Mailman 3 September 2020 - Python-Dev

Ask a Core Dev Anything! (You can even ask Guido!)
by Mariatta Sept. 24, 2020

Sept. 24, 2020

Made you look! [image: :smile:] Hello Python community! Next month, from October 19-23, Python core developers will be participating in our annual weeklong core dev sprint. As part of the sprint, we will be hosting a Q&A session with participating Python core developers as a way for us to connect and engage with the wider Python community. We would like the wide Python community members (you) to participate and ask a core dev any questions about Python. https://app.sli.do/event/d4ifvw2o … [View More]

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[RELEASE] Python 3.8.6 is now available
by Łukasz Langa Sept. 24, 2020

Sept. 24, 2020

Python 3.8.6 is the sixth maintenance release of Python 3.8. Go get it here: https://www.python.org/downloads/release/python-386/ <https://www.python.org/downloads/release/python-386/> Maintenance releases for the 3.8 series will continue at regular bi-monthly intervals, with 3.8.7 planned for mid-November 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 … [View More]

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Understanding why object defines rich comparison methods
by Steven D'Aprano Sept. 23, 2020

Sept. 23, 2020

Why does `object` define rich comparison dunders `__lt__` etc? As far as I can tell, `object.__lt__` etc always return NotImplemented. Merely inheriting from object isn't enough to have comparisons work. So why do they exist at all? Other "do nothing" dunders such as `__add__` aren't defined. I've tried searching for answers, and looked at the source code for rich comparisons here: https://github.com/python/cpython/blob/3.8/Objects/object.c read the information here and in the PEP: … [View More]

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Tagged pointer experiment: need help to optimize
by Victor Stinner Sept. 23, 2020

Sept. 23, 2020

Hi, I need to help to attempt to optimize my experimental CPython fork which uses tagged pointers. When I proposed my PEP 620 "Hide implementation details from the C API", I was asked about a proof that the PEP unlocks real optimization possibilities. So I wrote an implementation of tagged pointers: https://github.com/vstinner/cpython/pull/6 The main benefit is the memory usage. For example, list(range(200)) uses 1656 bytes instead of 7262 (4x less memory). Sadly, my current simple … [View More]

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unable to create PR on github
by Ethan Furman Sept. 23, 2020

Sept. 23, 2020

The green "create pull request" button is greyed out. I've tried reselecting the repos and branches, logging out and in, navigating to that screen via my own repository -- nothing is working. Any ideas? Thanks. -- ~Ethan~

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Re: PEP 622 version 2 (Structural Pattern Matching)
by Jens Gåsemyr Magnus Sept. 23, 2020

Sept. 23, 2020

It would be fantastic if these were expressions rather than statements. Imagine being able to write things like: ```python @memoized def fibonacci(n): match n: case 0: (return/yield?) 0 case 1: 1 case _: fibonacci(n - 2) + fibonacci(n - 1) ``` Obviously this could be written easily with an if statement, and might not be the best example. But I’ve often encountered situations where I wish I had semantics like this. Jens -------… [View More]

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Enum and the Standard Library
by Ethan Furman Sept. 22, 2020

Sept. 22, 2020

As you may have noticed, Enums are starting to pop up all over the stdlib [1]. To facilitate transforming existing module constants to IntEnums there is `IntEnum._convert_`. In Issue36548 [2] Serhiy modified the __repr__ of RegexFlag: >>> import re >>> re.I re.IGNORECASE I think for converted constants that that looks nice. For anyone that wants the actual value, it is of course available as the `.value` attribute: >>> re.I.value 2 I'm … [View More]

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Hygenic macros PEP.
by Mark Shannon Sept. 19, 2020

Sept. 19, 2020

Hi all, I'd like to propose a new PEP for hygienic macros. I'm attempting to reduce the controversy and pain of adding new syntax to Python, ... by adding new syntax. That might sound silly, but I hope to persuade that it isn't. Adding a new feature to the language is always controversial. Before a new module or functionality is added to the standard library, it must usually prove itself as a package on PyPI. (Not always the same package, the value of dataclasses was demonstrated by "… [View More]

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The Python documentation is now compatible with Sphinx 3.2 and newer
by Victor Stinner Sept. 19, 2020

Sept. 19, 2020

Hi, The Python 3.8, 3.9 and 3.10 documentation can now be built with Sphinx 3.2+, and Sphinx 2 is still supported. Sphinx 3.0 and 3.1 are not supported. On our continuous integration (CI), the Python 3.10 documentation is now built with Sphinx 3 (version 3.2.1), whereas the Python 3.8 and Python 3.9 documentation is still built with Sphinx 2 (just updated to version 2.4.4). Also, the Sphinx version is now only pinned in a single file (Doc/requirements.txt), rather than 3 files (Doc/… [View More]

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Summary of Python tracker Issues
by Python tracker Sept. 18, 2020

Sept. 18, 2020

ACTIVITY SUMMARY (2020-09-11 - 2020-09-18) 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 7675 (-22) closed 45870 (+67) total 53545 (+45) Open issues with patches: 3122 Issues opened (29) ================== #41768: unittest.mock spec calls class properties https://bugs.python.org/issue41768 opened by melwitt #41769: Positional arguments which … [View More]

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