Mailman 3 November 2021 - Python-Dev

Having Sorted Containers in stdlib?
by Bob Fang 13 Nov '21

13 Nov '21

Hi All, This is a modest proposal to consider having sorted containers (http://www.grantjenks.com/docs/sortedcontainers/ <http://www.grantjenks.com/docs/sortedcontainers/>) in standard library. I know that usually adding stuff to standard library requires some strong arguments, so I will try my best to give my reasons here: 1) Some mainstream language support them out of box: C++ for example have set/map which are sorted by the key order, and Java has TreeMap which is internally a Red-black tree. I understand languages might target different audiences, but I think Python’s standard library is quite extensive compared to peers. Consider we even have a sqlite driver in the stdlib, I do not think it is outrageous to have sorted containers. 2) These containers are not really easy to implement correctly, and usually is out of the scope of day-to-day projects. Especially considering we have a large audience of non-hardcore programmers in Python community. They may have the need to use these structures, but they do not necessarily have the skill/knowledge to implement it. 3) Granted, people can just pip install this library, but that is one extra step and less fraction is better for user experience. 4) These structures are very useful in competitive programming, I know at least in Leetcode this library is installed for Python. 5) The said library is of high implementation quality. I might be stupid here as I am not the maintainer of this library and I might be not even in a position to submit it to Python as part of stdlib, but here are some of my personal thoughts and would love to hear your opinion! Thanks! Bob

22 46

Update colorsys with YUV conversions?
by Terry Reedy 13 Nov '21

13 Nov '21

https://github.com/python/cpython/pull/29512 adds what appears to be well written conversions between RGB and YUV color systems, with tests. Are we allowing such improvements? If not, a module docstring note or comment should be added. -- Terry Jan Reedy

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Summary of Python tracker Issues
by Python tracker 12 Nov '21

12 Nov '21

ACTIVITY SUMMARY (2021-11-05 - 2021-11-12) Python tracker at https://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 7282 (+23) closed 50241 (+38) total 57523 (+61) Open issues with patches: 2886 Issues opened (46) ================== #44439: stdlib wrongly uses len() for bytes-like object https://bugs.python.org/issue44439 reopened by malin #45354: test_winconsoleio fails on Windows 11 https://bugs.python.org/issue45354 reopened by vstinner #45708: PEP 515-style formatting with underscores does not seem to wor https://bugs.python.org/issue45708 reopened by serhiy.storchaka #45732: Update python.org Windows and macOS installers to use Tk 8.6.1 https://bugs.python.org/issue45732 opened by ned.deily #45733: importlib.abc.Traversable.name does not match https://bugs.python.org/issue45733 opened by jmg #45735: Promise the long-time truth that `args=list` works https://bugs.python.org/issue45735 opened by tim.peters #45736: 2to3 does not support integer division fixing https://bugs.python.org/issue45736 opened by February291948 #45737: assertLogs to optionally not disable existing handlers https://bugs.python.org/issue45737 opened by dandiez #45738: 3.11 exec raises SystemError instead of SyntaxError on char af https://bugs.python.org/issue45738 opened by pewscorner #45739: The Python implementation of Decimal does not support the "N" https://bugs.python.org/issue45739 opened by serhiy.storchaka #45742: python -h can't find -R option https://bugs.python.org/issue45742 opened by 180909 #45743: Cleanup and simplify setup.py https://bugs.python.org/issue45743 opened by christian.heimes #45744: Fix Flawfinder C Errors https://bugs.python.org/issue45744 opened by osdotsystem #45752: copy module doc wrongly says it doesn't copy arrays https://bugs.python.org/issue45752 opened by Stefan Pochmann #45753: Further speed up Python-to-Python calls. https://bugs.python.org/issue45753 opened by Mark.Shannon #45755: Mock spec with a specialized generic class does not mock class https://bugs.python.org/issue45755 opened by kjamieson #45756: mock raises exception when using a spec with an attribute that https://bugs.python.org/issue45756 opened by kjamieson #45757: compiler emits EXTENDED_ARG + NOP sequence in 3.10 https://bugs.python.org/issue45757 opened by rok.mandeljc #45758: Crash on Py_DecRef'ing builtin object from previous run https://bugs.python.org/issue45758 opened by Victor Milovanov #45759: Improve error messages for non-matching `elif`/`else` statemen https://bugs.python.org/issue45759 opened by February291948 #45760: Remove "PyNumber_InMatrixMultiply" https://bugs.python.org/issue45760 opened by brandtbucher #45761: recursive ProcessPoolExecutor invoke unable to return result https://bugs.python.org/issue45761 opened by evan0greenup #45762: Missing `list` symbols in the object inventory https://bugs.python.org/issue45762 opened by Akarys #45764: Parse error improvement forgetting ( after def https://bugs.python.org/issue45764 opened by Carl.Friedrich.Bolz #45765: importlib.metadata fails to find distributions in empty path https://bugs.python.org/issue45765 opened by jaraco #45766: Add direct proportion option to statistics.linear_regression() https://bugs.python.org/issue45766 opened by rhettinger #45767: Fix types for dev_t processing in posix module https://bugs.python.org/issue45767 opened by AMDmi3 #45771: urllib.request.urlopen can leak socket.timeout to callers https://bugs.python.org/issue45771 opened by thorpe-dev #45772: socket.socket should be a class instead of a function https://bugs.python.org/issue45772 opened by arhadthedev #45773: Compiler hangs during jump elimination https://bugs.python.org/issue45773 opened by brandtbucher #45774: Detect SQLite in configure.ac https://bugs.python.org/issue45774 opened by erlendaasland #45775: Implementation of colorsys.rgb_to_yuv and vice versa https://bugs.python.org/issue45775 opened by thomas.stolarski #45776: abc submodule not an attribute of collections on Python 3.10.0 https://bugs.python.org/issue45776 opened by stcanny #45779: multiprocessing initializer error with CPython 3.9.6 on Apple https://bugs.python.org/issue45779 opened by zhangzheng #45780: dict. keys view behaviour diverges from set() https://bugs.python.org/issue45780 opened by gregory.p.smith #45781: Deleting __debug__ should be an SyntaxError https://bugs.python.org/issue45781 opened by Carl.Friedrich.Bolz #45783: test_freeze fails if a file is removed https://bugs.python.org/issue45783 opened by petr.viktorin #45786: Avoid allocating when exiting frame; it may be unsafe. https://bugs.python.org/issue45786 opened by Mark.Shannon #45787: HOWTO for socket programming and select documentation contradi https://bugs.python.org/issue45787 opened by AlexWaygood #45788: sys.prefix include directory on Windows https://bugs.python.org/issue45788 opened by CatherineH #45789: Python execution broken after update via Windows Store https://bugs.python.org/issue45789 opened by firewave #45790: Inaccurate phrasing in extending/newtypes_tutorial https://bugs.python.org/issue45790 opened by rtobar2 #45791: __instancecheck__ being checked on type(cls) instead of cls https://bugs.python.org/issue45791 opened by rhettinger #45792: contextvars.Token has wrong module name in Sphinx's objects.in https://bugs.python.org/issue45792 opened by hynek #45794: Email policy option for disabling RFC2231 Mime parameter foldi https://bugs.python.org/issue45794 opened by Ezekeel #45795: urllib http client vulnerable to DOS attack https://bugs.python.org/issue45795 opened by haqsek2 Most recent 15 issues with no replies (15) ========================================== #45795: urllib http client vulnerable to DOS attack https://bugs.python.org/issue45795 #45794: Email policy option for disabling RFC2231 Mime parameter foldi https://bugs.python.org/issue45794 #45790: Inaccurate phrasing in extending/newtypes_tutorial https://bugs.python.org/issue45790 #45788: sys.prefix include directory on Windows https://bugs.python.org/issue45788 #45787: HOWTO for socket programming and select documentation contradi https://bugs.python.org/issue45787 #45781: Deleting __debug__ should be an SyntaxError https://bugs.python.org/issue45781 #45775: Implementation of colorsys.rgb_to_yuv and vice versa https://bugs.python.org/issue45775 #45772: socket.socket should be a class instead of a function https://bugs.python.org/issue45772 #45771: urllib.request.urlopen can leak socket.timeout to callers https://bugs.python.org/issue45771 #45762: Missing `list` symbols in the object inventory https://bugs.python.org/issue45762 #45761: recursive ProcessPoolExecutor invoke unable to return result https://bugs.python.org/issue45761 #45756: mock raises exception when using a spec with an attribute that https://bugs.python.org/issue45756 #45755: Mock spec with a specialized generic class does not mock class https://bugs.python.org/issue45755 #45753: Further speed up Python-to-Python calls. https://bugs.python.org/issue45753 #45752: copy module doc wrongly says it doesn't copy arrays https://bugs.python.org/issue45752 Most recent 15 issues waiting for review (15) ============================================= #45792: contextvars.Token has wrong module name in Sphinx's objects.in https://bugs.python.org/issue45792 #45791: __instancecheck__ being checked on type(cls) instead of cls https://bugs.python.org/issue45791 #45790: Inaccurate phrasing in extending/newtypes_tutorial https://bugs.python.org/issue45790 #45783: test_freeze fails if a file is removed https://bugs.python.org/issue45783 #45775: Implementation of colorsys.rgb_to_yuv and vice versa https://bugs.python.org/issue45775 #45774: Detect SQLite in configure.ac https://bugs.python.org/issue45774 #45773: Compiler hangs during jump elimination https://bugs.python.org/issue45773 #45771: urllib.request.urlopen can leak socket.timeout to callers https://bugs.python.org/issue45771 #45767: Fix types for dev_t processing in posix module https://bugs.python.org/issue45767 #45766: Add direct proportion option to statistics.linear_regression() https://bugs.python.org/issue45766 #45765: importlib.metadata fails to find distributions in empty path https://bugs.python.org/issue45765 #45764: Parse error improvement forgetting ( after def https://bugs.python.org/issue45764 #45759: Improve error messages for non-matching `elif`/`else` statemen https://bugs.python.org/issue45759 #45757: compiler emits EXTENDED_ARG + NOP sequence in 3.10 https://bugs.python.org/issue45757 #45753: Further speed up Python-to-Python calls. https://bugs.python.org/issue45753 Top 10 most discussed issues (10) ================================= #45757: compiler emits EXTENDED_ARG + NOP sequence in 3.10 https://bugs.python.org/issue45757 13 msgs #28533: Remove asyncore, asynchat and smtpd modules https://bugs.python.org/issue28533 11 msgs #45723: Improve and simplify configure.ac checks https://bugs.python.org/issue45723 10 msgs #45789: Python execution broken after update via Windows Store https://bugs.python.org/issue45789 10 msgs #45235: argparse does not preserve namespace with subparser defaults https://bugs.python.org/issue45235 9 msgs #45743: Cleanup and simplify setup.py https://bugs.python.org/issue45743 9 msgs #43656: TracebackException or StackSummary.extract with capture_locals https://bugs.python.org/issue43656 8 msgs #45354: test_winconsoleio fails on Windows 11 https://bugs.python.org/issue45354 6 msgs #45776: abc submodule not an attribute of collections on Python 3.10.0 https://bugs.python.org/issue45776 6 msgs #45791: __instancecheck__ being checked on type(cls) instead of cls https://bugs.python.org/issue45791 6 msgs Issues closed (35) ================== #15967: Slaves don't seem to clean up their /tmp mess if a step fails. https://bugs.python.org/issue15967 closed by iritkatriel #21501: docs: mmap example for use in documentation https://bugs.python.org/issue21501 closed by gvanrossum #35828: test_multiprocessing_fork: segmentation error in PyDict_GetIte https://bugs.python.org/issue35828 closed by iritkatriel #38006: Crash in remove() weak reference callback of weakref.WeakValue https://bugs.python.org/issue38006 closed by nascheme #40139: mimetypes module racy https://bugs.python.org/issue40139 closed by terry.reedy #44813: generate specialization stat names list into opcode.h https://bugs.python.org/issue44813 closed by iritkatriel #45091: inspect.Parameter.__str__ does not include subscripted types i https://bugs.python.org/issue45091 closed by andrei.avk #45392: docstring of "type" could use an update https://bugs.python.org/issue45392 closed by lukasz.langa #45637: The fallback to find the current frame in the gdb helpers fail https://bugs.python.org/issue45637 closed by pablogsal #45644: Make json.tool soak up input before opening output for writing https://bugs.python.org/issue45644 closed by lukasz.langa #45689: Add the ability to give custom names to threads created by Thr https://bugs.python.org/issue45689 closed by RahulARanger #45699: AttributeError: 'list' object has no attribute 'find' https://bugs.python.org/issue45699 closed by eric.araujo #45701: Add tuple tests to `functools.lru_cache` https://bugs.python.org/issue45701 closed by rhettinger #45710: Junction/symbolic folder access error on Windows 11 https://bugs.python.org/issue45710 closed by eryksun #45712: Typo in "control flow" documentation https://bugs.python.org/issue45712 closed by zach.ware #45720: Remove shlwapi dependency on Windows https://bugs.python.org/issue45720 closed by steve.dower #45724: Segmentation fault https://bugs.python.org/issue45724 closed by iritkatriel #45730: ERROR: PyYAML-6.0-cp39-cp39-manylinux_2_5_x86_64.manylinux1_x8 https://bugs.python.org/issue45730 closed by christian.heimes #45731: Handle --enable-loadable-sqlite-extensions in configure https://bugs.python.org/issue45731 closed by christian.heimes #45734: Spam https://bugs.python.org/issue45734 closed by zach.ware #45740: StrEnum entry doesn't mention its introduction in 3.11 https://bugs.python.org/issue45740 closed by ethan.furman #45741: entry points singular? https://bugs.python.org/issue45741 closed by eric.smith #45745: ./python -m test --help output for refleaks seems wrong https://bugs.python.org/issue45745 closed by vstinner #45746: ftplib please revisit retrlines('RETR as it produces files wi https://bugs.python.org/issue45746 closed by mckenzm #45747: Detect dbm and gdbm dependencies in configure.ac https://bugs.python.org/issue45747 closed by christian.heimes #45748: "import ctypes" segfaults on Python 3.6 and Ubuntu 21.10 https://bugs.python.org/issue45748 closed by erlendaasland #45749: Silently fails to build hashlib if openssl has disabled algori https://bugs.python.org/issue45749 closed by christian.heimes #45754: [sqlite3] SQLITE_LIMIT_LENGTH is incorrectly used to check sta https://bugs.python.org/issue45754 closed by erlendaasland #45763: Detect compression libraries in configure https://bugs.python.org/issue45763 closed by christian.heimes #45777: Issue in reading files with a path longer than 256 letters aft https://bugs.python.org/issue45777 closed by steve.dower #45778: libpython.so 3.9.8 drops symbol used by third party extension https://bugs.python.org/issue45778 closed by lukasz.langa #45782: Bug in struct.pack https://bugs.python.org/issue45782 closed by steven.daprano #45784: spam https://bugs.python.org/issue45784 closed by steven.daprano #45785: Remove asyncore, asynchat and smtpd modules https://bugs.python.org/issue45785 closed by vstinner #45793: execute shell command ./configure with python subprocess.popen https://bugs.python.org/issue45793 closed by ronaldoussoren

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Adding pep-8-casing-compliant aliases for unittest and logging
by Ethan Furman 12 Nov '21

12 Nov '21

On 11/11/21 11:53 AM, Matt del Valle wrote: > Okay, so from the replies so far it looks like this is very quickly going into the 'never gonna happen' > dumpster, so in the interests of salvaging *something* out of it: [...] > I just dislike having to settle for 'it's what we've got'. With these two modules in particular, a lot > of the arguments that have been made so far either don't apply or are not as strong (such as the > confusion of having builtins.list, builtins.List and typing.List). Additionally, these are significantly > more ancillary portions of the stdlib than the builtins, much less likely to cause as severe of a > disruption (I personally don't believe a backward-compatible change like this which only adds aliases > would be as disruptive as many people claim, but concede that that's subjective), and much less likely > to have the implementation change so drastically as to want to change out types for factory functions > or vice-versa. > > So perhaps we could narrow the scope of this down to just adding snake_case aliases to the logging and > unittest modules [...] +1 I would happily change all my unittest and logging usage to snake case if those aliases existed. -- ~Ethan~

1 1

containment and the empty container
by Ethan Furman 12 Nov '21

12 Nov '21

When is an empty container contained by a non-empty container? For example: {} in {1:'a', 'b':2] <-- TypeError because of hashability set() in {1, 2, 'a', 'b'} <-- ditto [] in ['a', 'b', 1, 2] <-- False '' in 'a1b2' <-- True SomeFlag.nothing in SomeFlag.something <-- ??? Personally, I have never had a use for '' in 'some string' being True, and always have to guard against that scenario. Likewise, if an empty collection of flags is contained by a collection of flags, then that will trip me up as well; on the other hand, it seems that collections of related flags are often treated as in set theory, where the empty set is a member of any non-empty set... So, does Flag adhere to set theory, or is just happenstance that some operators work the same for both groups? Can we have `SomeFlag.nothing in SomeFlag.something` be `False`, or would that be too surprising? -- ~Ethan~

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Typing :: Typed Classifier
by rakshith.bhyravabhotla＠gmail.com 09 Nov '21

09 Nov '21

Hi, What are the implications of using a Typing :: typed classifier? Is it simply "the package has typing"? Or does it have a more extensive implication?

2 1

NASA Inquiry
by Elmore, Charita R. (GSFC-705.0)[TELOPHASE CORP] 09 Nov '21

09 Nov '21

REF: RITM1146898 Hello, my name is Charita Elmore and I am a Supply Chain Risk Management Coordinator at NASA.  As such, I ensure that all NASA acquisitions of Covered Articles comply with Section 208 of the Further Consolidated Appropriations Act, 2020, Public Law 116-94, enacted December 20, 2019.  To do so, the Country of Origin (CoO) information must be obtained from the developer of the product(s).  Specifically, identify the country where the original code was developed: * Homebrew package: mpdecimal [cid:image001.png@01D7D539.7FD581F0]

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PEP 467: Minor bytes and bytearray improvements
by Ethan Furman 09 Nov '21

09 Nov '21

The final PEP with SC feedback incorporated and one last addition: `bytes.ascii` as a replacement for the Python 2 idiom of `str(some_var)` to get the bytes version, and the Python 3 workaround of either the correct `str(some_var).encode('astii') or the potentially wrong `ascii(some_var).encode('ascii'). The rendered version is at https://www.python.org/dev/peps/pep-0467/ Happy reading! PEP: 467 Title: Minor API improvements for binary sequences Version: $Revision$ Last-Modified: $Date$ Author: Nick Coghlan <ncoghlan(a)gmail.com>, Ethan Furman <ethan(a)stoneleaf.us> Status: Draft Type: Standards Track Content-Type: text/x-rst Created: 30-Mar-2014 Python-Version: 3.11 Post-History: 2014-03-30 2014-08-15 2014-08-16 2016-06-07 2016-09-01 2021-04-13 2021-11-03 Abstract ======== This PEP proposes five small adjustments to the APIs of the ``bytes`` and ``bytearray`` types to make it easier to operate entirely in the binary domain: * Add ``fromsize`` alternative constructor * Add ``fromint`` alternative constructor * Add ``ascii`` alternative constructor * Add ``getbyte`` byte retrieval method * Add ``iterbytes`` alternative iterator Rationale ========= During the initial development of the Python 3 language specification, the core ``bytes`` type for arbitrary binary data started as the mutable type that is now referred to as ``bytearray``. Other aspects of operating in the binary domain in Python have also evolved over the course of the Python 3 series, for example with PEP 461. Motivation ========== With Python 3 and the split between ``str`` and ``bytes``, one small but important area of programming became slightly more difficult, and much more painful -- wire format protocols. This area of programming is characterized by a mixture of binary data and ASCII compatible segments of text (aka ASCII-encoded text). The addition of the new constructors, methods, and iterators will aid both in writing new wire format code, and in porting any remaining Python 2 wire format code. Common use-cases include ``dbf`` and ``pdf`` file formats, ``email`` formats, and ``FTP`` and ``HTTP`` communications, among many others. Proposals ========= Addition of explicit "count and byte initialised sequence" constructors ----------------------------------------------------------------------- To replace the now discouraged behavior, this PEP proposes the addition of an explicit ``fromsize`` alternative constructor as a class method on both ``bytes`` and ``bytearray`` whose first argument is the count, and whose second argument is the fill byte to use (defaults to ``\x00``):: >>> bytes.fromsize(3) b'\x00\x00\x00' >>> bytearray.fromsize(3) bytearray(b'\x00\x00\x00') >>> bytes.fromsize(5, b'\x0a') b'\x0a\x0a\x0a\x0a\x0a' >>> bytearray.fromsize(5, fill=b'\x0a') bytearray(b'\x0a\x0a\x0a\x0a\x0a') ``fromsize`` will behave just as the current constructors behave when passed a single integer, while allowing for non-zero fill values when needed. Addition of explicit "single byte" constructors ----------------------------------------------- As binary counterparts to the text ``chr`` function, this PEP proposes the addition of an explicit ``fromint`` alternative constructor as a class method on both ``bytes`` and ``bytearray``:: >>> bytes.fromint(65) b'A' >>> bytearray.fromint(65) bytearray(b'A') These methods will only accept integers in the range 0 to 255 (inclusive):: >>> bytes.fromint(512) Traceback (most recent call last): File "<stdin>", line 1, in <module> ValueError: integer must be in range(0, 256) >>> bytes.fromint(1.0) Traceback (most recent call last): File "<stdin>", line 1, in <module> TypeError: 'float' object cannot be interpreted as an integer The documentation of the ``ord`` builtin will be updated to explicitly note that ``bytes.fromint`` is the primary inverse operation for binary data, while ``chr`` is the inverse operation for text data, and that ``bytearray.fromint`` also exists. Behaviorally, ``bytes.fromint(x)`` will be equivalent to the current ``bytes([x])`` (and similarly for ``bytearray``). The new spelling is expected to be easier to discover and easier to read (especially when used in conjunction with indexing operations on binary sequence types). As a separate method, the new spelling will also work better with higher order functions like ``map``. These new methods intentionally do NOT offer the same level of general integer support as the existing ``int.to_bytes`` conversion method, which allows arbitrarily large integers to be converted to arbitrarily long bytes objects. The restriction to only accept positive integers that fit in a single byte means that no byte order information is needed, and there is no need to handle negative numbers. The documentation of the new methods will refer readers to ``int.to_bytes`` for use cases where handling of arbitrary integers is needed. Addition of "ascii" constructors -------------------------------- In Python 2 converting an object, such as the integer ``123``, to bytes (aka the Python 2 ``str``) was as simple as:: >>> str(123) '123' With Python 3 that became the more verbose:: >>> b'%d' % 123 or even:: >>> str(123).encode('ascii') This PEP proposes that an ``ascii`` method be added to ``bytes`` and ``bytearray`` to handle this use-case:: >>> bytes.ascii(123) b'123' Note that ``bytes.ascii()`` would handle simple ascii-encodable text correctly, unlike the `ascii()`` built-in:: >>> ascii("hello").encode('ascii') b"'hello'" Addition of "getbyte" method to retrieve a single byte ------------------------------------------------------ This PEP proposes that ``bytes`` and ``bytearray`` gain the method ``getbyte`` which will always return ``bytes``:: >>> b'abc'.getbyte(0) b'a' If an index is asked for that doesn't exist, ``IndexError`` is raised:: >>> b'abc'.getbyte(9) Traceback (most recent call last): File "<stdin>", line 1, in <module> IndexError: index out of range Addition of optimised iterator methods that produce ``bytes`` objects --------------------------------------------------------------------- This PEP proposes that ``bytes`` and ``bytearray`` gain an optimised ``iterbytes`` method that produces length 1 ``bytes`` objects rather than integers:: for x in data.iterbytes(): # x is a length 1 ``bytes`` object, rather than an integer For example:: >>> tuple(b"ABC".iterbytes()) (b'A', b'B', b'C') Design discussion ================= Why not rely on sequence repetition to create zero-initialised sequences? ------------------------------------------------------------------------- Zero-initialised sequences can be created via sequence repetition:: >>> b'\x00' * 3 b'\x00\x00\x00' >>> bytearray(b'\x00') * 3 bytearray(b'\x00\x00\x00') However, this was also the case when the ``bytearray`` type was originally designed, and the decision was made to add explicit support for it in the type constructor. The immutable ``bytes`` type then inherited that feature when it was introduced in PEP 3137. This PEP isn't revisiting that original design decision, just changing the spelling as users sometimes find the current behavior of the binary sequence constructors surprising. In particular, there's a reasonable case to be made that ``bytes(x)`` (where ``x`` is an integer) should behave like the ``bytes.fromint(x)`` proposal in this PEP. Providing both behaviors as separate class methods avoids that ambiguity. Omitting the originally proposed builtin function ------------------------------------------------- When submitted to the Steering Council, this PEP proposed the introduction of a ``bchr`` builtin (with the same behaviour as ``bytes.fromint``), recreating the ``ord``/``chr``/``unichr`` trio from Python 2 under a different naming scheme (``ord``/``bchr``/``chr``). The SC indicated they didn't think this functionality was needed often enough to justify offering two ways of doing the same thing, especially when one of those ways was a new builtin function. That part of the proposal was therefore dropped as being redundant with the ``bytes.fromint`` alternate constructor. Developers that use this method frequently will instead have the option to define their own ``bchr = bytes.fromint`` aliases. Scope limitation: memoryview ---------------------------- Updating ``memoryview`` with the new item retrieval methods is outside the scope of this PEP. References ========== .. [1] Initial March 2014 discussion thread on python-ideas (https://mail.python.org/pipermail/python-ideas/2014-March/027295.html) .. [2] Guido's initial feedback in that thread (https://mail.python.org/pipermail/python-ideas/2014-March/027376.html) .. [3] Issue proposing moving zero-initialised sequences to a dedicated API (http://bugs.python.org/issue20895) .. [4] Issue proposing to use calloc() for zero-initialised binary sequences (http://bugs.python.org/issue21644) .. [5] August 2014 discussion thread on python-dev (https://mail.python.org/pipermail/python-ideas/2014-March/027295.html) .. [6] June 2016 discussion thread on python-dev (https://mail.python.org/pipermail/python-dev/2016-June/144875.html) Copyright ========= This document has been placed in the public domain.

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Re: containment and the empty container
by John Melendowski 09 Nov '21

09 Nov '21

I think he's confusing the fact that empty is a subset of every set

1 0

Oh wow, this is really impressive
by Steven D'Aprano 08 Nov '21

08 Nov '21

I was using Python 3.10 and got this NameError when I mistyped a name: NameError: name 'KeyboardInterrupted' is not defined. Did you mean: 'KeyboardInterrupt'? It even works for attribute errors too. That's fantastic! This is a really amazing useability improvement, thank you everyone who was involved! I literally squeed :-) I just may spend a few days deliberately mistyping names in the REPL just to see this :-) -- Steve

4 3