#269: Get Rich and replace your cat

Watch the live stream:

Play on YouTube

Watch the live stream replay

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:

• Black is no longer in beta! Version 22.1.0 is out 🥳
• PyCascades 2022 reminder (remote!)

Joke: