Twelf LSP

An experiment to see if I can make an LSP server for Twelf code.

It currently relies on a version of twelf still in a branch.

Building

npm install
make

Status

• 🚨 definitely not a real usable LSP server yet 🚨
• Can react to textDocument/didChange by parsing the text of the document with twelf.wasm, and storing the results
• Can respond to textDocument/definition by looking for a constructor declaration that contains the current point, and jumping to the previous constructor declaration.

Emacs Testing

I'm testing the mode using eglot in emacs. Here's the elisp I added to my config for that purpose, where ".../twelf-lsp/twelf-lsp" is replaced by the absolute path to the twelf-lsp script in this repository.

(use-package eglot)

(defvar fictional-mode-map
  (let ((map (make-sparse-keymap)))
    map)
  "Keymap for fictional-mode.")


(with-eval-after-load 'eglot
  (add-to-list 'eglot-server-programs
               '(fictional-mode . (".../twelf-lsp/twelf-lsp"))))

;; Define the mode
(define-derived-mode fictional-mode prog-mode "Fictional"
  "A major mode for testing purposes."
  )
(add-to-list 'auto-mode-alist '("\\.fiction\\'" . fictional-mode))

(defun jcreed-fictional-mode-hook ()
  (interactive)
  (eglot)
  (define-key fictional-mode-map (kbd "M-.") 'xref-find-definitions))

(add-hook 'fictional-mode-hook 'jcreed-fictional-mode-hook)