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Episode #269: Get Rich and replace your cat

Published Thu, Feb 3, 2022, recorded Wed, Feb 2, 2022.


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About the show

Sponsored by Datadog: pythonbytes.fm/datadog

Special guest: Luciana and Brett Cannon

Brian #1:rich-cli

  • suggested by Lance Reinsmith
  • rich on the command line.
  • why?
    • syntax highlighting
      • rich example.py
      • rich -m README.md use -m for markdown
        • why Will? .md seems clear enough to me.
    • comes with themes. ex: --theme monokai
    • formats json, --json or -j
  • and a bunch of other features I probably won’t use, but you might.
    • alignment, maybe
    • width, yeah, I’ll probably use -w
    • a bunch more
  • In my .zshrc: alias cat='rich --theme monokai'
    • after pipx install rich-cli
    • feel free to tell me that I shouldn’t used cat for looking at file contents. (although, why not?)
    • I’m not, I’m using rich. :)

Luciana #2: debugpy - a debugger for Python

  • The debugger we use in the Python extension for VS Code
  • Super heplful features that can save up a lot of time and a lot of folks don’t seem to know about:
    • Conditional breakpoints
      • Helpful when you want the code to break only on a specific condition
      • e.g. # of execution times, or when an expression is true
    • Debug console
      • Helpful for quick testing using the context of the program at the breakpoint
      • Temp edits on variable values, expresison evaluation, etc.
    • Jump to Cursor (a.k.a. Set Next Statement)
      • Control on what is the next line the debugger will execute
      • Including previously executed lines

Brian #3: Documentation unit tests

  • Simon Willison
  • Post talking about using pytest and tests to check documentation.
  • Simon has test code that
    • introspects the code
    • introspects the docs
    • then makes sure some items are definitely in the docs
  • This is used in Datasette, so you can look at the example in the repo
  • What’s tested:
    • config options are all documented
    • plugin hooks are documented
    • views are all documented
  • Cool use of parametrize to generate test cases based on introspection
  • Nice use of fixtures
  • Very cool idea

Luciana #4: PEP 673 — Self Type

  • Heard from Brett Cannon that it has been accepted!
  • Interesting for me as I’m learning more about types in Python
  • Adds a way to annotate methods that return an instance of their class
  • Particularly interesting for subclasses, exemple they gave: from __future__ import annotations class Shape:
def set_scale(self, scale: float) -> Shape:
            self.scale = scale
            return self

     class Circle(Shape):
        def set_radius(self, r: float) -> Circle:
            self.radius = r
            return self

    Circle().set_scale(0.5)  # *Shape*, not Circle
    Circle().set_scale(0.5).set_radius(2.7)

    # => Error: Shape has no attribute set_radius

Extras

Luciana:

Joke:


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