Mailman 3 April 2013 - Python-Dev

Re: [Python-Dev] Difference in RE between 3.2 and 3.3 (or Aaron Swartz memorial)
by Matěj Cepl May 5, 2013

May 5, 2013

On 2013-02-26, 16:25 GMT, Terry Reedy wrote: > On 2/21/2013 4:22 PM, Matej Cepl wrote: >> as my method to commemorate Aaron Swartz, I have decided to port his >> html2text to work fully with the latest python 3.3. After some time >> dealing with various bugs, I have now in my repo >> https://github.com/mcepl/html2text (branch python3) working solution >> which works all the way to python 3.2 (inclusive; >> https://travis-ci.org/mcepl/html2text). However, the last problem >> remains. This >> >> <li>Run this command: >> <pre>ls -l *.html</pre></li> >> <li>?</li> >> >> should lead to >> >> * Run this command: >> >> ls -l *.html >> >> * ? >> >> but it doesn’t. It leads to this (with python 3.3 only) >> >> * Run this command: >> ls -l *.html >> >> * ? >> >> Does anybody know about something which changed in modules re or >> http://docs.python.org/3.3/whatsnew/changelog.html between 3.2 and >> 3.3, which could influence this script? > > Search the changelob or 3.3 misc/News for items affecting those two > modules. There are at least 4. > http://docs.python.org/3.3/whatsnew/changelog.html > > It is faintly possible that the switch from narrow/wide builds to > unified builds somehow affected that. Have you tested with 2.7/3.2 on > both narrow and wide unicode builds? So, in the end, I have went the long way and bisected cpython to find the commit which broke my tests, and it seems that the culprit is http://hg.python.org/cpython/rev/123f2dc08b3e so it is clearly something Unicode related. Unfortunately, it really doesn't tell me what exactly is broken (is it a known regression) and if there is known workaround. Could anybody suggest a way how to find bugs on http://bugs.python.org related to some particular commit (plain search for 123f2dc0 didn’t find anything). Any thoughts? Matěj P.S.: Crossposting to python-devel in hope there would be somebody understanding more about that particular commit. For that I have also intentionally not trim the original messages to preserve context. -- http://www.ceplovi.cz/matej/, Jabber: mcepl<at>ceplovi.cz GPG Finger: 89EF 4BC6 288A BF43 1BAB 25C3 E09F EF25 D964 84AC When you're happy that cut and paste actually works I think it's a sign you've been using X-Windows for too long. -- from /. discussion on poor integration between KDE and GNOME

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enum discussion: can someone please summarize open issues?
by Georg Brandl May 4, 2013

May 4, 2013

Hi all, I've just read a few dozen enum-related emails, and there are so many more. I would like to form an opinion about the proposal(s), but I feel I don't know what the actual issues are anymore. In the past, somebody usually presented a summary of the issues so far, and that was a good point for late comers to get up to speed and weigh in. (It can be here or in the PEP.) It is also a good point to focus the discussion (which seems to have wandered quite far from sensible Pythonic design in places). Thanks in advance, Georg

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PEP-435 reference implementation
by Ethan Furman May 2, 2013

May 2, 2013

Greetings, Eli asked me to put the reference implementation here for review. It is available at https://bitbucket.org/stoneleaf/aenum in ref435.py and test_ref435.py -- ~Ethan~

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Re: [Python-Dev] enum discussion: can someone please summarize open issues?
by Ethan Furman May 2, 2013

May 2, 2013

[re-directing back to python-dev] On 04/28/2013 08:42 PM, Davis Silverman wrote: > as a not super experienced python developer, when i see Season('AUTUMN') it looks like im creating an a Season object. I > understand your resoning, that it acts like a boolean singleton, however, i feel it would confuse many, and isn't worth > it. From what i see, its meant to be a lookup sort of thing, but it doesnt really feel like one. > > Or am i completely wrong about something? As far as you are concerned, you are creating a Season object. That it happens to be a pre-existing Season object is an implementation detail, and the whole thing would work just as well if it did indeed create a brand new object (you couldn't use `is` then, but in general `is` shouldn't be used anyway and I see no reason why `is` should be encouraged with Enums; use `==`). Two examples: - the first few integers (up to 256 now, I think) are pre-created by the interpreter; when you do `int('7')` you are not getting a brand-new, never before used, integer 7 object, you're getting a cached integer 7 object. - all booleans (yup, both of them ;) are pre-created; when you ask for a True or a False, you are not getting a brand new one. Since `is` is discouraged, both of those cases could go the other way (always creating a brand new object) and properly written programs would continue to run just fine -- slower, but fine. Enums are the same: they could return brand new instances every time, and programs using `==` to compare will keep on working. That they don't is an implementation detail. The real guarantee with enums is that once you have one created you'll only ever see the original values; so class Last(Enum): X = 1 Y = 2 Z = 3 will only have three possible elements, X, Y, and Z, and X will always have the value of 1, Y will always have the vale of 2, and Z will always have the value of 3. If you try and get `Last("W")` you'll trigger an exception, just like you do with `int("house")`. -- ~Ethan~

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noob contributions to unit tests
by Sean Felipe Wolfe May 1, 2013

May 1, 2013

Hey everybody how are you all :) I am an intermediate-level python coder looking to get help out. I've been reading over the dev guide about helping increase test coverage --> http://docs.python.org/devguide/coverage.html And also the third-party code coverage referenced in the devguide page: http://coverage.livinglogic.de/ I'm seeing that according to the coverage tool, two of my favorite libraries, urllib/urllib2, have no unit tests? Is that correct or am I reading it wrong? If that's correct it seems like a great place perhaps for me to cut my teeth and I would be excited to learn and help out here. And of course any thoughts or advice for an aspiring Python contributor would be appreciated. Of course the dev guide gives me plenty of good info. Thanks! -- A musician must make music, an artist must paint, a poet must write, if he is to be ultimately at peace with himself. - Abraham Maslow

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Enumeration items: `type(EnumClass.item) is EnumClass` ?
by Ethan Furman May 1, 2013

May 1, 2013

[creating new thread] On 04/29/2013 01:30 AM, Steven D'Aprano wrote: > On Sun, Apr 28, 2013 at 11:50:16PM -0700, Ethan Furman wrote: > >> In other words, currently: >> >> class Color(Enum): >> red = 1 >> green = 2 >> blue = 3 >> >> class MoreColor(Color): >> cyan = 4 >> magenta = 5 >> yellow = 6 >> black = 7 >> >> MoreColor.red is Color.red # True > > Correct. > > >> But as soon as: >> >> type(Color.red) is Color # True >> type(MoreColor.red) is MoreColor # True > > I don't believe this is correct. As I understand it, the proposal is the > weaker guarantee: > > isinstance(Color.red, Color) # True, possibly using __instancecheck__ Words from Guido: On 04/23/2013 08:11 AM, Guido van Rossum wrote: > I gotta say, I'm with Antoine here. It's pretty natural (also coming > from other languages) to assume that the class used to define the > enums is also the type of the enum values. Certainly this is how it > works in Java and C++, and I would say it's the same in Pascal and > probably most other languages. > On 04/25/2013 02:54 PM, Guido van Rossum wrote: > I don't know what's going on, but it feels like we had this same > discussion a week ago, and I still disagree. Disregarding, the C[i] > notation, I feel quite strongly that in the following example: > > class Color(Enum): > red = 1 > white = 2 > blue = 3 > orange = 4 > > the values Color.red etc. should be instances of Color. This is how > things work in all other languages that I am aware of that let you > define enums. On 04/25/2013 03:19 PM, Guido van Rossum wrote: > I suppose you were going to propose to use isinstance() overloading, > but I honestly think that Color.red.__class__ should be the same > object as Color. On 04/25/2013 03:37 PM, Guido van Rossum wrote: > TBH I had a hard time getting over the fact that even though the class > said "a = 1", C.a is not the integer 1. But I did get over it. > Hopefully you can get over *this* weirdness. [and from the summary thread] On 04/28/2013 01:02 PM, Guido van Rossum wrote: > On Sun, Apr 28, 2013 at 12:32 PM, Ethan Furman wrote: >> >> - should enum items be of the type of the Enum class? (i.e. type(SPRING) >> is Seasons) > > IMO Yes.

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enum instances
by Marco Hemmelrath April 30, 2013

April 30, 2013

First of all, hi, I'm new to this list. Following the enum discussions on this list I am kind of confused about how enums and their respective instances, i.e. the values, should behave in "normal" context. I apologize beforehand for the mass of "questions" because the following contains really many discussed things but they all kinda depend on one another, and for terminology which I might've missed. Considering we have[1]: class Color(enum): red = 1 white = 2 other = "undefined" class State(enum): idle = 0 busy = 1 idling = idle ideling = 0 together with the premises: 1. type(State.busy) == State 2. type(State) == enum 3. isinstance(State.idle, State) 4. State.idle is State.idle which should mostly be agreed on (if I didn't misinterpret). How would an enum instance (e.g. State.busy) behave in normal Python expressions? Should these instances just wrap their values and provide some simple overhead useful for enums? I'll just note down a few examples of how I think it could work and express a few thoughts on them: 1. State.busy == 1 2. State.busy == Color.red 3. int(State.Busy) is 1 4. isinstance(State.busy, int) 5. Color.other.startswith("und") 6. State.busy is not 1 7. State.busy is not Color.red 8. State.idle in State 9. 0 in State # True, False or raise? 10. State.idling is State.idle 11. State.idle == State.idling 12. State.idle is not State.idling 1. & 2. Considering that enum components contain a value this value should be accessable and comperable. If it wasn't then there would be no real need to assign a value to it because everything must be compared using the is operator anyway. In this case an entirely new syntax could be implemented but since I think this is not what we want I'll skip this. Futhermore, if enum instances should compare equal to their values but unequal to each other this creates weird circumstances like: Color.red == 1 == State.busy -but- Color.red != State.busy == 1 3. Similar to 1. an enum instance's value /should/ be accessable as an expression by itself when needed besides simple operations like compatisons. This might be really tricky because the object in question is still of type State and some existing uses might break even though I can't think of any. What would certainly be a problem in this case though is that repr() would not reveal the value but the actual enum instance. This could be problematic when the enum instance's value is not a standard type or when repr() and str() differ and repr() is what's needed. 4. Combines 1. and 2. in class relation. It could be argued that the actual value should be an instance of its type subclassed by the enum class (State) which is in turn a subclass of enum. Going further on this it could also allow various things like class EnumWithInt(enum, int) which would only allow integers as its enum identifiers. This goes slightly into the IntEnum direction but with more flexibility. 5. Related to 3. in that this also allows attribute access to the enum instance's value. Considering that the enum instance should already be an instance of its value type as well this kinda speaks for itself. 6. & 7. Obviously, these can't be true even though they compare equal (see 1. and 2.). 8. Check if an enum instance is a member of State. Since in this case the same can also be achieved by using isinstance or by comparing the instance's type, this is mostly interesting for subclassing enums because, but I won't that cover here because it would probably be too much. 9. Analog to 8. this could either return just work, simply return False because this object is obviously not a member of State or raise an exception because of a type mismatch (not an enum instance). Also interesting for subclassing enums. 10. See premise 4. on this. 11. & 12. Even though these compare equal and even if their value object is actually the same they themseves should /not/ be the same object. Someone needs to find a use case for this though because as of now I can only think of this being Pythonic. So, the most critical part of this would probably be 3. to 7. regarding the value types. I'd love to read some thoughts and comments on that. Regards, Marco [1]: http://mail.python.org/pipermail/python-dev/2013-April/125738.html

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Destructors and Closing of File Objects
by Nikolaus Rath April 30, 2013

April 30, 2013

[ Note: I already asked this on http://stackoverflow.com/questions/15917502 but didn't get any satisfactory answers] Hello, The description of tempfile.NamedTemporaryFile() says: ,---- | If delete is true (the default), the file is deleted as soon as it is | closed. `---- In some circumstances, this means that the file is not deleted after the program ends. For example, when running the following test under py.test, the temporary file remains: ,---- | from __future__ import division, print_function, absolute_import | import tempfile | import unittest2 as unittest | class cache_tests(unittest.TestCase): | def setUp(self): | self.dbfile = tempfile.NamedTemporaryFile() | def test_get(self): | self.assertEqual('foo', 'foo') `---- In some way this makes sense, because this program never explicitly closes the file object. The only other way for the object to get closed would presumably be in the __del__ destructor, but here the language references states that "It is not guaranteed that __del__() methods are called for objects that still exist when the interpreter exits." So everything is consistent with the documentation so far. However, I'm confused about the implications of this. If it is not guaranteed that file objects are closed on interpreter exit, can it possibly happen that some data that was successfully written to a (buffered) file object is lost even though the program exits gracefully, because it was still in the file objects buffer and the file object never got closed? Somehow that seems very unlikely and un-pythonic to me, and the open() documentation doesn't contain any such warnings either. So I (tentatively) conclude that file objects are, after all, guaranteed to be closed. But how does this magic happen, and why can't NamedTemporaryFile() use the same magic to ensure that the file is deleted? Best, -Nikolaus -- »Time flies like an arrow, fruit flies like a Banana.« PGP fingerprint: 5B93 61F8 4EA2 E279 ABF6 02CF A9AD B7F8 AE4E 425C

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Enumeration items: mixed types?
by Ethan Furman April 30, 2013

April 30, 2013

This just doesn't make sense to me: --> class Stuff(Enum): ... blue = 1 ... china = 'really big country' ... random = (8273.199, 517) --> Stuff.blue.name == 'blue' --> Stuff.blue.value == 1 --> Stuff.china.name == 'china' --> Stuff.china.value == ??? --> Stuff.random.name == 'random' --> Stuff.china.value == ??? In order to make this work at all, we have to support auto-numbering, and I didn't think we were going to do that in the class syntax? -- ~Ethan~ P.S. Apologies for all the questions, I'm just hoping to get the last details hammered out so we can stop discussing Enums. ;)

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Biggest Fake Conference in Computer Science
by eliswilson＠hushmail.com April 30, 2013

April 30, 2013

Biggest Fake Conference in Computer Science We are researchers from different parts of the world and conducted a study on the world’s biggest bogus computer science conference WORLDCOMP http://sites.google.com/site/worlddump1 organized by Prof. Hamid Arabnia from University of Georgia, USA. We submitted a fake paper to WORLDCOMP 2011 and again (the same paper with a modified title) to WORLDCOMP 2012. This paper had numerous fundamental mistakes. Sample statements from that paper include: (1). Binary logic is fuzzy logic and vice versa (2). Pascal developed fuzzy logic (3). Object oriented languages do not exhibit any polymorphism or inheritance (4). TCP and IP are synonyms and are part of OSI model (5). Distributed systems deal with only one computer (6). Laptop is an example for a super computer (7). Operating system is an example for computer hardware Also, our paper did not express any conceptual meaning. However, it was accepted both the times without any modifications (and without any reviews) and we were invited to submit the final paper and a payment of $500+ fee to present the paper. We decided to use the fee for better purposes than making Prof. Hamid Arabnia richer. After that, we received few reminders from WORLDCOMP to pay the fee but we never responded. This fake paper is different from the two fake papers already published (see https://sites.google.com/site/worlddump4 for details) in WORLDCOMP. We MUST say that you should look at the above website if you have any thoughts of participating in WORLDCOMP. DBLP and other indexing agencies have stopped indexing WORLDCOMP’s proceedings since 2011 due to its fakeness. See http://www.informatik.uni-trier.de/~ley/db/conf/icai/index.html for of one of the conferences of WORLDCOMP and notice that there is no listing after 2010. See Section 2 of http://sites.google.com/site/dumpconf for comments from well-known researchers about WORLDCOMP. The status of your WORLDCOMP papers can be changed from scientific to other (i.e., junk or non-technical) at any time. Better not to have a paper than having it in WORLDCOMP and spoil the resume and peace of mind forever! Our study revealed that WORLDCOMP is money making business, using University of Georgia mask, for Prof. Hamid Arabnia. He is throwing out a small chunk of that money (around 20 dollars per paper published in WORLDCOMP’s proceedings) to his puppet (Mr. Ashu Solo or A.M.G. Solo) who publicizes WORLDCOMP and also defends it at various forums, using fake/anonymous names. The puppet uses fake names and defames other conferences to divert traffic to WORLDCOMP. He also makes anonymous phone calls and threatens the critiques of WORLDCOMP (See Item 7 of Section 5 of above website). That is, the puppet does all his best to get a maximum number of papers published at WORLDCOMP to get more money into his (and Prof. Hamid Arabnia’s) pockets. Prof. Hamid Arabnia makes a lot of tricks. For example, he appeared in a newspaper to fool the public, claiming him a victim of cyber-attack (see Item 8 in Section 5 of above website). Monte Carlo Resort (the venue of WORLDCOMP for more than 10 years, until 2012) has refused to provide the venue for WORLDCOMP’13 because of the fears of their image being tarnished due to WORLDCOMP’s fraudulent activities. That is why WORLDCOMP’13 is taking place at a different resort. WORLDCOMP will not be held after 2013. The draft paper submission deadline is over but still there are no committee members, no reviewers, and there is no conference Chairman. The only contact details available on WORLDCOMP’s website is just an email address! We ask Prof. Hamid Arabnia to publish all reviews for all the papers (after blocking identifiable details) since 2000 conference. Reveal the names and affiliations of all the reviewers (for each year) and how many papers each reviewer had reviewed on average. We also ask him to look at the Open Challenge (Section 6) at https://sites.google.com/site/moneycomp1 and respond if he has any professional values. Sorry for posting to multiple lists. Spreading the word is the only way to stop this bogus conference. Please forward this message to other mailing lists and people. We are shocked with Prof. Hamid Arabnia and his puppet’s activities at http://worldcomp-fake-bogus.blogspot.com Search Google using the keyword worldcomp fake for additional links.

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