Mailman 3 July 2020 - Python-Dev

PEP 622 idea: "match case object" to represent match patterns
by Federico Salerno 18 Jul '20

18 Jul '20

Recent discussion on the store vs. load syntax issues of PEP 622 prompted a (yet unripe) idea that could hopefully spur some progress. What if cases required some sort of MatchCase (name pending) object which could be preconstructed by the user if needed, but also inferred on the fly if absent? I think an example would clarify what I mean. Consider the following block (with & to mark "load" just for demonstration purposes): match some_point: case Point(x, y, _) if x > y: print(f"Tridimensional point with x > y") case Point(_, _, _): print("Some other 3D point.") case Point(_, &my_y) as pt: print(f"{pt} has y=={my_y}.") case Point(10, _): print("Some bidimensional point with x==10.") case Point(_, y): print(f"Bidimensional point with {y=}.") case _: print("Something else.") This is admittedly simple enough that it wouldn't require what I'm about to show, but it does require marking my_y in some way to prevent it from being interpreted as a "store" identifier, or to namespace it for the same reason. Now consider the following refactor: 3d_point = MatchCase("Point(x, y, z)") other_3d_point = MatchCase("Point(_, _, _)") point_with_my_y = MatchCase("Point(_, {})", my_y) # syntax with {} is debatable. other_2d_point = MatchCase("Point(_, y)") match some_point: case 3d_point if 3d_point[0] > 3d_point[1]: # 3d_point exposes x, y, and zwith the names given # in the declaration, as well as numerically, # through __getitem__ or perhaps also through attributes # like .args and .kwargs. ... case other_3d_point: # other_3d_point[0] through [2] are available, while # other_3d_point["_"] == other_3d_point[2] because it's the last # one that was given. Presumably the programmer wouldn't care about it. ... case point_with_my_y as pt: # pt still exposes positional arguments like pt[0], pt[1] or pt.args # as well as pt["_"] (== pt[0] in this case), but pt[1] has no # equivalent in pt.kwargs because no name was given. ... case Point(10, _): # Python would construct its own MatchCase here and behave as expected. ... case other_2d_point: print(f"Bidimensional point with y={other_2d_point['y']}.") case _: ... Every case above could be constructed in the same way as in the example without MatchCase, except for point_with_my_y, which contains a lookup: every identifier inside the match is interpreted as "store" unless it's namespaced; the others are included for demonstration purposes. As seen in case Point(10, _), patterns that contain no "load" identifiers can be written without using MatchCase instances. In effect, its usage would be a sort of "plug-in" for when complex or verbose functionality is needed, allowing to load identifiers or encode patterns for readability and/or reuse through the match block. The value of the identifiers to load would be read at MatchCase instantiation and internally converted to a constant value. Guard clauses could optionally be included in the MatchCase instantiation. If both it and the case: provide guards, they are anded together. If deemed appropriate, a special meaning could be given to MatchCase() (no arguments, or with "" or even any falsy value as argument) to represent the default case to appease those who don't like _. Note that the above examples assume at least _ (and possibly any identifier) can be repeated. My proposed MatchCase idea is compatible with the possibility of disallowing repeated identifiers, while still allowing them in MatchCase()'s first argument with the behaviour seen in the other_3d_point case. The constructor MatchCase could be either provided as a builtin or in a stdlib module that must be imported. I think the latter would be more reasonable. Any specific syntax or name presented above (MatchCase, the {}s in its first argument, the names of the MatchCase.args and MatchCase.kwargs attributes) is debatable. I hope I haven't missed any important point that would make the above demonstration invalid. Any thoughts?

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PEP 622: capturing into an explicit namespace
by Richard Levasseur 17 Jul '20

17 Jul '20

Hi Python-dev and PEP 622 Authors, I saw this idea, or something like it, posted by a couple of people, but didn't see much discussion of it, and skimming the PEP today, I didn't see a mention of it. Maybe I just missed it; my apologies if so, and a link to the relevant discussion/text would be appreciated. In any case, the basic idea was to have an explicit namespace that captures are put into, and is treated as assignment instead of lookup. e.g. match get_point() into m: case Point(m.x, m.y): print(m.x, m.y) ...etc... A variation I saw was "as" instead of "into"; the particular token is bikeshedding. The core idea is an explicit name that is "special" within the match's case expressions. Personally, I thought this was a rather elegant solution to the load-vs-store problem for names. This is because, essentially, it changes the mental model from "some non-dotted names are special, some aren't, keep a careful eye out" to "only "m." is special, everything else is regular". I haven't thought about this too deeply (analysis tools might benefit, too?); I wanted to keep this initial email short before investing time/energy/thought into it in case it had already been discussed and discarded.

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Re: PEP 622: Structural Pattern Matching (version 2)
by Mark Shannon 17 Jul '20

17 Jul '20

Hi, As I wrote in an earlier email: > > For a PEP to succeed it needs to show two things. > > 1. Exactly what problem is being solved, or need is to be fulfilled, and that is a sufficiently large problem, or need, to merit the proposed change. > > 2. That the proposed change is the best known solution for the problem being addressed. > > IMO, PEP 622 fails on both counts. > This email addresses point 1 (for version 2). Abstract -------- Why the use of "shape" in "scare quotes"? It worries me that the abstract can't explain what PEP 622 does directly. Could you use a real example in the abstract? Using a contrived example like this seems like a straw man. It feels like it is constructed to favour the PEP, whilst being unlike any real code. Rationale and Goals ------------------- > Python programs frequently need to handle data which varies in type, presence of attributes/keys, or number of elements. Typical examples are operating on nodes of a mixed structure like an AST, handling UI events of different types, processing structured input (like structured files or network messages), or “parsing” arguments for a function that can accept different combinations of types and numbers of parameters. AST, and UI objects usually (pretty much always) form a class hierarchy, making is easy to add utility matching methods to the base class. Where matching *might* have some value is when unrelated types are involved, but you need to show that enhanced destructuring would be insufficient. > In fact, the classic 'visitor' pattern is an example of this, done in an OOP style -- but matching makes it much less tedious to write. This might be true of the "classic" visitor pattern, but that's a straw man. The Python visitor pattern is a joy to use. Each case gets its own self contained method, clearly named, which is much better than a giant `match` statement. > Much of the code to do so tends to consist of complex chains of nested if/elif statements, including multiple calls to len(), isinstance() and index/key/attribute access. Inside those branches users sometimes need to destructure the data further to extract the required component values, which may be nested several objects deep. There seem to be three things you want to enhance here: Unpacking; to avoid calls to `len` Type checking; to avoid calls to `isinstance`. To avoiding nesting by using complex lvalues. You fail to justify why the first two cannot be handled separately with much simpler extensions to the language and why complex lvalues are better than nesting. The examples ------------ There are only three examples, none of which are compelling. In fact, two of them serve as a warning against the additional complexity this PEP entails. Django example: ''''''''''''''' Saves two lines of code, but introduces two bugs! (Assuming that the original behavior should be preserved) If the authors of the PEP cannot use this feature correctly in the first example they give, what chance do the rest of us have? is_tuple example: ''''''''''''''''' (Repeating my earlier email) Python's support for OOP provides an alternative to ADTs. For example, by adding a simple "matches" method to Node and Leaf, `is_tuple` can be rewritten as something like: def is_tuple(node): if not isinstance(node, Node): return False return node.matches("(", ")") or node.matches("(", ..., ")") The "switch on http response codes" example. '''''''''''''''''''''''''''''''''''''''''''' This clearly demonstrates the value of symbolic constants for readability and the serious flaw in the PEP that I cannot use them. I really don't see you how you can claim that `case 406:` is more readable than `elif response == HTTP_UPGRADE_REQUIRED:` ? Preventing the use of symbolic constants or other complex rvalues is a impairment to usability. Silently failing when symbolic constants are used is terrible. I do see the value of a `switch` statement for repeated tests against the same value; its intent is clearer than repeated `elif`s. But there is no need for it to be so hard to use. Cheers, Mark.

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Summary of Python tracker Issues
by Python tracker 17 Jul '20

17 Jul '20

ACTIVITY SUMMARY (2020-07-10 - 2020-07-17) 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 7550 (+20) closed 45517 (+35) total 53067 (+55) Open issues with patches: 3067 Issues opened (39) ================== #39960: Using typename.__setattr__ in extension type with Py_TPFLAGS_H https://bugs.python.org/issue39960 reopened by gvanrossum #41271: Add support for io_uring to cpython https://bugs.python.org/issue41271 opened by cooperlees #41272: New clause in FOR and WHILE instead of ELSE https://bugs.python.org/issue41272 opened by catrudis #41273: asyncio: proactor read transport: use recv_into instead of rec https://bugs.python.org/issue41273 opened by tontinton #41275: Clarify whether Futures can be awaited multiple times https://bugs.python.org/issue41275 opened by JustAnotherArchivist #41277: documentation: os.setxattr() errno EEXIST and ENODATA https://bugs.python.org/issue41277 opened by w0rthle$$ #41278: IDLE: Clarify some completion details in doc https://bugs.python.org/issue41278 opened by Alex-Python-Programmer #41279: Convert StreamReaderProtocol to a BufferedProtocol https://bugs.python.org/issue41279 opened by tontinton #41281: Wrong/missing code formats in datetime documentation https://bugs.python.org/issue41281 opened by yyyyyyyan #41282: Deprecate and remove distutils https://bugs.python.org/issue41282 opened by jaraco #41283: The parameter name for imghdr.what in the documentation is wro https://bugs.python.org/issue41283 opened by aeltawela #41287: __doc__ attribute is not set in property-derived classes https://bugs.python.org/issue41287 opened by Sergei Izmailov #41292: Dead link in Windows FAQ https://bugs.python.org/issue41292 opened by Michel Samia #41293: fix confusing example in hashlib docs https://bugs.python.org/issue41293 opened by Pavel Trukhanov #41294: Allow '__qualname__' to be an instance of 'DynamicClassAttribu https://bugs.python.org/issue41294 opened by WildCard65 #41295: CPython 3.8.4 regression on __setattr__ in multiinheritance wi https://bugs.python.org/issue41295 opened by kam193 #41297: Remove doctest import from heapq https://bugs.python.org/issue41297 opened by alexchandel #41298: Enable handling logoff and shutdown Windows console events https://bugs.python.org/issue41298 opened by eryksun #41299: Python3 threading.Event().wait time is twice as large as Pytho https://bugs.python.org/issue41299 opened by SD #41300: IDLE: add missing import io in iomenu.py https://bugs.python.org/issue41300 opened by nirinA raseliarison #41303: perf_counter result does not count system sleep time in Mac OS https://bugs.python.org/issue41303 opened by nooB #41305: Add StreamReader.readinto() https://bugs.python.org/issue41305 opened by tontinton #41306: test_tk test_widgets.ScaleTest fails with Tk 8.6.10 https://bugs.python.org/issue41306 opened by felixonmars #41307: "email.message.Message.as_bytes": fails to correctly handle " https://bugs.python.org/issue41307 opened by dmaurer #41308: socket.connect() slow to time out on Windows https://bugs.python.org/issue41308 opened by steve.dower #41309: test_subprocess.test_pause_reading timing out randomly on Wind https://bugs.python.org/issue41309 opened by steve.dower #41310: micro-optimization: increase our float parsing speed by Nx https://bugs.python.org/issue41310 opened by gregory.p.smith #41311: Add a function to get a random sample from an iterable (reserv https://bugs.python.org/issue41311 opened by oscarbenjamin #41314: __future__ doc and PEP 563 conflict https://bugs.python.org/issue41314 opened by wyz23x2 #41315: Add mathematical functions as wrappers to decimal.Decimal meth https://bugs.python.org/issue41315 opened by Jean Abou Samra #41316: tarfile: Do not write full path in FNAME field https://bugs.python.org/issue41316 opened by ArtemSBulgakov #41317: sock_accept() does not remove server socket reader on cancella https://bugs.python.org/issue41317 opened by alex.gronholm #41318: Better error message of "Cannot recover from stack overflow." https://bugs.python.org/issue41318 opened by thyyyy #41320: async process closing after event loop closed https://bugs.python.org/issue41320 opened by kcwu #41321: Calculate timestamp is wrong in datetime.datetime https://bugs.python.org/issue41321 opened by dh4931 #41322: unittest: Generator test methods will always be marked as pass https://bugs.python.org/issue41322 opened by defreng #41323: Perform "peephole" optimization directly on control-flow graph https://bugs.python.org/issue41323 opened by Mark.Shannon #41324: Add a minimal decimal capsule API https://bugs.python.org/issue41324 opened by skrah #41325: Document addition of `mock.call_args.args` and `mock.call_args https://bugs.python.org/issue41325 opened by uspike Most recent 15 issues with no replies (15) ========================================== #41325: Document addition of `mock.call_args.args` and `mock.call_args https://bugs.python.org/issue41325 #41323: Perform "peephole" optimization directly on control-flow graph https://bugs.python.org/issue41323 #41320: async process closing after event loop closed https://bugs.python.org/issue41320 #41318: Better error message of "Cannot recover from stack overflow." https://bugs.python.org/issue41318 #41314: __future__ doc and PEP 563 conflict https://bugs.python.org/issue41314 #41309: test_subprocess.test_pause_reading timing out randomly on Wind https://bugs.python.org/issue41309 #41308: socket.connect() slow to time out on Windows https://bugs.python.org/issue41308 #41303: perf_counter result does not count system sleep time in Mac OS https://bugs.python.org/issue41303 #41298: Enable handling logoff and shutdown Windows console events https://bugs.python.org/issue41298 #41294: Allow '__qualname__' to be an instance of 'DynamicClassAttribu https://bugs.python.org/issue41294 #41292: Dead link in Windows FAQ https://bugs.python.org/issue41292 #41283: The parameter name for imghdr.what in the documentation is wro https://bugs.python.org/issue41283 #41281: Wrong/missing code formats in datetime documentation https://bugs.python.org/issue41281 #41279: Convert StreamReaderProtocol to a BufferedProtocol https://bugs.python.org/issue41279 #41277: documentation: os.setxattr() errno EEXIST and ENODATA https://bugs.python.org/issue41277 Most recent 15 issues waiting for review (15) ============================================= #41325: Document addition of `mock.call_args.args` and `mock.call_args https://bugs.python.org/issue41325 #41324: Add a minimal decimal capsule API https://bugs.python.org/issue41324 #41323: Perform "peephole" optimization directly on control-flow graph https://bugs.python.org/issue41323 #41316: tarfile: Do not write full path in FNAME field https://bugs.python.org/issue41316 #41309: test_subprocess.test_pause_reading timing out randomly on Wind https://bugs.python.org/issue41309 #41305: Add StreamReader.readinto() https://bugs.python.org/issue41305 #41295: CPython 3.8.4 regression on __setattr__ in multiinheritance wi https://bugs.python.org/issue41295 #41292: Dead link in Windows FAQ https://bugs.python.org/issue41292 #41283: The parameter name for imghdr.what in the documentation is wro https://bugs.python.org/issue41283 #41281: Wrong/missing code formats in datetime documentation https://bugs.python.org/issue41281 #41279: Convert StreamReaderProtocol to a BufferedProtocol https://bugs.python.org/issue41279 #41273: asyncio: proactor read transport: use recv_into instead of rec https://bugs.python.org/issue41273 #41270: NamedTemporaryFile is not its own iterator. https://bugs.python.org/issue41270 #41262: Convert memoryview to Argument Clinic https://bugs.python.org/issue41262 #41259: Find adverbs is not correct on the documentation https://bugs.python.org/issue41259 Top 10 most discussed issues (10) ================================= #41282: Deprecate and remove distutils https://bugs.python.org/issue41282 15 msgs #41305: Add StreamReader.readinto() https://bugs.python.org/issue41305 9 msgs #41300: IDLE: add missing import io in iomenu.py https://bugs.python.org/issue41300 8 msgs #41278: IDLE: Clarify some completion details in doc https://bugs.python.org/issue41278 7 msgs #41295: CPython 3.8.4 regression on __setattr__ in multiinheritance wi https://bugs.python.org/issue41295 7 msgs #41299: Python3 threading.Event().wait time is twice as large as Pytho https://bugs.python.org/issue41299 7 msgs #41311: Add a function to get a random sample from an iterable (reserv https://bugs.python.org/issue41311 5 msgs #41210: Docs: More description of reason about LZMA1 data handling wit https://bugs.python.org/issue41210 4 msgs #41220: add optional make_key argument to lru_cache https://bugs.python.org/issue41220 4 msgs #41233: Missing links to errnos on Built-in Exceptions page https://bugs.python.org/issue41233 4 msgs Issues closed (36) ================== #20171: Derby #2: Convert 115 sites to Argument Clinic in Modules/_cur https://bugs.python.org/issue20171 closed by serhiy.storchaka #20175: Derby #6: Convert 50 sites to Argument Clinic across 8 files https://bugs.python.org/issue20175 closed by serhiy.storchaka #20179: Derby #10: Convert 50 sites to Argument Clinic across 4 files https://bugs.python.org/issue20179 closed by serhiy.storchaka #20181: Derby #12: Convert 50 sites to Argument Clinic across 4 files https://bugs.python.org/issue20181 closed by serhiy.storchaka #22194: access to cdecimal / libmpdec API https://bugs.python.org/issue22194 closed by skrah #31844: HTMLParser: undocumented not implemented method https://bugs.python.org/issue31844 closed by berker.peksag #37237: python 2.16 from source on Ubuntu 18.04 https://bugs.python.org/issue37237 closed by benjamin.peterson #39017: Infinite loop in the tarfile module https://bugs.python.org/issue39017 closed by larry #39280: Don't allow datetime parsing to accept non-Ascii digits https://bugs.python.org/issue39280 closed by cool-RR #40150: (minor) mismatched argument in overlapped_RegisterWaitWithQueu https://bugs.python.org/issue40150 closed by serhiy.storchaka #40734: /usr/bin surprisingly in sys.path under IDLE https://bugs.python.org/issue40734 closed by terry.reedy #41146: Convert signal.default_int_handler() to Argument Clinic https://bugs.python.org/issue41146 closed by serhiy.storchaka #41187: Convert the _msi module to Argument Clinic https://bugs.python.org/issue41187 closed by serhiy.storchaka #41202: Allow to provide custom exception handler to asyncio.run() https://bugs.python.org/issue41202 closed by aeros #41212: Emoji Unicode failing in standard release of Python 3.8.3 / tk https://bugs.python.org/issue41212 closed by terry.reedy #41228: Fix the typo in the description of calendar.monthcalendar(year https://bugs.python.org/issue41228 closed by terry.reedy #41253: unittest -h shows a flag -s but it doesn't work https://bugs.python.org/issue41253 closed by eric.smith #41257: mimetypes.guess_extension('video/x-matroska') return wrong val https://bugs.python.org/issue41257 closed by ammar2 #41268: 3.9-dev regression? TypeError: exec_module() missing 1 require https://bugs.python.org/issue41268 closed by ned.deily #41274: Better way to random.seed()? https://bugs.python.org/issue41274 closed by rhettinger #41276: Min / Max returns different values depending on parameter orde https://bugs.python.org/issue41276 closed by steven.daprano #41280: lru_cache on 0-arity functions should default to maxsize=None https://bugs.python.org/issue41280 closed by rhettinger #41284: High Level API for json file parsing https://bugs.python.org/issue41284 closed by serhiy.storchaka #41285: memoryview does not support subclassing https://bugs.python.org/issue41285 closed by skrah #41286: Built-in platform module does not offer to check for processor https://bugs.python.org/issue41286 closed by ammar2 #41288: Pickle crashes unpickling invalid NEWOBJ_EX opcode https://bugs.python.org/issue41288 closed by ned.deily #41289: '%' character in help= for argparse causes ValueError: incompl https://bugs.python.org/issue41289 closed by Neil Godber #41290: ipaddress module doesn't recognize 100.64.0.0/10 as a private https://bugs.python.org/issue41290 closed by SilentGhost #41291: Race conditions when opening and deleting a file on Mac OS X https://bugs.python.org/issue41291 closed by ned.deily #41296: unittest.mock: patched mocks do not propagate calls to parent https://bugs.python.org/issue41296 closed by xtreak #41301: Assignment operation of list is not working as expected https://bugs.python.org/issue41301 closed by steven.daprano #41302: _decimal failed to build with system libmpdec 2.5 https://bugs.python.org/issue41302 closed by skrah #41304: [CVE-2020-15801] python 38 embed ignore python38._pth file on https://bugs.python.org/issue41304 closed by steve.dower #41312: add !p to pprint.pformat() in str.format() an f-strings https://bugs.python.org/issue41312 closed by rhettinger #41313: sys.setrecursionlimit: OverflowError still raised when int lim https://bugs.python.org/issue41313 closed by mark.dickinson #41319: IDLE 3.8 can not save and run this file https://bugs.python.org/issue41319 closed by terry.reedy

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Re: PEP 622 constant value syntax idea
by Eric Nieuwland 16 Jul '20

16 Jul '20

> From: Baptiste Carvello <devel2020(a)baptiste-carvello.net> > Subject: [Python-Dev] Re: PEP 622 constant value syntax idea > > What about simply "is", which is already a keyword? > > AFAIK "is" has no meaning as a prefix operator as of now, so hopefully > it would not make the grammar ambiguous (how can one check that for sure?). > > match color: > case is RED: > print("red") > case is BLUE: > print("blue") > case other: > print(f"unknown color {other}") > > or with Rhodri James' example: > > match value: > case is x: > print("value matches") > case Point(is x, y): > print("value matches x, y captured") > case Line(Point(is x1, y1), Point(x2, is y2)): > print("wouldn't call that pretty, but not ugly either") > > > Cheers, > Baptiste > > P.S.: granted, it could mislead some users into thinking that the > comparison is done with "is" instead of "=="; but then, patterns are > special in many ways, users will have to just learn them… That is exactly why I think you should make the special things special and keep the familiar things as you know them. So constants and variables like they are in other uses and matched values/patterns using a special construction/syntax. And we don’t need the catch all case if we would have the IMHO more familiar: match Color(…) as color: case RED: print(f”{color} is red") case BLUE: print(f”{color} is blue”) else: print(f"unknown color {color}”) thus eliminating the whole ‘case <var>’ issue.

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Problems with python and Geany?
by arajgure＠sevenmentor.com 16 Jul '20

16 Jul '20

So I have recently purchased a rapsberry pi in hope that it will ease me in to programming and learn a bit more about computing. I was reading an article in pc pro about creating a game using python so thought I would give it a shot. However, when I try to execute on Geany I keep getting the same message : "09:13:05: Failed to execute "C:\Python27\python "raspberry.py"" (start-script could not be created: Failed to create file: Permission denied)" I've been searching google and forums for answers as I cannot see why this is not working.... Any ideas? Anyone?! https://www.sevenmentor.com/best-python-classes-in-pune.php

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I plan to accept PEP 623 "Remove wstr from Unicode" next week
by Victor Stinner 15 Jul '20

15 Jul '20

Hi, As the PEP delegate of the PEP 623, I plan to accept PEP 623 "Remove wstr from Unicode" next week. As far as I know, all previous remarks have been taken in account. https://www.python.org/dev/peps/pep-0623/ I worked with INADA-san to adjust his PEP 623 plan: * DeprecationWarning warnings will be emitted as soon as Python 3.10 to help developers detect the deprecation at runtime, rather than only announcing the deprecation with compiler warnings and in the documentation. * Developers have two Python releases (3.10 and 3.11) with these runtime warnings before functions are removed * The PEP lists all APIs which will be removed in Python 3.12. * The PEP gives links to past discussions and issues. About the "size > 0" condition in "PyUnicode_FromUnicode(NULL, size) and PyUnicode_FromStringAndSize(NULL, size) emit DeprecationWarning when size > 0". INADA-san made sure that Cython avoids PyUnicode_FromUnicode(NULL, 0) to create an empty string: it's already fixed! The fix will be part of the next Cython 0.29.x release (it should be 0.29.21). But it will take time until popular extension modules using Cython will distribute a new release with updated generated C code. INADA-san checked popular PyPI projects. The majority of projects impacted by the PEP are using Cython and so are easy to fix: just regenerate C code with the fixed Cython. He added: "A few projects, pyScss and Genshi are not straightforward. But it is not too hard and I will help them." We have time before Python 3.12 final to update these projects. The PEP 623 is backward incompatible on purpose. If needed, it remains possible to use a single code base working on Python 2.7 and Python 3.12 using #ifdef. But Python 3.12 will not be released before 2023: three years after Python 2 end of life, so I think that it's reasonable for extension modules to consider dropping Python 2 support to implement the PEP 623 (stop using these deprecated C APIs). Victor -- Night gathers, and now my watch begins. It shall not end until my death.

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BPO-41182 - Update
by Abhijeet Kasurde 14 Jul '20

14 Jul '20

Hi Team, I am waiting for a review on https://github.com/python/cpython/pull/21257. It would be great if someone can take a look at it and move PR forward. Thanks in advance. -- Thanks, Abhijeet Kasurde

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[RELEASE] Python 3.8.4 is now available
by Łukasz Langa 13 Jul '20

13 Jul '20

Python 3.8.4 is the fourth maintenance release of Python 3.8. Go get it here: https://www.python.org/downloads/release/python-384/ <https://www.python.org/downloads/release/python-384/> Maintenance releases for the 3.8 series will continue at regular bi-monthly intervals, with 3.8.5 planned for mid-September 2020. What’s new? The Python 3.8 series is the newest feature release of the Python language, and it contains many new features and optimizations. See the “What’s New in Python 3.8 <https://docs.python.org/3.8/whatsnew/3.8.html>” document for more information about features included in the 3.8 series. This is the first bugfix release that is considerably smaller than the previous three. There’s almost 20% fewer changes at 162 commits than the average of previous three bugfix releases. Detailed information about all changes made in version 3.8.4 specifically can be found in its change log <https://docs.python.org/release/3.8.4/whatsnew/changelog.html#python-3-8-4-…>. Note that compared to 3.8.3, version 3.8.4 also contains the changes introduced in 3.8.4rc1. We hope you enjoy Python 3.8! Thanks to all of the many volunteers who help make Python Development and these releases possible! Please consider supporting our efforts by volunteering yourself or through organization contributions to the Python Software Foundation. Your friendly release team, Ned Deily @nad <https://discuss.python.org/u/nad> Steve Dower @steve.dower <https://discuss.python.org/u/steve.dower> Łukasz Langa @ambv <https://discuss.python.org/u/ambv>

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PEP 622 and fitting the pieces together
by Paul Svensson 12 Jul '20

12 Jul '20

Having followed this discussion for a while, I'm trying to put my finger on why I feal uneasy about it. The major features I see in this proposal are: * New syntax for trying multiple assignments until one matches. * Extending destructuring assignment to match constants in the LHS. * Adding syntax to tell constants from targets. * Extending destructuring assignment to match isinstance and properties. * Making _ a special variable that doesn't always gets assigned a value. I see the other features are only discussed as part of the first one. I think each feature has (some) value on its own, could be implemented without the others, so really should stand or fall on it's own merit. And there I found the root of my uneasiness - the supporting cast is stronger than the main actor. To me, that suggest we should change focus, to look at the usefulness of these extensions in themselves, relegating the match/case statement to syntactic sugar. /Paul

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