unison-ts-mode.el

;;; unison-ts-mode.el --- Major mode for Unison with tree-sitter support -*- lexical-binding: t; -*-

(require 'treesit)
(require 'rx)

(declare-function treesit-parser-create "treesit.c")
(declare-function treesit-node-type "treesit.c")
(declare-function treesit-node-text "treesit.c")
(declare-function treesit-node-child-by-field-name "treesit.c")
(declare-function treesit-parent-while "treesit.c")
(declare-function treesit-parent-until "treesit.c")
(declare-function treesit-node-prev-sibling "treesit.c")
(declare-function treesit-node-next-sibling "treesit.c")
(declare-function treesit-node-type "treesit.c")
(declare-function treesit-node-text "treesit.c")
(declare-function treesit-node-start "treesit.c")
(declare-function treesit-node-end "treesit.c")
(declare-function treesit-node-child "treesit.c")

(defcustom unison-ts-indent-offset 2
  "Number of spaces for each indentation in `unison-ts-mode'."
  :version "29.1"
  :type 'integer
  :safe 'integerp
  :group 'unison-ts)


(defvar unison-ts--keywords
  '("use" "if" "else" "then" "unique" "structural"))

(defvar unison-ts--brackets
  '("(" ")" "{" "}" "[" "]"))

(defvar unison-ts--treesit-font-lock-settings
  (treesit-font-lock-rules
   :language 'unison
   :feature 'keyword
   `([,@unison-ts--keywords] @font-lock-keyword-face
     (kw_forall) @font-lock-keyword-face
     (unique_kw) @font-lock-keyword-face
     (structural_kw) @font-lock-keyword-face
     (type_kw) @font-lock-keyword-face
     (kw_equals) @font-lock-keyword-face
     (do) @font-lock-keyword-face
     (ability) @font-lock-keyword-face
     (where) @font-lock-keyword-face
     (test_watch_expression (wordy_id) @font-lock-keyword-face)
     (match) @font-lock-keyword-face
     (with) @font-lock-keyword-face
     (cases) @font-lock-keyword-face)

   :language 'unison
   :feature 'comment
   '((comment) @font-lock-comment-face)

   :language 'unison
   :feature 'literal
   '((nat) @font-lock-number-face
     (literal_boolean) @font-lock-constant-face
     [(literal_text) (literal_char)] @font-lock-string-face)

   :language 'unison
   :feature 'operator
   '((operator) @font-lock-operator-face
     (pipe) @font-lock-operator-face
     (arrow_symbol) @font-lock-operator-face
     (">") @font-lock-operator-face
     (or) @font-lock-operator-face
     (and) @font-lock-operator-face
     (bang) @font-lock-operator-face
     (guard (pipe)) @font-lock-operator-face)

   :language 'unison
   :feature 'term
   '(
     (function_application function_name: (path) function_name: (wordy_id)) @font-lock-function-call-face
     (function_application function_name: (wordy_id) @font-lock-function-call-face)
     (type_signature term_name: (path) @function-lock-variable-name-face)
     (type_signature (wordy_id) @font-lock-type-face)
     (term_type (delayed (wordy_id)) @font-lock-type-face)
     (term_definition
      param: (wordy_id) @font-lock-variable-name-face))

   :language 'unison
   :feature 'type
   '((effect (wordy_id)) @font-lock-constant-face
     (ability_declaration type_name: (wordy_id) @font-lock-type-face type_arg: (wordy_id) @font-lock-variable-name-face)
     (type_constructor (type_name (wordy_id) @font-lock-type-face))
     (record_field name: (wordy_id) @font-lock-property-name-face type: (wordy_id) @font-lock-type-face))

   :language 'unison
   :feature 'namespace
   '((path) @font-lock-type-face
    (namespace) @font-lock-type-face

   :language 'unison
   :feature 'extra
   `([,@unison-ts--brackets] @font-lock-bracket-face
     (type_signature_colon) @font-lock-delimiter-face
     (":") @font-lock-delimiter-face)))

;;###autoload
(define-derived-mode unison-ts-mode prog-mode "Unison (TS)"
  "Major mode for Unison files using tree-sitter."
  :group 'unison-ts

  (when (treesit-ready-p 'unison)
    (treesit-parser-create 'unison)

    (setq-local treesit-font-lock-settings unison-ts--treesit-font-lock-settings)
    (setq-local treesit-font-lock-feature-list '((comment term)
                                                 (keyword type namespace)
                                                 (literal operator)
                                                 (extra)))
    (treesit-major-mode-setup)))

;;;###autoload
(progn
  (add-to-list 'auto-mode-alist '("\\.u\\'" . unison-ts-mode)))

(provide 'unison-ts-mode)
;;; unison-ts-mode.el ends here