Emacs Python Demo

Setup

One-off

• Install use-package in emacs.

• Restarting emacs should then automatically install all other required packages.

• Opening a Python file for the first time should trigger elpy to create a virtual environment at ~/.emacs.d/elpy/rpc-venv. You may be prompted to automatically install a number of tools into this environment. I prefer to decline and install my preferred tools manually with:

  source ~/.emacs.d/elpy/rpc-venv/bin/activate
  pip install black jedi rope flake8 flake8-isort pylint mypy
  deactivate
  

• Install direnv - see instructions for your system. Be sure to install the hook for your shell.

Per project

• Create project virtual environment - python -m venv .venv

• Create and activate a .envrc:

  cat <<EOF > .envrc
  source .venv/bin/activate
  unset PS1
  EOF
  direnv allow
  

  The virtual environment should now be active.

• Install project dependencies:

  pip install -r requirements.txt
  

• Create a .dir-locals.el (if relevant), e.g.:

  cat <<EOF > .dir-locals.el
  ((nil . (
  	 (project-uses-black . t)
  	 (elpy-test-runner . elpy-test-pytest-runner)
           )
        )
   )
  EOF
  

Functionality

• Standard IDE-like
  • Auto-completion
  • Auto-formatting
  • Documentation lookup
  • Goto definition/find references
  • Execute code snippets
  • Linting support (with multiple tools)
  • Test execution
  • Debugging
  • Refactoring
• Virtual environment support
  • Automatic activation
  • Switch between multiple active projects
• Project level configuration
  • Environment variables via .envrc
  • Emacs configuration via .dir-locals.el