# Eglot based Emacs Python IDE

tags: emacs python

This post is now a bit outdated an updated post is here.

In my Emacs rabbit hole I mentioned in my previous post, I decided to work on improving my Python development workflow. I recently found the Eglot package for running a LSP in Emacs.

The most vanilla setup for Eglot is just M-x eglot in a buffer editing a python file. This works wonderfully if the executable for the Python Language Server (pyls) is found. This works because Eglot defines a list of server programs by default. See this list with M-: eglot-server-programs

## Project Editing

I have a few python virtual/Anaconda environments I like to work with. This is what .dir-locals.el is for:

((python-mode . ((eglot-server-programs    . ((python-mode "/path/to/env/bin/pyls")))
(python-shell-interpreter . "/path/to/env/bin/python")
(company-backends         . (company-capf)))))


where /path/to/env is the path to a virtual environment or Anaconda environment (that of course has python-language-server installed). I also define the path to my Python executable for Emacs' builtin python.el. By default, company-backends includes company-capf for completion-at-point, but I want to make sure that’s what is used because Eglot provides completion-at-point. Eglot also has pyls as a python-mode entry by default, but not to the virtual environment I want to use; this is why I manually define the list of server programs.

When I open a buffer in the project I want to work in, I just call M-x eglot and I’m up and running.

## Non-project Editing

If I’m not editing in a project that has an associated virtual environment, I rely on some “sensible defaults” in my Emacs init file:

(defvar ddavis-default-pyls "~/software/Python/anaconda3/bin/pyls"
"define a default pyls to be used")


This way I have a default pyls executable from my base Anaconda environment (which is potentially different on different machines). I then have a couple of functions to handle default Eglot python environments, where I:

• Make use-package install Eglot if necessary.
• Make sure company-capf is at the front of company-backends.
• Make sure I add an Eglot server program entry pointing to my base Anaconda pyls to the front of the eglot-server-programs list.
(use-package eglot
:ensure t)

(defun dd/python-eglot-enable ()
"set variables and hook for eglot python IDE"
(interactive)
(setq company-backends
(cons 'company-capf
(remove 'company-capf company-backends)))
(python-mode ,ddavis-default-pyls))

I just bring company-capf to the front of the company-backends list, and add my desired Anaconda based pyls to front of the eglot-server-programs` list.