Mailman 3 June 2011 - Python-Dev

Re: [Python-Dev] [Python-checkins] peps: Add rules for indenting continuation lines.
by Barry Warsaw 03 Jun '11

03 Jun '11

On Jun 02, 2011, at 08:09 PM, guido.van.rossum wrote: >+ Continuation lines should align wrapped elements either vertically using >+ Python's implicit line joining inside parentheses, brackets and braces, >+ or using a hanging indent of double your code indention, in which case >+ there should be no argument on the first line. For example: >+ >+ Yes: # Aligned with opening delimiter >+ foo = long_function_name(var_one, var_two, >+ var_three, var_four) >+ >+ # Double code indention for hanging indent; nothing on first line >+ foo = long_function_name( >+ var_one, var_two, var_three, >+ var_four) >+ >+ No: # Stuff on first line forbidden >+ foo = long_function_name(var_one, var_two, >+ var_three, var_four) >+ >+ # 2-space hanging indent forbidden >+ foo = long_function_name( >+ var_one, var_two, var_three, >+ var_four) As I mentioned to Guido, I'm not sure where the double-indent recommendation comes from, but it's entirely possible I missed that discussion. I agree with the recommendations, but think a single-indentation level looks fine. E.g. return dict( fqdn_listname=member.mailing_list, address=member.address.email, role=role, user=path_to('users/{0}'.format(member.user.user_id)), self_link=path_to('members/{0}'.format(member.member_id)), ) or return b'{0}://{1}:{2}/{3}/{4}'.format( ('https' if as_boolean(config.webservice.use_https) else 'http'), config.webservice.hostname, config.webservice.port, config.webservice.api_version, (resource[1:] if resource.startswith('/') else resource), ) -Barry

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Windows download links not working for 2.7.2rc1 and 3.1.4rc1
by Michael Foord 02 Jun '11

02 Jun '11

Hey all, The links to the Windows downloads for 2.7.2rc1 and 3.1.4rc1 are 404. (From the release pages.) http://python.org/ftp/python/3.1.3/python-3.1.4rc1.msi http://python.org/ftp/python/2.7.1/python-2.7.2rc1.msi All the best, Michael Foord -- http://www.voidspace.org.uk/ May you do good and not evil May you find forgiveness for yourself and forgive others May you share freely, never taking more than you give. -- the sqlite blessing http://www.sqlite.org/different.html

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Re: [Python-Dev] [Python-checkins] cpython: The compiler class for EMX was removed
by Nick Coghlan 02 Jun '11

02 Jun '11

On Thu, Jun 2, 2011 at 3:47 AM, eric.araujo <python-checkins(a)python.org> wrote: > http://hg.python.org/cpython/rev/c3f8991cd74d > changeset: 70587:c3f8991cd74d > user: Éric Araujo <merwok(a)netwok.org> > date: Wed Jun 01 15:20:44 2011 +0200 > summary: > The compiler class for EMX was removed This is the kind of checkin comment where the phrasing is a little confusing. It could mean either "was removed by mistake and has now been restored" or else "is no longer supported and has been removed". (Checking the diff resolves the ambiguity in favour of the latter interpretation, but not all diffs are as simple as this one). It's worth trying to make the final state of the source tree explicit in the checkin message (no need to edit the history, just a note for future reference). Cheers, Nick. -- Nick Coghlan | ncoghlan(a)gmail.com | Brisbane, Australia

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Re: [Python-Dev] [Python-checkins] cpython (2.7): Multiple clean-ups to the docs for builtin functions.
by Terry Reedy 02 Jun '11

02 Jun '11

On 6/1/2011 6:50 PM, raymond.hettinger wrote: > - with open("mydata.txt") as fp: > - for line in iter(fp.readline, "STOP"): > process_line(line) As noted on the tracker, this will always loop forever. Even if "STOP" is corrected to "STOP\n", it will still loop forever if the file does not have the magic value. > + with open('mydata.txt') as fp: > + for line in iter(fp.readline, ''): > process_line(line) While I have a big problem with infinite loops, I have a (smaller) problem with useless code. The new loop line line is a roundabout way to spell "for line in fp". While this would have been useful before files were turned into iterables (if there was such a time after iter() was introduced), it is not now. What might be useful and what the example could show is how to stop early if a sentinel is present, while still stopping when the iterable runs out. The following alternate fix to the original does just that. with open("mydata.txt") as fp: for line in iter(fp.__next__, "STOP\n"): process_line(line) A tested a runnable variation with and without the exact sentinal. It generalizes to *any* iteration than one might want to stop early. This still has the objection that the loop could be written as for line in fp: if line == "STOP\n": break process_line(line) which is easily generalized to any stopping conditions. It is hard to think of useful examples of iter(func, sentinal). To be sure of someday stopping, func must someday (either certainly or with probability 1) either raise StopIteration or produce the sentinal (which should therefore be hard to misspell). To be useful, func should not be a method of an iterable (or at least not produce the same objects as the iterable would when iterated.) It also must produce different values, at least sometimes, when called, which means either maintaining internal state or pulling values from another source. Here is a completely different example which meets these criteria. It can actually be run (though not doctested ;-). It uses random.randint to produce 25 random waiting times for a binary process to hit one of the two values. from random import randint for i in range(25): print(sum(iter(lambda:randint(0,1), 0)), end=',') The outer loop could be removed, but it hints at how this could be used for empirical probability studies. --- Terry Jan Reedy

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Question about Module Loading
by Timothy Kadich 01 Jun '11

01 Jun '11

If a Python program imported a module, say numpy for example, where in the source is this line interpreted and then handled by import.c ? Thank you in advance!

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Docs for the packaging module
by Éric Araujo 01 Jun '11

01 Jun '11

Hi, The docs were not added alongside the code when packaging was merged back into CPython because they were not in a shape conforming with the rest of the docs. I’d like your input on layout so that I can fix this ASAP and merge the docs. (They would still require a lot of additions, fixes and improvements after that, but at least they’d be in the repo.) The easiest part is the library documentation, i.e. the docs for developers of packaging-related tools that want to use for example packaging.version or packaging.metadata to do their own stuff. These documents should go into Doc/library/packaging.*, I think this is a no-brainer. (Distutils has only a stub here, its API docs is mixed with its usage docs.) There is a guide for end-users, which contains an outdated copy of the old “Installing Python Modules” and a few documents about the new pysetup script (superseder of setup.py scripts), which are not integrated with the first document. I think those should supersede the existing distutils-based Doc/install tree. We want to advertise pysetup and packaging as the way of gettting modules in 3.3. A question remains: is it worthwhile to keep the old document somewhere? Last but not least, the doc for authors wanting to package and distribute their project (“Distributing Python Modules”, Doc/distutils). I think we should not overwrite this directory, because the directory name is tied to distutils and because there will be users needing that documentation (distutils is not removed). So, is it okay to create a new Doc/packaging directory and change the link on the docs front page from distutils to packaging? (Technical question: I think I’ll get a complaint from Sphinx that distutils is not included in any toctree; I’ll try adding a toctree from library/distutils to distutils/index and see if that works.) Thanks for reading

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Re: [Python-Dev] [Python-checkins] cpython: test.support: add requires_mac_ver() function
by Ezio Melotti 01 Jun '11

01 Jun '11

Hi, On 01/06/2011 13.28, victor.stinner wrote: > http://hg.python.org/cpython/rev/35212b113730 > changeset: 70574:35212b113730 > user: Victor Stinner<victor.stinner(a)haypocalc.com> > date: Wed Jun 01 12:28:04 2011 +0200 > summary: > test.support: add requires_mac_ver() function I would expect this to be a decorator, similar to requires_IEEE_754 and requires_zlib. > Add also linux_version() to __all__. For consistency, this should be a decorator too, possibly named requires_linux_ver(). A requires_windows(_ver) sounds like a useful addition too, given the number of tests that are specific to Windows. > files: > Lib/test/support.py | 22 +++++++++++++++++++++- > Lib/test/test_math.py | 7 ++++--- > 2 files changed, 25 insertions(+), 4 deletions(-) > > > diff --git a/Lib/test/support.py b/Lib/test/support.py > --- a/Lib/test/support.py > +++ b/Lib/test/support.py > @@ -37,7 +37,8 @@ > "Error", "TestFailed", "ResourceDenied", "import_module", > "verbose", "use_resources", "max_memuse", "record_original_stdout", > "get_original_stdout", "unload", "unlink", "rmtree", "forget", > - "is_resource_enabled", "requires", "find_unused_port", "bind_port", > + "is_resource_enabled", "requires", "linux_version", "requires_mac_ver", > + "find_unused_port", "bind_port", > "IPV6_ENABLED", "is_jython", "TESTFN", "HOST", "SAVEDCWD", "temp_cwd", > "findfile", "sortdict", "check_syntax_error", "open_urlresource", > "check_warnings", "CleanImport", "EnvironmentVarGuard", "TransientResource", > @@ -299,6 +300,25 @@ > except ValueError: > return 0, 0, 0 > > +def requires_mac_ver(*min_version): > + """Raise SkipTest if the OS is Mac OS X and the OS X version if less than > + min_version. > + > + For example, support.requires_linux_version(10, 5) raises SkipTest if the This should be requires_mac_ver > + version is less than 10.5. > + """ > + if sys.platform != 'darwin': > + return > + version_txt = platform.mac_ver()[0] > + try: > + version = tuple(map(int, version_txt.split('.'))) > + except ValueError: > + return > + if version< min_version: > + min_version_txt = '.'.join(map(str, min_version)) > + raise unittest.SkipTest("Mac OS X %s or higher required, not %s" > + % (min_version_txt, version_txt)) > + > HOST = 'localhost' > > def find_unused_port(family=socket.AF_INET, socktype=socket.SOCK_STREAM): > diff --git a/Lib/test/test_math.py b/Lib/test/test_math.py > --- a/Lib/test/test_math.py > +++ b/Lib/test/test_math.py > @@ -2,6 +2,7 @@ > # XXXX Should not do tests around zero only > > from test.support import run_unittest, verbose, requires_IEEE_754 > +from test import support > import unittest > import math > import os > @@ -669,10 +670,10 @@ > self.assertTrue(math.isnan(math.log2(NAN))) > > @requires_IEEE_754 > - @unittest.skipIf(sys.platform == 'darwin' > - and platform.mac_ver()[0].startswith('10.4.'), > - 'Mac OS X Tiger log2() is not accurate enough') > def testLog2Exact(self): > + # log2() is not accurate enough on Mac OS X Tiger (10.4) > + support.requires_mac_ver(10, 5) > + > # Check that we get exact equality for log2 of powers of 2. > actual = [math.log2(math.ldexp(1.0, n)) for n in range(-1074, 1024)] > expected = [float(n) for n in range(-1074, 1024)] > Best Regards, Ezio Melotti

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