman 3 December 2006 - Python-Dev

Request for developer privileges.
by Lars Gustäbel 21 Dec '06

21 Dec '06

Hello, my name is Lars Gustäbel (SF gustaebel). I contributed tarfile.py to the Python standard library in January 2003 and have been the maintainer since then. I have provided about 25 patches over the years, most of them fixes, some of them new features and improvements. As a result, I am pretty familiar with the Python development process. If possible I would like to get developer privileges to be able to work more actively on tarfile.py for a certain time. I am currently implementing read-write POSIX.1-2001 pax format support. Development is still in progress, but it is already clear at this point, that it will be a complex change, which will definitely require some maintenance once it is finished and in day-to-day use. I would like to clean up the tarfile test suite during this process as well. The introduction of the pax format is important because it is the first tar specification that puts an end to those annoying limitations of the "original" tar format. It will become the default format for GNU tar some day. Thank you, Lars. -- Lars Gustäbel lars(a)gustaebel.de

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Listing of PEP 328 status and possible minor oversight
by Brett Cannon 20 Dec '06

20 Dec '06

I just noticed that PEP 328 (relative imports) is listed as an accepted PEP, but not completed. Is this because there is still things to do for 2.6 and 2.7? Or did someone just forget to move it to the completed PEPs section of the PEP index? If it is the former then PEP 362 will need to be moved. I also noticed that there is no mention of removing import redirection to a top-level module by having None in sys.modules. Was this for backwards-compatibility issues, or was it just not thought of? -Brett

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New Python-Ideas mailing list
by Brett Cannon 20 Dec '06

20 Dec '06

At Guido's suggestion, a new mailing list has been created named Python-Ideas (http://mail.python.org/mailman/listinfo/python-ideas). This list is meant as a place for speculative, pie-in-the-sky language design ideas to be discussed and honed to the point of practically being a PEP before being presented to python-dev or python-3000. This allows both python-dev and python-3000 to focus more on implementation work or final approval/denial of ideas instead of being flooded with long threads where people discuss ideas that are too nebulous to be considered for inclusion into Python. Like python-dev and python-3000, Python-Ideas requires you subscribe before you can post, but there is no moderator approval required. If you are interested in helping me out by being an administrator or moderator for the list, please let me know. -Brett

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Re: [Python-Dev] About dictionary lookup caching
by "Martin v. Löwis" 19 Dec '06

19 Dec '06

Raymond Hettinger schrieb: > If you can find some other design that doesn't depend on the ordering of > co_names, that would be nice; otherwise, we're adding a permanent > complication to the compiler and establishing a new invariant that would > have to be maintained by everyone hoping to generate or hack bytecodes. It wouldn't be a strict invariant, but instead, breaking it would mean that the memory consumption goes up somewhat. Regards, Martin

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About dictionary lookup caching
by Andrea Griffini 19 Dec '06

19 Dec '06

I'm experimenting with a patch for dictionary lookup caching, the main idea being avoiding the lookup of a constant (co_names) in a dictionary if the dictionary didn't change since last lookup. Currently the cache is held in a structure that is parallel to co_names (the LOAD_GLOBAL opcode uses oparg to access the cache slot) and this is wasteful if there are co_names entries that are not used for global lookups. Probably I could act at the code object creation time to sort names so that ones used by LOAD_GLOBAL are at the beginning of co_names but this would require inspecting and hacking the already generated opcode. Another case that would IMO be worth optimizing is the LOAD_ATTR lookup when it's done after a LOAD_GLOBAL (I suspect that in many cases the element being searched will be a module so caching would be simple to implement; for general objects things are way more complex and I see no simple solution for caching dictionary lookups). My opinion is that it would be by far better to do this ordering of co_names at compile time but I've no idea where to look for trying to make such a change. Can someone please point me in the right direction ? Andrea

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Open CPython VM for type information
by Kay Schluehr 17 Dec '06

17 Dec '06

Dear Python developers, while the JVM is opened to support dynamically typed languages [1] I wonder if the CPyVM could not show more openness to statically typed languages? Hereby I don't think that much about arbitrary languages for the CPyVM but sublanguages like RPython which are "static enough" to be compilable into extension modules [2]. However creating C extension modules from Python code is not really the standard way I do think Python source should be handled. Instead I think about a more direct VM support like the JVM does, that provides opcodes like iload, fstore etc. Besides this I don't expect one canonical approach for these type information to be feeded into the CPyVM. There are type inferencer like rtyper for PyPy, Psycos continous bytecode monitoring and also other approaches are possible that use type feedback. Finally optional type declarations are also an issue; however I would like to see language design discussions being separated ( -> Python 3000 ) and focus on general APIs for compiler extensions / plugs that deal with type information ( the architecture ) and VM implementation issues. Thanks, Kay [1] http://jcp.org/en/jsr/detail?id=292 [2] http://codespeak.net/pypy/dist/pypy/doc/extcompiler.html

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Weekly Python Patch/Bug Summary
by Kurt B. Kaiser 15 Dec '06

15 Dec '06

Patch / Bug Summary ___________________ Patches : 414 open ( +1) / 3498 closed ( +9) / 3912 total (+10) Bugs : 949 open ( +6) / 6376 closed (+12) / 7325 total (+18) RFE : 247 open ( +1) / 245 closed ( +1) / 492 total ( +2) New / Reopened Patches ______________________ C99 _Bool support for struct (2006-12-07) http://python.org/sf/1610575 opened by David Remahl BSD version of ctypes.util.find_library (2006-12-07) http://python.org/sf/1610795 opened by Martin Kammerhofer whitespace in `svnversion .` (2006-10-15) CLOSED http://python.org/sf/1577756 reopened by schmaller Enhanced tabbed pane widget (2006-12-10) http://python.org/sf/1612746 opened by Tal Einat encoding directive -- more examples (2006-12-11) http://python.org/sf/1613352 opened by Jim Jewett Write mode option for fileinput module. (2006-12-11) http://python.org/sf/1613500 opened by Anthony Roy POSIX capabilities support (2006-12-13) http://python.org/sf/1615158 opened by Matt Kern Creating dicts for dict subclasses (2006-12-14) http://python.org/sf/1615701 opened by Walter Dörwald BZ2File.seek() fails for large files (2006-12-14) http://python.org/sf/1615868 opened by Lars Gustäbel Cached globals+builtins lookup optimization (2006-12-15) http://python.org/sf/1616125 opened by Andrea Griffini Patches Closed ______________ whitespace in `svnversion .` (2006-10-15) http://python.org/sf/1577756 closed by gbrandl traceback on exit if syslog handler fails to initialize (2006-12-05) http://python.org/sf/1609407 closed by vsajip Race condition in os.makedirs (2006-12-04) http://python.org/sf/1608579 closed by gbrandl Prevent race condition in os.makedirs (2005-07-17) http://python.org/sf/1239890 closed by gbrandl os.makedirs - robust against partial path (2005-10-05) http://python.org/sf/1314067 closed by gbrandl modsupport does not use va_copy when available (2003-12-11) http://python.org/sf/858318 closed by sf-robot acknowledge signals in non-main threads (2004-12-21) http://python.org/sf/1088832 closed by loewis Patch for bug 999042. (2004-12-23) http://python.org/sf/1090482 closed by loewis socket leak in SocketServer (2004-12-30) http://python.org/sf/1093468 closed by loewis mailbox.py: check that os.fsync is available before using it (2006-11-19) http://python.org/sf/1599256 closed by akuchling New / Reopened Bugs ___________________ GUI for Python 2.3, 2.4, and 2.5 is very sluggish (2006-12-06) CLOSED http://python.org/sf/1610485 reopened by g4rlik cgi.py multipart/form-data (2006-12-07) http://python.org/sf/1610654 opened by Chui Tey \b in unicode regex gives strange results (2006-12-07) CLOSED http://python.org/sf/1611131 opened by akaihola os.path.exists("file/") failure on Solaris 9 (2006-12-07) http://python.org/sf/1611154 opened by Paul Eggert can't pickle NAN's in binary mode (2006-12-08) CLOSED http://python.org/sf/1611753 opened by Wayne Christopher sndhdr.what() does not recognize wav file (2006-12-09) http://python.org/sf/1611944 reopened by klankschap sndhdr.what() does not recognize wav file (2006-12-09) http://python.org/sf/1611944 opened by Floris van Manen builtin compile() doc needs PyCF_DONT_IMPLY_DEDENT (2006-12-09) http://python.org/sf/1612012 opened by Anthony Baxter Dictionary ordering docs are too unclear of dangers (2006-12-09) http://python.org/sf/1612113 opened by Calvin Spealman webchecker/urllib chokes on 404 pages (2006-12-10) CLOSED http://python.org/sf/1612729 opened by Fredrik Lundh lambda tuple parameter bus error (2006-12-11) CLOSED http://python.org/sf/1613059 opened by Bruce Cropley str.split creates new string even if pattern not found (2006-12-11) http://python.org/sf/1613130 opened by Antoine Pitrou pydoc info for a package doesn't list all package contents (2006-12-11) http://python.org/sf/1613479 opened by Nishkar Grover xmlrpclib ServerProxy uses old httplib interface (2006-12-12) http://python.org/sf/1613573 opened by Matt Brown recv_into not documented (2006-12-11) http://python.org/sf/1613651 opened by Eric Huss AttributesImpl does not implement __contains__ on Linux (2006-12-13) http://python.org/sf/1614387 opened by Jason Briggs dict throwing inaccurate KeyError on small tuple keys (2006-12-13) CLOSED http://python.org/sf/1614429 opened by toidinamai python-logging compatability with Zope. (2006-12-13) http://python.org/sf/1614460 opened by Simon Hookway tempile.TemporaryFile differences between linux and windows (2006-12-13) http://python.org/sf/1615275 opened by hirzel subprocess doesn't handle SIGPIPE (2006-12-14) http://python.org/sf/1615376 opened by Mark Diekhans IA64/AMD64/x64 confusion (2006-12-14) http://python.org/sf/1616109 opened by Sidnei da Silva Bugs Closed ___________ GUI for Python 2.3, 2.4, and 2.5 is very sluggish (2006-12-06) http://python.org/sf/1610485 closed by kbk \b in unicode regex gives strange results (2006-12-07) http://python.org/sf/1611131 deleted by akaihola can't pickle NAN's in binary mode (2006-12-08) http://python.org/sf/1611753 closed by mwh race in os.makedirs() (2005-06-18) http://python.org/sf/1223238 closed by gbrandl simple moves freeze IDLE (2006-10-05) http://python.org/sf/1571112 closed by kbk webchecker/urllib chokes on 404 pages (2006-12-10) http://python.org/sf/1612729 closed by gbrandl lambda tuple parameter bus error (2006-12-11) http://python.org/sf/1613059 closed by gbrandl logger.config problems with comma separated lists (2006-06-09) http://python.org/sf/1503765 closed by vsajip mailbox: Maildir.get_folder does not inherit factory (2006-11-20) http://python.org/sf/1600152 closed by akuchling dict throwing inaccurate KeyError on small tuple keys (2006-12-12) http://python.org/sf/1614429 closed by rhettinger New / Reopened RFE __________________ Py_DEBUG (2006-12-09) http://python.org/sf/1612190 opened by nitro Class Browser doesn't show internal classes (2006-12-09) http://python.org/sf/1612262 opened by Tal Einat RFE Closed __________ "".translate() docs should mention string.maketrans() (2006-11-08) http://python.org/sf/1592899 closed by gbrandl

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Creating dicts from dict subclasses
by Walter Dörwald 14 Dec '06

14 Dec '06

I tried to reimplement weakref.WeakValueDictionary as a subclass of dict. The test passes except for one problem: To compare results test_weakref.py converts a weakdict to a real dict via dict(weakdict). This no longer works because PyDict_Merge() does a PyDict_Check() on the argument and then ignores all overwritten methods. (The old version worked because UserDict.UserDict was used). The simplest solution is to replace the PyDict_Check() call with PyDict_CheckExact(), but this might slow things down too much, because the fallback code basically does: for key in iter(arg.keys()): self[key] = arg.__getitem__(key) Why can't we use: for key in iter(arg): self[key] = arg.__getitem__(key) instead? Servus, Walter

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Adding resume (206) support to urllib(2)
by Daniel Watkins 13 Dec '06

13 Dec '06

Hi guys, I've just been putting together a podcasting doodad and have included resuming support in it. Is this something that's already in the pipeline or should I abstract it out to urllib and submit a patch? Dan

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Re: [Python-Dev] [Python-checkins] MSI being downloaded 10x morethan all other files?!
by Terry Jones 13 Dec '06

13 Dec '06

>>>>> "Guido" == Guido van Rossum <guido(a)python.org> writes: Guido> And I just found out (after everyone else probably :-) that YouTube Guido> is almost entirely written in Python. (And now I can rub shoulders Guido> with the developers since they're all Googlers now... :-) Are any other details available? I'm mainly curious to know if they were using Twisted. Terry

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MSI being downloaded 10x more than all other files?!
by Guido van Rossum 12 Dec '06

12 Dec '06

I looked through the python.org web stats (as I usually do when preparing for a keynote) and discovered that /ftp/python/2.5/python-2.5.msi is by far the top download -- 271,971 hits, more than 5x the next one, /ftp/python/2.5/Python-2.5.tgz (47,898 hits). Are these numbers real? (The byte counts suggest they are.) What could cause this dramatic popularity of Python on Windows? Does some vendor have an auto-install hook that installs Python whenever someone opens up their new computer? Or have we just hit the jackpot? -- --Guido van Rossum (home page: http://www.python.org/~guido/)

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Re: [Python-Dev] [Python-checkins] MSI being downloaded 10x more than all other files?!
by glyph＠divmod.com 11 Dec '06

11 Dec '06

On 11:17 pm, guido(a)python.org wrote: >On 12/11/06, Jim Jewett <jimjjewett(a)gmail.com> wrote: >> On 12/8/06, Guido van Rossum <guido(a)python.org> wrote: >> > /ftp/python/2.5/python-2.5.msi is by far the top download -- 271,971 >> > hits, more than 5x the next one, /ftp/python/2.5/Python-2.5.tgz >> > (47,898 hits). Are these numbers real? >> >> Why wouldn't it be? > >Just because in the past the ratio of downloads for a particular >version was always about 70% Windows vs. 30% source. Now it seems >closer to 90/10. Personally speaking, since switching to Ubuntu, I've been so happy with the speed of releases and the quality of packaged Python that I haven't downloaded a source release from python.org in over a year. If I need packages, they're already installed. If I need source from a release, I 'apt-get source' to conveniently install it from a (very fast) ubuntu mirror. When I need something outside the Ubuntu release structure, it's typically an SVN trunk checkout, not a release tarball. I don't know what Ubuntu's impact in the general user community has been, but it seems that the vast majority of python developers I interact with on a regular basis have switched. I wouldn't be surprised if this were a major part of the impact.

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Looking for new Python-Dev Summarizers
by Steven Bethard 11 Dec '06

11 Dec '06

It's been my pleasure to write the Python-Dev Summaries for the last year and a half -- 40 summaries all told, 8 of those with Tim Lesher and 23 with Tony Meyer. It's really been an incredible learning experience, both in how the Python development process works, and in how Python as a community interacts. As I'm now coming up on the last semester of so of my Ph.D., I need to make some more time to get research done, and so I'm looking to retire from the summaries. Hence, I'm soliciting for a good replacement (or a few) who would be willing to pick up the job. The job takes a few hours about once every two weeks. I have scripts to automate most of the grunt work (e.g. collecting the threads from mail.python.org and laying out the summary as necessary for the website), so the job is pretty much just writing a ReST-formatted paragraph or two on each topic. If you've been reading Python-Dev for a while, and you'd like to get involved, this is a great place to start - I can guarantee you'll learn a lot from it. Please drop me an email if you're interested! Thanks, Steve -- I'm not *in*-sane. Indeed, I am so far *out* of sane that you appear a tiny blip on the distant coast of sanity. --- Bucky Katt, Get Fuzzy

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fileinput module tests
by Anthony Roy 09 Dec '06

09 Dec '06

Hi all, I have a patch for the fileinput.FileInput class, adding a parameter to the __init__ method called write_mode in order to specify the write mode when using the class with the inplace parameter set to True. Before I submit the patch, I've added a test to the test module, and noticed that the module is pretty messy, with half of the tests being run in the module body, and the rest in a large function body. I propose to refactor the module, moving the tests into a unittest.TestCase subclass (essentially unchanged, bar changing verify calls to self.assert_ calls, raise TestFailed(...) to self.fail(...) etc). I think this will add clarity and modularity to the tests, and bring them into line with the unittest based test suite used by the test_file module amongst others (which I'm guessing are substantially more up to date than test_fileinput). Any thought? Cheers, -- Ant...

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Windows SDK
by Albert Strasheim 09 Dec '06

09 Dec '06

Hello all (A quick google of the python-dev archive didn't turn up any discussions on this topic. If this has already been discussed, please accept my humble apologies.) As part of the Windows Vista release, Microsoft have created the "Windows SDK" that looks like Platform SDK on steroids. It includes 32-bit and 64-bit libraries and compilers, debugging tools, etc. and supports Windows XP, Windows Server 2003 and Windows Vista. Check the Microsoft Windows SDK Blog for more info: http://blogs.msdn.com/windowssdk/ Go here for links to ISO and web install: http://blogs.msdn.com/windowssdk/archive/2006/11/08/windows-sdk-for-windows… I'm only guessing here, but I think the Windows SDK is probably going to become the de facto standard for building software on Windows in the absence of Visual Studio. Has anybody else looked at the Windows SDK yet? Any thoughts on what needs to be done with distutils so that the Windows SDK can be supported in Python 2.6? Cheers, Albert Strasheim

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help for a noob - version for a sharp ARM
by David Boddie 09 Dec '06

09 Dec '06

On Fri Dec 8 08:07:16 CET 2006, Josiah Carlson wrote: > a Fred <fghaibach at comcast.net> wrote: > > > > I'm looking for advice on stripping down Python for an SBC to run Numpy > > and Scipy. I have the following notes on the system > > > > We have code that requires recent versions of Numpy and Scipy. > > The processor is a 32 bit Sharp ARM Sharp LH7A404 32 bit ARM922TDMI with > > 32MB of SDRAM. > > 512 MB flash disk - but 400 MB is reserved for data > > The OS is Linux > > only a tty interface is used. > > > > Does anyone have a feel as to whether Python for Arm is the correct > > starting point? > > Sounds like plenty of muscle to handle Python certain domain number > crunching problems. It appears that this ARM variant doesn't have a floating point coprocessor. http://www.sharpsma.com/Page.aspx/americas/en/part/LH7A404/ I hope we're dealing with those problem domains here. ;-) > > What modules can I safely add/strip out? > > Most every C module you don't need. You can also compile without > unicode. I believe you can more or less toss everything except for the > base python binary and the pythonxy.so (or pythonxy.dll) for your > platform, but I am most likely wrong. I found that Python tries to import various modules when it starts up, so you might want to be a bit conservative with the ones you discard. However, if the target platform doesn't have libraries that various extension modules require then there's clearly no point in deploying those extensions. There are lots of irrelevant modules (for your application, at least) in the standard library. Anything that's platform-specific can go, apart from any Linux-specific modules, obviously, and even those might be unnecessary. I'm not sure if it's possible to automatically strip out Tkinter (lib-tk) and IDLE (idlelib), but it's probably worth doing so in your case. I should return to my own experiments and do all that again in a systematic way, just to see what can be removed. > My (awful) suggestion: start with > a Python installation in some user path, like ~/python . Toss > everything and start adding things that it complains about until it > starts working again. Or there's that approach. A module dependency graph would be useful to have, or even just a list of modules that are required to get to the interactive prompt. It might also be worthwhile compiling all the pure Python modules to bytecode and discarding the sources, but only if the compiled code is smaller, of course. > > Will Python take more than 5-6 seconds to load? > > I have previously gotten dos versions of Python (I think 1.5 or 1.4) to > load on a 486 sx 33 with 8 megs of ram in a couple seconds. You > shouldn't have issues with startup on an ARM. Less than a second, I would imagine. Extension modules will also increase the loading time, especially if they need to be perform some tasks when they start. > > Will old Python releases, like 1.5.x, work with newer Numpy and Scipy? > > I don't know. But you should be able to remove unused portions of > Python for your platform. There are somewhat recent posts in this > mailing lists about embedded systems and Python. Others may be able to > help you more. It should be possible to compile a version of Python for the ARM922TDMI that uses Thumb instructions. These are 16 bit instructions that are expanded on the fly so that they can be processed by the CPU as normal 32 bit wide instructions. This doesn't mean that the resulting executable and libraries will be half the size that they would have been when compiled normally, but you may be able to save some storage space that way. I have no idea whether this trick will help you save RAM as well. David

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Re: [Python-Dev] [Python-checkins] MSI being downloaded 10x more than all otherfiles?!
by "Martin v. Löwis" 08 Dec '06

08 Dec '06

Terry Reedy schrieb: > How do the first two months downloads of 2.5.msi compare to 2.4.msi? It's actually publicly available: http://www.python.org/webstats/ Regards, Martin

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Re: [Python-Dev] [Python-checkins] MSI being downloaded 10x more than all otherfiles?!
by Guido van Rossum 08 Dec '06

08 Dec '06

That was the month of October. If people believe these numbers are real, we're doing great!!! On 12/8/06, Fredrik Lundh <fredrik(a)pythonware.com> wrote: > Guido van Rossum wrote: > > >I looked through the python.org web stats (as I usually do when > > preparing for a keynote) and discovered that > > /ftp/python/2.5/python-2.5.msi is by far the top download -- 271,971 > > hits, more than 5x the next one, /ftp/python/2.5/Python-2.5.tgz > > (47,898 hits). > > over what period ? > > fwiw, I've seen a 2.5x ratio for my stuff over the last year; I've always assumed > that most people on other platforms are simply getting their stuff from the vendor's > standard repository. > > </F> > > > > _______________________________________________ > Python-checkins mailing list > Python-checkins(a)python.org > http://mail.python.org/mailman/listinfo/python-checkins > -- --Guido van Rossum (home page: http://www.python.org/~guido/)

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a feature i'd like to see in python #2: indexing of match objects
by Ben Wing 08 Dec '06

08 Dec '06

this one is fairly simple. if `m' is a match object, i'd like to be able to write m[1] instead of m.group(1). (similarly, m[:] should return the same as list(m.groups()).) this would remove some of the verbosity of regexp code, with probably a net gain in readability; certainly no loss. ben

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help for a noob - version for a sharp ARM
by a Fred 08 Dec '06

08 Dec '06

I'm looking for advice on stripping down Python for an SBC to run Numpy and Scipy. I have the following notes on the system We have code that requires recent versions of Numpy and Scipy. The processor is a 32 bit Sharp ARM Sharp LH7A404 32 bit ARM922TDMI with 32MB of SDRAM. 512 MB flash disk - but 400 MB is reserved for data The OS is Linux only a tty interface is used. Does anyone have a feel as to whether Python for Arm is the correct starting point? What modules can I safely add/strip out? Will Python take more than 5-6 seconds to load? Will old Python releases, like 1.5.x, work with newer Numpy and Scipy? Thanks! a Fred

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Re: [Python-Dev] Spam and semi-spam and neo-spam
by Kurt B. Kaiser 08 Dec '06

08 Dec '06

"Karen Treanor" <krwtreanor(a)ozemail.com.au> writes: > More and more people seem to be having a selection of email addresses, > some for general contact, some for business, and one private one for > only a select few contacts. This isn't possible in business, as your > email address is by necessity public, it has to be. > > I recently tried replying to a piece of spam and clicked on the opt > out button, but the sent item just bounced back as undeliverable. > Yahoo has a Spam tag facility but that only works for 'fixed' sites, > these random rotating ones each come in as discreet items and there's > no way to block them at source. Don't ever do that! 1. The majority of these links are bogus. 2. The majority of the rest use your click to verify you are a working email address. Then they sell the 'verified' list and you get even more spam. 3. Some of the links are fraudulent: they are phishing links which don't go where you expect, i.e. they use special characters to fool you. The result is you are directed to a site which infects your computer. -- KBK

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Re: [Python-Dev] RealClearPolitics - Articles - Exit Rumsfeld, Smiling
by Kurt B. Kaiser 08 Dec '06

08 Dec '06

"Karen Treanor" <krwtreanor(a)ozemail.com.au> writes: > Unfortunately this won't work for me, not by clicking on it or by > cutting and pasting it. The url below is wrapped, I assume you fixed the wrap? > > -----Original Message----- From: Kurt B. Kaiser [mailto:kbk@shore.net] >Sent: Friday, 8 December 2006 4:57 AM To: cwkaiser(a)fastmail.fm; Karen >Treanor Subject: RealClearPolitics - Articles - Exit Rumsfeld, Smiling > > <URL: > http://www.realclearpolitics.com/articles/2006/12/exit_rumsfeld_smilin > g.html >> -- KBK

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Threading, atexit, and logging
by "Martin v. Löwis" 07 Dec '06

07 Dec '06

In bug #1566280 somebody reported that he gets an exception where the logging module tries to write to closed file descriptor. Upon investigation, it turns out that the file descriptor is closed because the logging atexit handler is invoked. This is surprising, as the program is far from exiting at this point. Investigating further, I found that the logging atexit handler is registered *after* the threading atexit handler, so it gets invoked *before* the threading's atexit. Now, threading's atexit is the one that keeps the application running, by waiting for all non-daemon threads to shut down. As this application does all its work in non-daemon threads, it keeps running for quite a while - except that the logging module gives errors. The real problem here is that atexit handlers are invoked even though the program logically doesn't exit, yet (it's not just that the threading atexit is invoked after logging atexit - this could happen to any atexit handler that gets registered). I added a patch to this report which makes the MainThread __exitfunc a sys.exitfunc, chaining what is there already. This will work fine for atexit (as atexit is still imported explicitly to register its sys.exitfunc), but it might break if other applications still insist on installing a sys.exitfunc. What do you think about this approach? Regards, Martin P.S. There is another issue reported about the interpreter crashing; I haven't been able to reproduce this, yet.

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features i'd like [Python 3000?] ... #4: interpolated strings ala perl
by Ben Wing 07 Dec '06

07 Dec '06

sorry to be casting multiple ideas at once to the list. i've been looking into other languages recently and reading the recent PEP's and such and it's helped crystallize ideas about what could be better about python. i see in PEP 3101 that there's some work going on to fix up the string formatting capabilities of python. it looks good to me but it still doesn't really address the lack of a simple interpolated string mechanism, as in perl or ruby. i find myself constantly writing stuff like text="Family: %s" % self.name maybe_errout("%s, line %s: %s\n" % (title, lineno, errstr)) def __str__(self): return "CCGFeatval(%s, parents=%s, licensing=%s)" % ( (self.name, self.parents, self.licensing)) and lots of similar examples that are just crying out for perl-style variable interpolation. the proposals in PEP 3101 don't help much; i'd get instead something like maybe_errout("{0}, line {1}: {2}\n".format(title, lineno, errstr)) which isn't any better than the current % notation, or something like maybe_errout("{title}, line {lineno}: {errstr}\n".format(title=title, lineno=lineno, errstr=errstr)) where i have to repeat each interpolated variable three times. yuck yuck yuck. how about something nice like maybe_errout(i"[title], line [lineno]: [errstr]\n") or (with the first example above) text=i"Family: [self.name]" or (third example above) def __str__(self): return i"CCGFeatval([self.name], parents=[self.parents], licensing=[self.licensing])" the advantage of these is the same as for all such interpolations: the interpolated variable is logically placed exactly where it will be substituted, rather than somewhere else, with the brain needing to do some additional cross-referencing. `i' in front of a string indicates an "interpolated" string just like `r' in the same position means "raw string". if you think this is too invisible, you could maybe use `in' or something easier to see. however, i could see a case being made for combining both `i' and `r' on the same string, and so using a single letter seems to make the most sense. formatting params can follow, e.g. print i"The value of [stock[x]] is [stockval[x]:%6.2f]" some comments: 1. i suggest brackets here so as to parallel but not interfere with PEP 3101, which uses braces; PEP 3101 is somewhat orthogonal to this proposal and the two might want to coexist. i think using something like brackets or braces is better than perl's $ convention (it explicitly indicates the boundaries of the interpolation) and simpler than ruby's #{...} or make's ${...}; since strings are only interpolated if you specifically indicate this, there's less need to use funny characters to avoid accidental interpolation. 2. as shown in the last example, format specifiers can be added to an interpolation, as in PEP 3101. maybe the % is unnecessary. 3. as shown in various examples, things other than just straight variables can be interpolated. the above examples include array/hash references and object attributes. it's not exactly clear what should and shouldn't be allowed. one possibility is just to allow an arbitrary expression. PEP 3101 isn't going to do this because it's working on existing strings (including ones that may come from the user), and so allowing arbitrary expressions could lead to security holes. but here, we're talking about immediate strings, so security holes of this sort should not a concern. 4. the semantics of an interpolated string are exactly that of a series of string concatenations, e.g. return i"CCGFeatval([self.name], parents=[self.parents], licensing=[self.licensing])" is equivalent to return "CCGFeatval(" + self.name + ", parents=" + self.parents + ", licensing=" + self.licensing + ")" ben

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Adding C99 bool to struct module
by "Martin v. Löwis" 07 Dec '06

07 Dec '06

#1610575 suggests to introduce the 't' code to support the _Bool type where available, and uses char if it isn't available. Any objections to adding it? Regards, Martin

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