Mailman 3 December 2012 - Python-Dev

Re: [Python-Dev] cpython: Issue #16049: add abc.ABC helper class.
by Georg Brandl 16 Dec '12

16 Dec '12

Am 13.12.2012 18:09, schrieb andrew.svetlov: > http://hg.python.org/cpython/rev/9347869d1066 > changeset: 80840:9347869d1066 > user: Andrew Svetlov <andrew.svetlov(a)gmail.com> > date: Thu Dec 13 19:09:33 2012 +0200 > summary: > Issue #16049: add abc.ABC helper class. > > Patch by Bruno Dupuis. > > files: > Doc/library/abc.rst | 18 ++++++++++++++---- > Lib/abc.py | 6 ++++++ > Lib/test/test_abc.py | 13 +++++++++++++ > Misc/NEWS | 3 +++ > 4 files changed, 36 insertions(+), 4 deletions(-) > > > diff --git a/Doc/library/abc.rst b/Doc/library/abc.rst > --- a/Doc/library/abc.rst > +++ b/Doc/library/abc.rst > @@ -12,9 +12,9 @@ > -------------- > > This module provides the infrastructure for defining :term:`abstract base > -classes <abstract base class>` (ABCs) in Python, as outlined in :pep:`3119`; see the PEP for why this > -was added to Python. (See also :pep:`3141` and the :mod:`numbers` module > -regarding a type hierarchy for numbers based on ABCs.) > +classes <abstract base class>` (ABCs) in Python, as outlined in :pep:`3119`; > +see the PEP for why this was added to Python. (See also :pep:`3141` and the > +:mod:`numbers` module regarding a type hierarchy for numbers based on ABCs.) > > The :mod:`collections` module has some concrete classes that derive from > ABCs; these can, of course, be further derived. In addition the > @@ -23,7 +23,7 @@ > hashable or a mapping. > > > -This module provides the following class: > +This module provides the following classes: > > .. class:: ABCMeta > > @@ -127,6 +127,16 @@ > available as a method of ``Foo``, so it is provided separately. > > > +.. class:: ABC > + > + A helper class that has :class:`ABCMeta` as metaclass. :class:`ABC` is the > + standard class to inherit from in order to create an abstract base class, > + avoiding sometimes confusing metaclass usage. > + > + Note that :class:`ABC` type is still :class:`ABCMeta`, therefore inheriting > + from :class:`ABC` requires usual precautions regarding metaclasses usage > + as multiple inheritance may lead to metaclass conflicts. > + Needs a versionadded. Georg

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Is is worth disentangling distutils?
by Antonio Cavallo 15 Dec '12

15 Dec '12

Hi, I wonder if is it worth/if there is any interest in trying to "clean" up distutils: nothing in terms to add new features, just a *major* cleanup retaining the exact same interface. I'm not planning anything like *adding features* or rewriting rpm/rpmbuild here, simply cleaning up that un-holy code mess. Yes it served well, don't get me wrong, and I think it did work much better than anything it was meant to replace it. I'm not into the py3 at all so I wonder how possibly it could fit/collide into the big plan. Or I'll be wasting my time? Thanks

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Downloads page: Which version of Python should be listed first?
by Chris Angelico 15 Dec '12

15 Dec '12

The default version shown on http://docs.python.org/ is now 3.3.0, which I think is a Good Thing. However, http://python.org/download/ puts 2.7 first, and says: """If you don't know which version to use, start with Python 2.7; more existing third party software is compatible with Python 2 than Python 3 right now.""" Firstly, is this still true? (I wouldn't have a clue.) And secondly, would this be better worded as "one's better but the other's a good fall-back"? Something like: """Don't know which version to use? Python 3.3 is the recommended version for new projects, but much existing software is compatible with Python 2.""" I only ever send people there to learn about programming, not to get a dependency for an existing codebase, so I don't know what is actually used. ChrisA

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Summary of Python tracker Issues
by Python tracker 14 Dec '12

14 Dec '12

ACTIVITY SUMMARY (2012-12-07 - 2012-12-14) Python tracker at http://bugs.python.org/ To view or respond to any of the issues listed below, click on the issue. Do NOT respond to this message. Issues counts and deltas: open 3826 (+10) closed 24631 (+34) total 28457 (+44) Open issues with patches: 1683 Issues opened (37) ================== #16421: importlib.machinery.ExtensionFileLoader cannot load several mo http://bugs.python.org/issue16421 reopened by haypo #16637: py-bt, py-locals, etc. GDB commands fail with output-radix 16 http://bugs.python.org/issue16637 opened by mshroyer #16638: support multi-line docstring signatures in IDLE calltips http://bugs.python.org/issue16638 opened by chris.jerdonek #16640: Less code under lock in sched.scheduler http://bugs.python.org/issue16640 opened by serhiy.storchaka #16641: sched.scheduler.enter arguments should not be modifiable http://bugs.python.org/issue16641 opened by serhiy.storchaka #16642: Mention new "kwargs" named tuple parameter in sched module http://bugs.python.org/issue16642 opened by serhiy.storchaka #16643: Wrong documented default value for timefunc parameter in sched http://bugs.python.org/issue16643 opened by serhiy.storchaka #16644: Wrong code in ContextManagerTests.test_invalid_args() in test_ http://bugs.python.org/issue16644 opened by serhiy.storchaka #16645: Wrong test_extract_hardlink() in test_tarfile.py http://bugs.python.org/issue16645 opened by serhiy.storchaka #16646: FTP.makeport() loses socket error details http://bugs.python.org/issue16646 opened by serhiy.storchaka #16647: LMTP.connect() loses socket error details http://bugs.python.org/issue16647 opened by serhiy.storchaka #16648: stdib should use new exception types from PEP 3151 http://bugs.python.org/issue16648 opened by asvetlov #16649: Add a PyCF_DISPLAY_EXPRESSION_RESULTS flag http://bugs.python.org/issue16649 opened by ncoghlan #16650: Popen._internal_poll() references errno.ECHILD outside of the http://bugs.python.org/issue16650 opened by serhiy.storchaka #16651: Find out what stdlib modules lack a pure Python implementation http://bugs.python.org/issue16651 opened by brett.cannon #16652: socket.getfqdn docs are not explicit enough about the algorith http://bugs.python.org/issue16652 opened by r.david.murray #16653: reference kept in f_locals prevents the tracing/profiling of a http://bugs.python.org/issue16653 opened by xdegaye #16655: IDLE list.append calltips test failures http://bugs.python.org/issue16655 opened by chris.jerdonek #16656: os.walk ignores international dirs on Windows http://bugs.python.org/issue16656 opened by techtonik #16657: traceback.format_tb incorrect docsting http://bugs.python.org/issue16657 opened by mgedmin #16658: Missing "return" in HTTPConnection.send() http://bugs.python.org/issue16658 opened by amaury.forgeotdarc #16659: Pure Python implementation of random http://bugs.python.org/issue16659 opened by serhiy.storchaka #16661: test_posix.test_getgrouplist fails on some systems - incorrect http://bugs.python.org/issue16661 opened by gregory.p.smith #16662: load_tests not invoked in package/__init__.py http://bugs.python.org/issue16662 opened by rbcollins #16663: Poor documentation for METH_KEYWORDS http://bugs.python.org/issue16663 opened by r3m0t #16664: [PATCH] Test Glob: files starting with . http://bugs.python.org/issue16664 opened by Sebastian.Kreft #16665: doc for builtin hex() is poor http://bugs.python.org/issue16665 opened by rurpy2 #16666: docs wrongly imply socket.getaddrinfo takes keyword arguments http://bugs.python.org/issue16666 opened by Mikel.Ward #16667: timezone docs need "versionadded: 3.2" http://bugs.python.org/issue16667 opened by ncoghlan #16669: Docstrings for namedtuple http://bugs.python.org/issue16669 opened by serhiy.storchaka #16670: Point class may be not be a good example for namedtuple http://bugs.python.org/issue16670 opened by julien.tayon #16672: improve tracing performances when f_trace is NULL http://bugs.python.org/issue16672 opened by xdegaye #16674: Faster getrandbits() for small integers http://bugs.python.org/issue16674 opened by serhiy.storchaka #16676: Segfault under Python 3.3 after PyType_GenericNew http://bugs.python.org/issue16676 opened by tseaver #16677: Hard to find operator precedence in Lang Ref. http://bugs.python.org/issue16677 opened by rurpy2 #16678: optparse: parse only known options http://bugs.python.org/issue16678 opened by techtonik #16679: Wrong URL path decoding http://bugs.python.org/issue16679 opened by claudep Most recent 15 issues with no replies (15) ========================================== #16677: Hard to find operator precedence in Lang Ref. http://bugs.python.org/issue16677 #16676: Segfault under Python 3.3 after PyType_GenericNew http://bugs.python.org/issue16676 #16674: Faster getrandbits() for small integers http://bugs.python.org/issue16674 #16663: Poor documentation for METH_KEYWORDS http://bugs.python.org/issue16663 #16658: Missing "return" in HTTPConnection.send() http://bugs.python.org/issue16658 #16657: traceback.format_tb incorrect docsting http://bugs.python.org/issue16657 #16655: IDLE list.append calltips test failures http://bugs.python.org/issue16655 #16652: socket.getfqdn docs are not explicit enough about the algorith http://bugs.python.org/issue16652 #16646: FTP.makeport() loses socket error details http://bugs.python.org/issue16646 #16645: Wrong test_extract_hardlink() in test_tarfile.py http://bugs.python.org/issue16645 #16643: Wrong documented default value for timefunc parameter in sched http://bugs.python.org/issue16643 #16642: Mention new "kwargs" named tuple parameter in sched module http://bugs.python.org/issue16642 #16640: Less code under lock in sched.scheduler http://bugs.python.org/issue16640 #16626: Infinite recursion in glob.glob('*:') on Windows http://bugs.python.org/issue16626 #16623: argparse help formatter does not honor non-breaking space http://bugs.python.org/issue16623 Most recent 15 issues waiting for review (15) ============================================= #16679: Wrong URL path decoding http://bugs.python.org/issue16679 #16674: Faster getrandbits() for small integers http://bugs.python.org/issue16674 #16672: improve tracing performances when f_trace is NULL http://bugs.python.org/issue16672 #16669: Docstrings for namedtuple http://bugs.python.org/issue16669 #16667: timezone docs need "versionadded: 3.2" http://bugs.python.org/issue16667 #16664: [PATCH] Test Glob: files starting with . http://bugs.python.org/issue16664 #16659: Pure Python implementation of random http://bugs.python.org/issue16659 #16657: traceback.format_tb incorrect docsting http://bugs.python.org/issue16657 #16653: reference kept in f_locals prevents the tracing/profiling of a http://bugs.python.org/issue16653 #16650: Popen._internal_poll() references errno.ECHILD outside of the http://bugs.python.org/issue16650 #16647: LMTP.connect() loses socket error details http://bugs.python.org/issue16647 #16646: FTP.makeport() loses socket error details http://bugs.python.org/issue16646 #16645: Wrong test_extract_hardlink() in test_tarfile.py http://bugs.python.org/issue16645 #16644: Wrong code in ContextManagerTests.test_invalid_args() in test_ http://bugs.python.org/issue16644 #16642: Mention new "kwargs" named tuple parameter in sched module http://bugs.python.org/issue16642 Top 10 most discussed issues (10) ================================= #16612: Integrate "Argument Clinic" specialized preprocessor into CPyt http://bugs.python.org/issue16612 21 msgs #16656: os.walk ignores international dirs on Windows http://bugs.python.org/issue16656 21 msgs #16651: Find out what stdlib modules lack a pure Python implementation http://bugs.python.org/issue16651 17 msgs #15207: mimetypes.read_windows_registry() uses the wrong regkey, creat http://bugs.python.org/issue15207 9 msgs #14894: distutils.LooseVersion fails to compare number and a word http://bugs.python.org/issue14894 7 msgs #16659: Pure Python implementation of random http://bugs.python.org/issue16659 7 msgs #16661: test_posix.test_getgrouplist fails on some systems - incorrect http://bugs.python.org/issue16661 6 msgs #16666: docs wrongly imply socket.getaddrinfo takes keyword arguments http://bugs.python.org/issue16666 6 msgs #7741: Allow multiple statements in code.InteractiveConsole.push http://bugs.python.org/issue7741 5 msgs #16665: doc for builtin hex() is poor http://bugs.python.org/issue16665 5 msgs Issues closed (32) ================== #7719: distutils: ignore .nfsXXXX files http://bugs.python.org/issue7719 closed by eric.araujo #11797: 2to3 does not correct "reload" http://bugs.python.org/issue11797 closed by python-dev #12446: StreamReader Readlines behavior odd http://bugs.python.org/issue12446 closed by serhiy.storchaka #13091: ctypes: memory leak http://bugs.python.org/issue13091 closed by pitrou #13390: Hunt memory allocations in addition to reference leaks http://bugs.python.org/issue13390 closed by pitrou #13512: ~/.pypirc created insecurely http://bugs.python.org/issue13512 closed by eric.araujo #13614: setup.py register fails if long_description contains ReST http://bugs.python.org/issue13614 closed by eric.araujo #14475: codecs.StreamReader.read behaves differently from regular file http://bugs.python.org/issue14475 closed by serhiy.storchaka #15209: Re-raising exceptions from an expression http://bugs.python.org/issue15209 closed by ncoghlan #15526: test_startfile crash on Windows 7 AMD64 http://bugs.python.org/issue15526 closed by sbt #15872: shutil.rmtree(..., ignore_errors=True) doesn't ignore all erro http://bugs.python.org/issue15872 closed by hynek #16049: Create abstract base classes by inheritance rather than a dire http://bugs.python.org/issue16049 closed by asvetlov #16267: order of decorators @abstractmethod and @classmethod is signif http://bugs.python.org/issue16267 closed by ncoghlan #16495: bytes_decode() unnecessarily examines encoding http://bugs.python.org/issue16495 closed by chris.jerdonek #16582: Tkinter calls SystemExit with string http://bugs.python.org/issue16582 closed by asvetlov #16598: Docs: double newlines printed in some file iteration examples http://bugs.python.org/issue16598 closed by asvetlov #16602: weakref can return an object with 0 refcount http://bugs.python.org/issue16602 closed by pitrou #16614: argparse should have an option to require un-abbreviated optio http://bugs.python.org/issue16614 closed by terry.reedy #16616: test_poll.PollTests.poll_unit_tests() is dead code http://bugs.python.org/issue16616 closed by sbt #16628: leak in ctypes.resize() http://bugs.python.org/issue16628 closed by pitrou #16629: IDLE: Calltips test fails due to int docstring change http://bugs.python.org/issue16629 closed by chris.jerdonek #16634: urllib.error.HTTPError.reason is not documented http://bugs.python.org/issue16634 closed by orsenthil #16636: codecs: readline() followed by readlines() returns trunkated r http://bugs.python.org/issue16636 closed by serhiy.storchaka #16639: not your all issuse send http://bugs.python.org/issue16639 closed by rosslagerwall #16654: IDLE problems with Mac OS 10.6.8 ("print syntax") http://bugs.python.org/issue16654 closed by r.david.murray #16660: Segmentation fault when importing hashlib http://bugs.python.org/issue16660 closed by gregory.p.smith #16668: Remove python3dll.vcxproj from pcbuild.sln http://bugs.python.org/issue16668 closed by loewis #16671: logging.handlers.QueueListener sentinel should not be None http://bugs.python.org/issue16671 closed by vinay.sajip #16673: Corrections in the library OS (PEP8) http://bugs.python.org/issue16673 closed by ezio.melotti #16675: Ship Python with a package manager http://bugs.python.org/issue16675 closed by r.david.murray #16680: Line buffering in socket._fileobject is broken http://bugs.python.org/issue16680 closed by neologix #1748064: inspect.getargspec fails on built-in or slot wrapper methods http://bugs.python.org/issue1748064 closed by asvetlov

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Re: [Python-Dev] cpython: Using 'long double' to force this structure to be worst case aligned is no
by Antoine Pitrou 14 Dec '12

14 Dec '12

On Tue, 11 Dec 2012 03:05:19 +0100 (CET) gregory.p.smith <python-checkins(a)python.org> wrote: > Using 'long double' to force this structure to be worst case aligned is no > longer required as of Python 2.5+ when the gc_refs changed from an int (4 > bytes) to a Py_ssize_t (8 bytes) as the minimum size is 16 bytes. > > The use of a 'long double' triggered a warning by Clang trunk's > Undefined-Behavior Sanitizer as on many platforms a long double requires > 16-byte alignment but the Python memory allocator only guarantees 8 byte > alignment. > > So our code would allocate and use these structures with technically improper > alignment. Though it didn't matter since the 'dummy' field is never used. > This silences that warning. > > Spelunking into code history, the double was added in 2001 to force better > alignment on some platforms and changed to a long double in 2002 to appease > Tru64. That issue should no loner be present since the upgrade from int to > Py_ssize_t where the minimum structure size increased to 16 (unless anyone > knows of a platform where ssize_t is 4 bytes?) What?? Every 32-bit platform has a 4 bytes ssize_t (and size_t). > We can probably get rid of the double and this union hack all together today. > That is a slightly more invasive change that can be left for later. How do you suggest to get rid of it? Some platforms still have strict alignment rules and we must enforce that PyObjects (*) are always aligned to the largest possible alignment, since a PyObject-derived struct can hold arbitrary C types. (*) GC-enabled PyObjects, anyway. Others will be naturally aligned thanks to the memory allocator. What's more, I think you shouldn't be doing this kind of change in a bugfix release. It might break compiled C extensions since you are changing some characteristics of object layout (although you would probably only break those extensions which access the GC header, which is probably not many of them). Resource consumption improvements generally go only into the next feature release. Regards Antoine.

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Re: [Python-Dev] cpython: expose TCP_FASTOPEN and MSG_FASTOPEN
by Antoine Pitrou 13 Dec '12

13 Dec '12

On Thu, 13 Dec 2012 04:24:54 +0100 (CET) benjamin.peterson <python-checkins(a)python.org> wrote: > http://hg.python.org/cpython/rev/5435a9278028 > changeset: 80834:5435a9278028 > user: Benjamin Peterson <benjamin(a)python.org> > date: Wed Dec 12 22:24:47 2012 -0500 > summary: > expose TCP_FASTOPEN and MSG_FASTOPEN > > files: > Misc/NEWS | 3 +++ > Modules/socketmodule.c | 7 ++++++- > 2 files changed, 9 insertions(+), 1 deletions(-) > > > diff --git a/Misc/NEWS b/Misc/NEWS > --- a/Misc/NEWS > +++ b/Misc/NEWS > @@ -163,6 +163,9 @@ > Library > ------- > > +- Expose the TCP_FASTOPEN and MSG_FASTOPEN flags in socket when they're > + available. This should be documented, no? Regards Antoine.

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Emacs users: hg-tools-grep
by Barry Warsaw 12 Dec '12

12 Dec '12

Hark fellow Emacsers. All you unenlightened heathens can stop reading now. A few years ago, my colleague Jono Lange wrote probably the best little chunk of Emacs lisp ever. `M-x bzr-tools-grep` lets you easily search a Bazaar repository for a case-sensitive string, providing you with a nice *grep* buffer which you can scroll through. When you find a code sample you want to look at, C-c C-c visits the file and plops you right at the matching line. You *only* grep through files under version control, so you get to ignore generated files, and compilation artifacts, etc. Of course, this doesn't help you for working on the Python code base, because Mercurial. I finally whipped up this straight up rip of Jono's code to work with hg. I'm actually embarrassed to put a copyright on this thing, and would happily just donate it to Jono, drop it in Python's Misc directory, or slip it like a lump of coal into the xmas stocking of whoever wants to "maintain" it for the next 20 years. But anyway, it's already proven enormously helpful to me, so here it is. Cheers, -Barry P.S. Who wants to abuse Jono and Matthew's copyright again and provide a <shudder> git version? ;; Copyright (c) 2012 Barry A. Warsaw ;; ;; Permission is hereby granted, free of charge, to any person obtaining ;; a copy of this software and associated documentation files (the ;; "Software"), to deal in the Software without restriction, including ;; without limitation the rights to use, copy, modify, merge, publish, ;; distribute, sublicense, and/or sell copies of the Software, and to ;; permit persons to whom the Software is furnished to do so, subject to ;; the following conditions: ;; ;; The above copyright notice and this permission notice shall be ;; included in all copies or substantial portions of the Software. ;; ;; THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, ;; EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF ;; MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND ;; NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE ;; LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION ;; OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION ;; WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. ;; This code is based on bzr-tools.el ;; Copyright (c) 2008-2009 Jonathan Lange, Matthew Lefkowitz (provide 'hg-tools) (defconst hg-tools-grep-command "hg locate --print0 | xargs -0 grep -In %s" "The command used for grepping files using hg. See `hg-tools-grep'.") ;; Run 'code' at the root of the branch which dirname is in. (defmacro hg-tools-at-branch-root (dirname &rest code) `(let ((default-directory (locate-dominating-file (expand-file-name ,dirname) ".hg"))) ,@code)) (defun hg-tools-grep (expression dirname) "Search a branch for `expression'. If there's a C-u prefix, prompt for `dirname'." (interactive (let* ((string (read-string "Search for: ")) (dir (if (null current-prefix-arg) default-directory (read-directory-name (format "Search for %s in: " string))))) (list string dir))) (hg-tools-at-branch-root dirname (grep-find (format hg-tools-grep-command (shell-quote-argument expression)))))

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Guido, Dropbox, and Python
by Terry Reedy 12 Dec '12

12 Dec '12

For those who have not heard, Guido left Google Friday and starts at Dropbox in January. (I hope you enjoy the break in between ;-). https://twitter.com/gvanrossum/status/277126763295944705 https://tech.dropbox.com/2012/12/welcome-guido/ My question, Guido, is how this will affect Python development, and in particular, your work on async. If not proprietary info, does or will Dropbox use Python3? -- Terry Jan Reedy

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Do more at compile time; less at runtime
by Mark Shannon 11 Dec '12

11 Dec '12

Hi all, The current CPython bytecode interpreter is rather more complex than it needs to be. A number of bytecodes could be eliminated and a few more simplified by moving the work involved in handling compound statements (loops, try-blocks, etc) from the interpreter to the compiler. This simplest example of this is the while loop... while cond: body This currently compiled as start: if not cond goto end body goto start end: but it could be compiled as goto test: start: body if cond goto start which eliminates one instruction per iteration. A more complex example is a return in a try-finally block. try: part1 if cond: return X part2 finally: part3 Currently, handling the return is complex and involves "pseudo exceptions", but if part3 were duplicated by the compiler, then the RETURN bytecode could just perform a simple return. The code above would be compiled thus... PUSH_BLOCK try part1 if not X goto endif push X POP_BLOCK part3 <<< duplicated RETURN_VALUE endif: part2 POP_BLOCK part3 <<< duplicated The changes I am proposing are: Allow negative line deltas in the lnotab array (bytecode deltas would remain non-negative) Remove the SETUP_LOOP, BREAK and CONTINUE bytecodes Simplify the RETURN bytecode Eliminate "pseudo exceptions" from the interpreter Simplify (or perhaps eliminate) SETUP_TRY, END_FINALLY, END_WITH. Reverse the sense of the FOR_ITER bytecode (ie. jump on not-exhausted) The net effect of these changes would be: Reduced code size and reduced code complexity. A small (1-5%)? increase in speed, due the simplification of the bytecodes and a very small change in the number of bytecodes executed. A small change in the static size of the bytecodes (-2% to +2%)? Although this is a quite intrusive change, I think it is worthwhile as it simplifies ceval.c considerably. The interpreter has become rather convoluted and any simplification has to be a good thing. I've already implemented negative line deltas and the transformed while loop: https://bitbucket.org/markshannon/cpython-lnotab-signed I'm currently working on the block unwinding. So, Good idea? Bad idea? Should I write a PEP or is the bug tracker sufficient? Cheers, Mark.

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回复： where is the python "import" implemented
by Isml 11 Dec '12

11 Dec '12

1 0