I'm trying to setup Emacs for editing Roc (https://www.roc-lang.org/) source code. I have an LSP server for Roc and tree-sitter parser for Roc installed.

Unfortunately I failed to find tree-sitter documentation for absolute beginners. Initially my configuration was copy-pasted from this article and other examples all over the Internet:

;;; Roc (define-derived-mode roc-mode fundamental-mode "Roc") (add-to-list 'auto-mode-alist '("\\.roc\\'" . roc-mode)) ;; LSP (require 'lsp) (with-eval-after-load 'lsp-mode (add-to-list 'lsp-language-id-configuration '(roc-mode . "roc")) (lsp-register-client (make-lsp-client :new-connection (lsp-stdio-connection "roc_ls") :activation-fn (lsp-activate-on "roc") :server-id 'theme-check))) ;; tree-sitter (require 'treesit) (require 'tree-sitter) (require 'tree-sitter-langs) (defun roc-mode-setup () (interactive) (treesit-parser-create 'roc) (global-tree-sitter-mode) (tree-sitter-hl-mode) (treesit-major-mode-setup)) (tree-sitter-load 'roc "/home/yshirokov/.emacs.d/tree-sitter/libtree-sitter-roc") (add-to-list 'tree-sitter-major-mode-language-alist '(roc-mode . roc)) (add-hook 'roc-mode-hook (lambda () (roc-mode-setup) (setq treesit-font-lock-level 4))) 

Well, with this configuration I have an LSP connection, I can see the types under the cursor in the modeline and can visualize and the syntax tree with treesit-explore-mode. So, both LSP and tree-sitter parser are probably working. But I have no syntax highlighting.

So I added explicit highlighting rules:

;; tree-sitter (require 'treesit) (require 'tree-sitter) (require 'tree-sitter-langs) (defun roc-mode-setup () (interactive) (treesit-parser-create 'roc) (setq-local treesit-font-lock-feature-list '((comment) (keyword))) (defvar roc-font-lock-rules '(:language roc :override t :feature comment '((comment) @font-lock-comment-face) :language roc :override t :feature keyword '((keyword) @font-lock-keyword-face))) (global-tree-sitter-mode) (tree-sitter-hl-mode) (setq-local treesit-font-lock-settings (apply #'treesit-font-lock-rules roc-font-lock-rules)) (treesit-major-mode-setup)) 

But it changed nothing: I still haven't syntax highlighting.

Is it possible to have syntax highlighting for a new language with existing tree-sitter parser? Maybe, there is some step-by-step guide for absolute beginners in tree-sitter mode I missed?