• Posts
  • RSS
  • ◂◂RSS
  • Contact

  • Python Navigation in Emacs

    April 28th, 2017
    code, python, tech
    I'm now working full time in python in a medium-sized existing codebase, and I've started using jedi-mode for code navigation. What I really like about this package is that I can press C-c . to jump to the definition of something, and then C-c , to jump back again. What's especially cool about jedi is that it parses the python syntax tree, understands type hints, and can show you the definitions of things like attributes on arbitrary objects. Consider:

    class Foo():
      def a():
        return 'foo'
    class Bar():
      def a():
        return 'bar'
    def baz(b: Foo) -> str:
      return b.a
    

    In a simple tags or dumb-jump system there's no way to know that b.a is Foo.a and not Bar.a, but jedi-mode understands the python and jumps to the right place.

    What I don't like about jedi-mode is that it also turns on other distracting things that get in the way of trying to write. If you hold the cursor still it pops up "quick help" that obscures the code below:

    If you start to type something it recognizes it offers a completion, and if you press the wrong key you'll accidentally accept the completion:

    And if you type something ambigous it can do both frustrating things at once:

    I put up with this for a surprisingly long time before looking into fixing it, but these can be disabled. The key thing is that jedi-mode turns on auto-complete-mode, and it's auto-complete that's responsible for most of the behavior I don't like. So: here's how to turn on jedi in a non-instrusive way:

    ; move quick-help tooltips to the minibuffer
    (setq jedi:tooltip-method nil)
    
    ; don't auto-complete unless requested
    (setq ac-auto-start nil)
    (setq ac-auto-show-menu nil)
    (define-key ac-mode-map (kbd "M-TAB") 'auto-complete)
    
    (add-hook 'python-mode-hook 'jedi:setup)
    

    I'm pretty happy, but there are still two things I'd like:

    • C-c , on an empty stack should bring up a list of places a thing is used. That is, places where C-c . would bring you here.
    • Automated refactoring: rope has fallen way behind and can't handle python 3 codebases well. I'd love to be able to write "turn all calls to package.foo(...) into package._foo(...)" rules and have jedi automatically apply them.

    Comment via: google plus, facebook

    Recent posts on blogs I like:

    Be less scared of overconfidence

    deferring to markets • deferring to experts • deferring to low-information heuristics • why they fail • blindness to outliers • what to do instead

    via benkuhn.net November 30, 2022

    Corncob Dolls

    I went to a farm and at the farm I got to see a corncrib and the corn that had fell out of the corncrib that no one wanted I got to use my fingers to take off the corn kernels and once the cobs were empty I put them in a bag and then once I got back to the…

    via Anna Wise's Blog Posts November 7, 2022

    Light Switch

    When I got my loft bed it was just so annoying every morning to have to get out of bed, climb down the ladder, turn the light on, and climb back up, just so I could see stuff. I decided to make a string for my light switch because I really wanted to be abl…

    via Lily Wise's Blog Posts November 7, 2022

    more     (via openring)


  • Posts
  • RSS
  • ◂◂RSS
  • Contact