[issue7430] cmp still sends messages
Mark Dickinson dicki...@gmail.com added the comment: Fixed in r76663, r76664. Thanks for the report! -- resolution: - fixed status: open - closed versions: +Python 3.2 ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue7430 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue7406] int arithmetic relies on C signed overflow behaviour
Mark Dickinson dicki...@gmail.com added the comment: Zooko: Yes; that's the sort of solution that's needed if we're not allowed to assume two's complement with the extraordinary value (- sys.maxint - 1) not a trap representation. If we are allowed to assume this, then more efficient solutions are available. Also, if we're not allowed to assume two's complement + no trap representation, then int_and, int_xor, int_or are plain wrong: For ones' complement or sign-and-magnitude, the result of these logical operations won't match the result of the corresponding operations on longs, for negative operands. For two's complement with (-sys.maxint-1) a trap representation, int_and and int_xor should be producing a Python long instead of a Python int in some cases: -sys.maxint ^ 1 should be -sys.maxint - 1, which wouldn't be representable as a Python int. That's why I want to make these extra assumptions beyond what's guaranteed by the C standards; working around them introduces inefficiencies for all implementations, for the benefit of implementations that (probably) don't even exist. -- ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue7406 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue7048] decimal.py: logb: round the result if it is greater than prec
Mark Dickinson dicki...@gmail.com added the comment: Mike Cowlishaw has confirmed that the tests scbx164, scbx165 (in version 2.59 of the tests) are implementation-specific, so test_decimal is doing the right thing in skipping them. So I think this issue can be closed. I don't think it's worth removing the restriction on the 2nd scaleb argument: while I still think it's arbitrary and unnecessary, keeping it allows us to say that we're in full compliance with the specification. -- resolution: - fixed status: open - closed ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue7048 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue1923] meaningful whitespace can be lost in rfc822_escape
Changes by Antoine Pitrou pit...@free.fr: -- assignee: - tarek nosy: +tarek ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue1923 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue7433] MemoryView memory_getbuf causes segfaults, double call to tp_releasebuffer
Antoine Pitrou pit...@free.fr added the comment: Why do you say that: There is no feasible way the bf_releasebuffer can keep track of how many calls to it have been made. Because that's exactly what e.g. bytearray objects do (see the ob_exports field in Objects/bytearrayobject.c). -- nosy: +pitrou ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue7433 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue7385] MemoryView_FromObject crashes if PyBuffer_GetBuffer fails
Antoine Pitrou pit...@free.fr added the comment: Nice catch. I wonder whether there's a simple way of cooking up an unit test for this (short of creating a new extension type). -- assignee: - pitrou nosy: +pitrou priority: - high stage: - needs patch versions: +Python 2.7, Python 3.2 ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue7385 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue7433] MemoryView memory_getbuf causes segfaults, double call to tp_releasebuffer
Pauli Virtanen p...@iki.fi added the comment: Why do you say that: There is no feasible way the bf_releasebuffer can keep track of how many calls to it have been made. I was probably thinking about allocating new temporary arrays for strides etc. on each *_getbuffer -- if that's done, then manually keeping track of all the allocated memory seems like a waste of effort (ie. not feasible). But yes, if memory allocated for entries in Py_buffer is shared between all exported buffer views, that sounds better -- for some reason I didn't think about that... So we'll do it like this in Numpy then. But still, I take it that the way it currently works is not the intended behavior? The segmentation faults caused by this came as a bit of a surprise to me, as the assumption about paired *_getbuffer and *_releasebuffer calls is very natural. -- ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue7433 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue7433] MemoryView memory_getbuf causes segfaults, double call to tp_releasebuffer
Antoine Pitrou pit...@free.fr added the comment: I was probably thinking about allocating new temporary arrays for strides etc. on each *_getbuffer -- if that's done, then manually keeping track of all the allocated memory seems like a waste of effort (ie. not feasible). Yes, I know it looks very painful to do so. I am not responsible for the Py_buffer / memorview design, however. Travis Oliphant is, and I hear he's a member of the Numpy community: you might want to ask him for advice. (the general problem is that managing Py_buffers can entail memory allocations, but Py_buffer is not a PyObject and therefore you can't take advantage of Python's general object management facilities) But still, I take it that the way it currently works is not the intended behavior? The segmentation faults caused by this came as a bit of a surprise to me, as the assumption about paired *_getbuffer and *_releasebuffer calls is very natural. Well, those calls still /are/ paired, aren't they? There is one odd thing which you must be careful about, it is that *_getbuffer can be called with a NULL Py_buffer pointer. -- ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue7433 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue7433] MemoryView memory_getbuf causes segfaults, double call to tp_releasebuffer
Pauli Virtanen p...@iki.fi added the comment: I think this is an implementation issue in MemoryView rather than an issue with the buffer interface. PEP 3118 states, This same bufferinfo structure must be passed to bf_releasebuffer (if available) when the consumer is done with the memory. -- this is not guaranteed by the current MemoryView implementation. The calls are not paired: the *_getbuf calls fill in structures with data view1, and view2. The *_releasebuf calls receive structures with data view1, and view1. The data filled in the second getbuf call (view2) is never passed back to *_releasebuf, as it is overwritten with view1 data by dup_buffer. To work around this, *_releasebuf must be written so that it does not use the view pointer passed to it -- the data structure may have been shallow copied and any memory pointers in it may have already been freed. I can try to cook up a patch fixing this. -- ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue7433 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue7327] format: minimum width: UTF-8 separators and decimal points
Eric Smith e...@trueblade.com added the comment: See the discussion on python-dev, in particular Martin's comment at http://mail.python.org/pipermail/python-dev/2009-December/094412.html The solutions to this seem too complex for 2.x. It is not a problem in 3.x. -- resolution: - wont fix status: open - closed ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue7327 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue7433] MemoryView memory_getbuf causes segfaults, double call to tp_releasebuffer
Antoine Pitrou pit...@free.fr added the comment: To work around this, *_releasebuf must be written so that it does not use the view pointer passed to it -- the data structure may have been shallow copied and any memory pointers in it may have already been freed. I can try to cook up a patch fixing this. If you can do it without breaking the current unit tests (Lib/test/test_memoryview.py) this would be nice indeed. -- ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue7433 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue7434] pprint doesn't know how to print a namedtuple
New submission from Anthony Foglia afog...@gmail.com: It would be nice if pprint could format namedtuples wrapping lines as it does with tuples. Looking at the code, this does not look like an easy task. Completely rewriting pprint to allow it to be extensible to user-created classes would be best, but involve a ton of work. Simple making all named tuples derive from a named tuple base class (itself derived from tuple) would be simpler, albeit more of a hack. -- components: Library (Lib) messages: 95968 nosy: afoglia severity: normal status: open title: pprint doesn't know how to print a namedtuple type: feature request versions: Python 2.6 ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue7434 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue7434] pprint doesn't know how to print a namedtuple
Changes by Benjamin Peterson benja...@python.org: -- assignee: - rhettinger nosy: +rhettinger ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue7434 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue7427] BadStatusLine is hell to debug
Jake McGuire j...@youtube.com added the comment: I think what's happening is that your connection is being closed due to inactivity, so the status line that comes back is empty. Printing repr(line) would probably make the emptiness clear, but maybe the httplib code should put in a more specific message in this case... -- nosy: +jakemcguire ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue7427 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue7426] StringIO and with statement
Brian Curtin cur...@acm.org added the comment: #1286 looks related -- nosy: +brian.curtin ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue7426 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue7426] StringIO and with statement
Changes by Alexandre Vassalotti alexan...@peadrop.com: -- resolution: - duplicate stage: - committed/rejected status: open - closed superseder: - fileinput, StringIO, and cStringIO do not support the with protocol ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue7426 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue7435] Int/Long: some tests are duplicate and error messages refer to long
New submission from flox la...@yahoo.fr: In python 3.x there's a single type for integer: int. The automatic conversion of the test suite has created many tests which are duplicate of each other. The attached patch removes duplication of tests, and fix the strings for these modules: Lib/random.py Lib/test/mapping_tests.py Lib/test/pickletester.py Lib/test/string_tests.py Lib/test/test_binop.py Lib/test/test_builtin.py Lib/test/test_datetime.py Lib/test/test_decimal.py Lib/test/test_descr.py Lib/test/test_dict.py Lib/test/test_getargs2.py Lib/test/test_int.py Lib/test/test_long.py Lib/test/test_types.py -- components: Tests messages: 95971 nosy: flox severity: normal status: open title: Int/Long: some tests are duplicate and error messages refer to long versions: Python 3.2 ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue7435 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue7435] Int/Long: some tests are duplicate and error messages refer to long
Changes by flox la...@yahoo.fr: -- keywords: +patch Added file: http://bugs.python.org/file15449/issue7435_py3k.diff ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue7435 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue7436] Define 'object with assignable attributes'
New submission from Terry J. Reedy tjre...@udel.edu: On Python list, someone asked what guarantees that functions have and will continue to have assignable attributes. I started to say 'the docs' but failed to find anything specific in 7.6. Function definitions or LibRef 5.12.3. Functions (all references to 3.1/2a docs). 5.3.1 Attribute references says The primary must evaluate to an object of a type that supports attribute references, which most objects do. That is true for reading/getting but not for writing/setting. 6.2. Assignment statements says If the target is an attribute reference: The primary expression in the reference is evaluated. It should yield an object with assignable attributes; But which are those? I propose to add a sentence like Objects with assignable attributes include modules, user-defined (Python-coded) functions and classes, and instances of such classes. If this leaves anything out, it can be expanded. I tested and was somewhat surprised to modules based on C code (_socket, _tkinter) allowed attribute setting. I use 'user'defined' because the docs do in several places. I added 'Python-coded' because that is the real relevant characteristic. C-coded user-defined functions in user-written extension modules do not have settable attributes (I presume), whereas imported Python-coded functions, in stdlib or 3-rd party modules do. LibRef 5.12.3 There are really two flavors of function objects: built-in functions and user-defined functions. could leave a reader wondering about imported functions. A sentence could also be added there User-defined (Python-coded) functions have assignable attributes. -- assignee: georg.brandl components: Documentation messages: 95972 nosy: georg.brandl, tjreedy severity: normal status: open title: Define 'object with assignable attributes' ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue7436 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue1771] Remove cmp parameter to list.sort() and builtin.sorted()
Tom Switzer thomas.swit...@gmail.com added the comment: I am not sure I understand the reasoning behind removing the cmp parameter (and agree with Lea Wiemann). Trying to wedge a proper comparison into the key parameter is clumsy and unreadable (as can be seen in the 2to3 example above). The intrinsic ordering on objects does not necessarily match up with the way you want to sort them. For example, a natural intrinsic order on 2 points in 2d is lexicographical, however you often want to sort by angular order relative to some other point instead. Clearly this can never be put in __cmp__ or __lt__, because the sorted order is relative to some other unknown point. Trying to do this with the key function doesn't make sense; it would not be clear you are sorting by angular order and you'd have to instantiate a bunch of wrapper objects just to do basic sorting. Another quick example would be sorting hyperplanes by intersection on a ray. Sorting points along a direction given by a vector. I understand removing redundant features from a language, but I just can't see how key replaces this functionality in a readable or efficient way. This highlights an important class of cases (since it was mentioned that none could be thought of) in which we wish to make comparisons between values where a comparison (, or ==) is more numerically sound, more efficient, or the only option (perhaps the ordering is defined explicitly) then computing the exact values (eg. angle). As far as it seems, the only way to do this with key is by following the example given and creating a class solely to wrap each object that overrides __cmp__, which is certainly non-obvious (ie. there is no one, obvious way to do it). -- nosy: +tixxit ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue1771 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue7406] int arithmetic relies on C signed overflow behaviour
Terry J. Reedy tjre...@udel.edu added the comment: I consider the binary bitwise operations, for negative ints, to be either undefined or wrongly implemented. Consider the following (3.1) 3^2 1 -3^2 -1 3^-2 -3 -3^-2 3 2^3 1 -2^3 -3 Something change sign just flips the sign of the result, sometimes it also changes the magnitude. From the viewpoint of arithmetic, and signed base-two representations, the latter seems senseless. The doc says only The ^ operator yields the bitwise XOR (exclusive OR) of its arguments, which must be integers. But it does not define what bitwise XOR means for signed ints, as opposed to unsigned bit strings, possible interpreted as (unsigned) counts, which is the traditional domain of bit-operation definition. So there is no way to predict the result for negative ints. Or rather, the sensible prediction does not match the observed behavior. My impression is that Python longs are signed magnitudes. If so, the bitwise ops should arguably be the signed result of the op on the magnitudes. -- nosy: +tjreedy ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue7406 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue1771] Remove cmp parameter to list.sort() and builtin.sorted()
Guido van Rossum gu...@python.org added the comment: Can someone provide a code sample to make this argument more understandable for those of us who don't compare points by angular order for a living... :-) I'm not sure what the 2to3 example (I presume you mean msg59937) shows except that conversion from a cmp function to a key function may require you to actually think... Also, for all of you asking for cmp back, I hope you realize that sorting N values using a custom cmp function makes about N log N calls calls to cmp, whereas using a custom key calls the key function only N times. This means that even if your cmp function is faster than the best key function you can write, the advantage is lost as N increases (which is just where you'd like it to matter most :-). -- ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue1771 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue7406] int arithmetic relies on C signed overflow behaviour
Tim Peters tim.pet...@gmail.com added the comment: Terry, the language reference also says: For the purpose of shift and mask operations, a binary representation is assumed, and negative numbers are represented in a variant of 2's complement which gives the illusion of an infinite string of sign bits extending to the left. That explains every result you saw: 3 = ...11 2 = ...10 1 = ...01 -3 = ...01 2 = ...10 -1 = ...11 3 = ...11 -2 = ...10 -3 = ...01 -3 = ...01 -2 = ...10 3 = ...11 2 = ...10 3 = ...11 1 = ...01 -2 = ...10 3 = ...11 -3 = ...01 In every case, the result is simply the xor of the inputs viewed as infinite bitstrings. And it works exactly the same way if you use |, , , , or unary ~. It's true that CPython's longs are /implemented/ via sign-magnitude, but that should never be visible in the result of any operation. -- nosy: +tim_one ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue7406 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue6594] json C serializer performance tied to structure depth on some systems
Antoine Pitrou pit...@free.fr added the comment: Here is a new patch with an internal memo dict to reuse equal keys, and some tests. -- stage: - patch review versions: +Python 3.2 Added file: http://bugs.python.org/file15450/json-opts2.patch ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue6594 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue6594] json C serializer performance tied to structure depth on some systems
Changes by Antoine Pitrou pit...@free.fr: Removed file: http://bugs.python.org/file15444/json-opts.patch ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue6594 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue7435] Int/Long: some tests are duplicate and error messages refer to long
Changes by Antoine Pitrou pit...@free.fr: -- nosy: +eric.smith, mark.dickinson ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue7435 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue7437] OS X 2.6.4 installer fails on 10.3 with two corrupted file names, ignored on 10.4
New submission from Ned Deily n...@acm.org: See the thread starting at http://mail.python.org/pipermail/pythonmac- sig/2009-December/021907.html for full details. It appears two vestigial gif files included in the 2.6.4 OS installer are being installed under corrupted file names by the OS X Installer.app under 10.3 and 10.4. While the error is silently ignored on 10.4, it apparently causes the whole install to fail on 10.3. The problem does not seem to occur when installing on 10.5 or 10.6. It is also not limited to that installer image: I was able to reproduce the problem with an installer I built on 10.5. However, an installer built on 10.4 from the same source snapshot seems to have the correct file names. Without knowing exactly why those two file names, and only those two, are corrupted, it seems risky to let this seemingly minor problem go unresolved. And it apparently prevents 2.6.4 from being installed on 10.3, a more serious problem. -- assignee: ronaldoussoren components: Macintosh messages: 95978 nosy: ned.deily, ronaldoussoren severity: normal status: open title: OS X 2.6.4 installer fails on 10.3 with two corrupted file names, ignored on 10.4 versions: Python 2.6 ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue7437 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue1923] meaningful whitespace can be lost in rfc822_escape
Tarek Ziadé ziade.ta...@gmail.com added the comment: Notice that we are also losing something else that can mean a lot in reST : empty lines. They also need to be escaped. But we can't do it properly unless we encode empty lines with something else than a 8 space line because when rfc822.Message reads it, it removes it. -- ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue1923 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue7438] Allow to use a part of subprocess module during building Python
New submission from Arfrever Frehtes Taifersar Arahesis arfrever@gmail.com: It is sometimes useful to call subprocess.Popen() in setup.py of Python. Currently it would fail, because subprocess module tries to import some modules, which not always are used. I suggest to delay some imports. -- components: Library (Lib) files: subprocess.py-2.7.patch keywords: patch messages: 95980 nosy: Arfrever severity: normal status: open title: Allow to use a part of subprocess module during building Python versions: Python 2.7, Python 3.2 Added file: http://bugs.python.org/file15451/subprocess.py-2.7.patch ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue7438 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue7438] Allow to use a part of subprocess module during building Python
Changes by Arfrever Frehtes Taifersar Arahesis arfrever@gmail.com: Added file: http://bugs.python.org/file15452/subprocess.py-3.2.patch ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue7438 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue7439] Bug or expected behavior? I cannot tell.
New submission from David W. Lambert b49p23t...@stny.rr.com: Raymond Hettinger posted clever Hamming number generator, http://code.activestate.com/recipes/576961/ which I tried to modify. The function gives incorrect output when called as hamming_numbers(shorthand = True). It seemed reasonable to expect the two arrangements of statements controlled by the shorthand boolean to be functionally equivalent. http://docs.python.org/3.1/reference/executionmodel.html is relevant, and makes me think this is not a bug, but I wish it were. I'd appreciate your determination. Thanks, Dave. from itertools import tee, chain, islice, groupby from heapq import merge def hamming_numbers(shorthand = False): def deferred_output(): for i in output: yield i result, p2, p3, p5 = tee(deferred_output(), 4) if shorthand: # Lambert modification m = [(a*x for x in p) for (a,p,) in ((2,p2),(3,p3),(5,p5))] assert m[0] is not m[2] merged = merge(*m) else: # original m2 = (2*x for x in p2) m3 = (3*x for x in p3) m5 = (5*x for x in p5) merged = merge(m2, m3, m5) combined = chain([1], merged) output = (k for k, v in groupby(combined)) return result if __name__ == '__main__': print(list(islice(hamming_numbers(), 10))) print(list(islice(hamming_numbers(True), 10))) -- components: Interpreter Core messages: 95981 nosy: LambertDW severity: normal status: open title: Bug or expected behavior? I cannot tell. type: behavior versions: Python 3.1 ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue7439 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue1771] Remove cmp parameter to list.sort() and builtin.sorted()
Raymond Hettinger rhettin...@users.sourceforge.net added the comment: FWIW, we had a long discussion on comp.lang.python and the net result was that no use cases were found that required a cmp function. One complex case (sorting recursive tree structures) at first appeared to need a cmp-function but was found to be simpler and faster using a key-function. The net result of the conversation was the feeling that people who have grown-up using cmp-functions in either Python, C or some other language feel like they've lost something but really haven't. In contrast, people who use SQL or spreadsheet database tools find that key functions come naturally since neither supports cmp-functions, instead preferring the user to specify primary and secondary key functions. Also, it was pointed-out the removal of cmp-functions in sorted() and list.sort() was part of a larger effort to remove all forms of cmp from the whole language (i.e. the builtin cmp function is gone and so it the __cmp__ magic method). Rich comparisons have completely supplanted all uses of cmp-functions in the language as a whole -- having multiple ways to do it was confusing. In converting code from 2-to-3, we have found two sticky cases. The first occurs when an API had exposed cmp functions to the end-user (for example, unittest.getTestCaseNames() and unittest.makeSuite() have an optional sortUsing parameter that allows the user to specify a cmp-function). To support that use case (so that end-user API's would not have to be changed), we added a CmpToKey() tool which automatically converts cmp-functions to key functions. This tool is referenced in the docs and it could be added to the 2-to-3 converter. The second case occurs when a primary key is sorted ascending and a secondary key is sorted descending. The technique for that is to take advantage of sort stability and do two sorts: s.sort(key=secondary, reverse=True) s.sort(key=primary) # now sorted by primary ascending, secondary descending That technique is going to be documented in an update of the sorting how-to. It doesn't seem to arise much in practice and the cmp function equivalent seems to be harder for beginners to write (though at least it can be done with a single cmp-function and a single sort). -- ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue1771 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue7434] pprint doesn't know how to print a namedtuple
Raymond Hettinger rhettin...@users.sourceforge.net added the comment:
I agree with you that pprint needs to be rewritten to make it more
extensible.
I do not see a straight-forward way of handling your feature request.
First, namedtuple() is a factory function and is not itself a class, so
there is no standard way to recognize one. Essentially, a named tuple
is concept (any class that supported both sequence behavior and
attribute access is a named tuple, for example the time structure is a
named tuple but not created by the collections.namedtuple() factory
function, instead is a C structseq which has substantially similar
characteristics). This means that pprint has no reliable way to tell if
one of its arguments is a named tuple.
Second, collections.namedtuple() is intentionally designed to let the
user override the default __repr__() method (see an example in the
namedtuple docs). That means that pprint cannot know in advance how a
named tuple is supposed to display.
At best, I can imagine that pprint() grows the ability to print a
multi-line repr (as specified by the object itself) but indented to a
level controlled by pprint(). The pprint() function would scan the repr
for newlines and replace them with a newline followed by the appropriate
number of spaces.
For example:
class Point(namedtuple('Point', 'x y z')):
... 'Point with a multi-line repr'
... def __repr__(self):
... return 'Point(\n x=%r,\n y=%r,\n z=%r\n
)' % self
Point(3,4,5)
Point(
x=3,
y=4,
z=5
)
pprint([Point(3,4,5), Point(6,7,8)])
[Point(
x=3,
y=4,
z=5
),
Point(
x=6,
y=7,
z=8
)
]
Alternatively, the pprint module could introduce a new magic method to
support multi-line reprs when the repr itself it too long fit in a
single line:
class MyList(list):
... def __multirepr__(self):
... 'Return a list of strings to pprint'
... return Multi(head = 'Mylist([',
... body = [str(x).upper() for x in self],
... tail = '])
pprint(MyList(['now', 'is', 'the', 'time', 'for']), width=15)
MyList(['NOW',
'IS',
'THE',
'TIME',
'FOR',
])
In summary, there are several ways to approach this problem but they are
centered on building-out pprint(), not on changing collections.namedtuple().
--
assignee: rhettinger -
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[issue7440] distutils shows incorrect Python version in MSI installers
New submission from Mario Vilas mvi...@gmail.com: I just hit this silly bug in distutils, should be quite easy to fix. When building MSI installers for a target_version other than the current Python version, the target directory selection dialog shows a wrong message. For example, here is a screen capture of an installer built using Python 2.6, but setting the target as Python 2.5. The message says: The destination directory should contain a Python 2.6 installation when it should be: The destination directory should contain a Python 2.5 installation. -- assignee: tarek components: Distutils files: msi_installer_wrong_message.png messages: 95984 nosy: MarioVilas, tarek severity: normal status: open title: distutils shows incorrect Python version in MSI installers type: behavior versions: Python 2.6 Added file: http://bugs.python.org/file15453/msi_installer_wrong_message.png ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue7440 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue7440] distutils shows incorrect Python version in MSI installers
Mario Vilas mvi...@gmail.com added the comment: My proposed patch is to change line 506 of bdist_msi.py from this: version = sys.version[:3]+ to this: version = self.target_version[:3]+ which is what I did to work around the problem. -- ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue7440 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
