#96: Python Language Summit 2018

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Brian #1: Plumbum: Shell Combinators and More

• Toolbox of goodies to do shell-like things from Python.
• “The motto of the library is “Never write shell scripts again”, and thus it attempts to mimic the shell syntax (shell combinators) where it makes sense, while keeping it all Pythonic and cross-platform.”

Example:

>>> from plumbum.cmd import grep, wc, cat, head
>>> chain = ls["-a"] | grep["-v", "\\.py"] | wc["-l"]
>>> print chain
/bin/ls -a | /bin/grep -v '\.py' | /usr/bin/wc -l
>>> chain()
u'13\n'
>>> ((cat < "setup.py") | head["-n", 4])()
u'#!/usr/bin/env python\nimport os\n\ntry:\n'
>>> (ls["-a"] > "file.list")()
u''
>>> (cat["file.list"] | wc["-l"])()
u'17\n'

Michael #2: Windows 10 Linux subsystem for Python developers

• via Marcus Sherman
• “One of the hardest days in teaching introduction to bioinformatics material is the first day: Setting up your machine.”
• While I have seen a very large bias towards Macs in academia, there are plenty of people that keep their Windows machines as a badge of pride... Marcus included.
• Even though Anaconda is cross platform and helpful, how does this work on Windows?
  • python3 -m venv .env and source .env/bin/activate?
  • Spoiler alert: Not well.
• Step by step getting Ubuntu on Windows
• Shows how to setup an x-server

Brian #3: Type hints cheat sheet (Python 3)

• Do you remember how to type hint duck types?
  • Something accessed like an array (list or tuple or …) and holds strings → Sequence[str]
  • Something that works like a dictionary mapping integers to strings → Mapping[int, str]
• As I’m adding more and more typing to interface functions, I keep this cheat sheet bookmarked.

Michael #4: Python driving new languages

• Here are five predictions for what programming will look like 10 years from now.
  • Programming will be more abstract
  • Trends like serverless technologies, containers, and low code platforms suggest that many developers may work at higher levels of abstraction in the future
  • AI will become part of every developer's toolkit—but won't replace them
    • A universal programming language will arise
  • To reap the benefits of emerging technologies like AI, programming has to be easy to learn and easy to build upon
  • "Python may be remembered as being the great-great-great grandmother of languages of the future, which underneath the hood may look like the English language, but are far easier to use,"
    • Every developer will need to work with data
    • Programming will be a core tenet of the education system

Brian #5: asyncio documentation rewritten from scratch

• twitter thread by Yury Selivanov‏
  • “Big news! asyncio documentation has been rewritten from scratch! Read the new version here: https://docs.python.org/3/library/asyncio.html …. Huge thanks to @WillingCarol, @elprans, and @andrew_svetlov for support, ideas, and reviews!’
  • “BTW, this is just the beginning. We'll continue to refine and update the documentation. Next up is adding two tutorials: one teaching high-level concepts and APIs, and another teaching how to use protocols and transports. A section about asyncio architecture is also planned.”
  • “And this is just the beginning not only for asyncio documentation, but for asyncio itself. Just for Python 3.8 we plan to add:
    • new streaming API
    • TaskGroups and cancel scopes
    • Supervisors and tracing API
    • new SSL implementation
    • many usability improvements”

Michael #6: The 2018 Python Language Summit

• Here are the sessions:
  • Subinterpreter support for Python: a way to have a better story for multicore scalability using an existing feature of the language.
    • Subinterpreters will allow multiple Python interpreters per process and there is the potential for zero-copy data sharing between them.
    • But subinterpreters share the GIL, so that needs to be changed in order to make it multicore friendly.
  • Modifying the Python object model: looking at changes to CPython data structures to increase the performance of the interpreter.
    • via Instagram and Carl Shapiro
    • By modifying the Python object model fairly substantially, they were able to roughly double the performance
    • A little controversial
    • Shapiro's overall point was that he felt Python sacrificed its performance for flexibility and generality, but the dynamic features are typically not used heavily in performance-sensitive production workloads.
  • A Gilectomy update: a status report on the effort to remove the GIL from CPython.
    • Larry Hastings updated attendees on the status of his Gilectomy project.
    • Since his status report at last year's summit, little has happened, which is part of why the session was so short. He hasn't given up on the overall idea, but it needs a new approach.
  • Using GitHub Issues for Python: a discussion on moving from bugs.python.org to GitHub Issues.
    • Mariatta Wijaya described her reasoning for advocating moving Python away from its current bug tracker to GitHub Issues.
    • it would complete Python's journey to GitHub that started a ways back.
  • Shortening the Python release schedule: a discussion on possibly changing from an 18-month to a yearly cadence.
    • The Python release cycle has an 18-month cadence; a new major release (e.g. Python 3.7) is made roughly on that schedule.
    • But Łukasz Langa, who is the release manager for Python 3.8 and 3.9, would like to see things move more quickly—perhaps on a yearly cadence.
  • Unplugging old batteries: should some older, unloved modules be removed from the standard library?
    • Python is famous for being a "batteries included" language—its standard library provides a versatile set of modules with the language
    • There may be times when some of those batteries have reached their end of life.
    • Christian Heimes wanted to suggest a few batteries that may have outlived their usefulness and to discuss how the process of retiring standard library modules should work.
  • Linux distributions and Python 2: the end of life for Python 2 is coming, what distributions are doing to prepare.
    • Christian Heimes wanted to suggest a few batteries that may have outlived their usefulness and to discuss how the process of retiring standard library modules should work.
    • To figure out how to help the Python downstreams so that Python 2 can be fully discontinued.
  • Python static typing update: a look at where static typing is now and where it is headed for Python 3.7.
    • Started things off by talking about stub files, which contain type information for libraries and other modules.
    • Right now, static typing is only partially useful for large projects because they tend to use a lot of packages from the Python Package Index (PyPI), which has limited stub coverage. There are only 35 stubs for third-party modules in the typeshed library, which is Python's stub repository.
    • He suggested that perhaps a centralized library for stubs is not the right development model. Some projects have stubs that live outside of typeshed, such as Django and SQLAlchemy.
    • PEP 561 ("Distributing and Packaging Type Information") will provide a way to pip install stubs from packages that advertise that they have them.
  • Python virtual environments: a short session on virtual environments and ideas for other ways to isolate local installations.
    • Steve Dower brought up the shortcomings of Python virtual environments, which are meant to create isolated installations of the language and its modules.
    • Thomas Wouters defended virtual environments in a response: The correct justification is that for the average person, not using a virtualenv all too soon creates confusion, pain, and very difficult to fix breakage. Starting with a virtualenv is the easiest way to avoid that, at very little cost.
    • But Beazley and others (including Dower) think that starting Python tutorials or training classes with a 20-minute digression on setting up a virtual environment is wasted time.
  • PEP 572 and decision-making in Python: a discussion of the controversy around PEP 572 and how to avoid the thread explosion that it caused in the future.
    • The "PEP 572 mess" was the topic of a 2018 Python Language Summit session led by benevolent dictator for life (BDFL) Guido van Rossum.
  • Getting along in the Python community: trying to find ways to keep the mailing list welcoming even in the face of rudeness.
    • About tkinter…
  • Mentoring and diversity for Python: a discussion on how to increase the diversity of the core development team.
    • Victor Stinner outlined some work he has been doing to mentor new developers on their path toward joining the core development ranks
    • Mariatta Wijaya gave a very personal talk that described the diversity problem while also providing some concrete action items that the project and individuals could take to help make Python more welcoming to minorities.

Extras

Listener feedback: CUDA is NVidia only, so no MacBook pro unless you have a custom external GPU.