Enable Elixir code folding in Doom Emacs

Code folding recently landed in Elixir’s LSP implementation 🎉 and if you want to give it a try in Doom Emacs, here are the steps needed:

Ensure you have the latest Elixir LSP #

Support just hit master and has not been pushed in a tagged release. Make sure you have updated your install.

If you have not installed Elixir LSP before – that is outside the scope of this article – but the gist is something like:

git clone https://github.com/elixir-lsp/elixir-ls.git
cd elixir-ls
mix deps.get
mix compile
mix elixir_ls.release

Disable existing fold layer #

Doom Emacs has a custom folding layer that marries hideshow, vimish-fold, and outline-minor-mode. Since we need to use origami to get LSP-backed folding support, it is best to comment out the existing folding layer and avoid any potential conflicts.

This is a safety measure, I am not sure if these things can co-exist. Feel free to try and report back in #emacs in the Elixir community Slack.

;; ~/.doom.d/init.el

(doom!
  ;; ... more config ...

  :editor
  ;;fold              ; (nigh) universal code folding

  ;; ... more config ...

Enable code folding for the LSP layer with Origami #

Add the lsp-origami to the doom packages:

;; ~/.doom.d/packages.el

(package! lsp-origami)

Enable code folding with lsp and set up package hooks:

;; ~/.doom.d/config.el

;; Enable folding
(setq lsp-enable-folding t)

;; Add origami and LSP integration
(use-package! lsp-origami)
(add-hook! 'lsp-after-open-hook #'lsp-origami-try-enable)

Then run doom sync to install the new packages and remove the old one.

Testing it out #

Open up an elixir file and use all the usual keybindings z c to collapse, z o to open, z r to open recursively. You can discover all the commands running SPC : and fuzzy searching for commands starting with fold or origami

Bugs #

If you run into any bugs with the new folding feature, report it upstream to the Elixir Language Server project.