Highlight regular expressions with tree-sitter-regex grammar

This grammar is bundled in nixos by default and seems good enough for
java regular expressions (the grammar probably supports more features
than java, idk).

Should address issue #11

Author: dannyfreeman

clojure-ts-mode.el

@@ -287,9 +287,35 @@ Only intended for use at development time.")
 
    :feature 'regex
    :language 'clojure
-   :override t
    '((regex_lit marker: _ @font-lock-property-face))
 
+   ;; https://github.com/tree-sitter/tree-sitter-regex/blob/master/grammar.js
+   :feature 'regex
+   :language 'regex
+   :override t
+   '(;; Capturing Groups
+     ((anonymous_capturing_group (["(" ")"]) @font-lock-regexp-grouping-construct))
+     ((non_capturing_group (["(?:" ")"]) @font-lock-regexp-grouping-construct))
+     ((lookahead_assertion (["(?" "=" "!" ")"]) @font-lock-regexp-grouping-construct))
+     ((named_capturing_group (["(?<" ">" ")"]) @font-lock-regexp-grouping-construct))
+     ((group_name) @font-lock-variable-name-face)
+     ;; Character classes
+     ((character_class (["[" "]"]) @font-lock-bracket-face))
+     ((character_class "^" @font-lock-negation-char-face))
+     ((class_range "-" @font-lock-punctuation-face))
+     ;; Quantifiers
+     ([(zero_or_more) (one_or_more) (optional)]) @font-lock-operator-face
+     ((count_quantifier (["{" "}"]) @font-lock-bracket-face))
+     ((count_quantifier "," @font-lock-punctuation-face))
+     ((count_quantifier (decimal_digits) @font-lock-number-face))
+     ;;; Escaping
+     ([(start_assertion) (any_character) (end_assertion)]) @font-lock-operator-face
+     ([(decimal_escape)
+       (identity_escape)
+       (character_class_escape)]) @font-lock-regexp-grouping-backslash
+     ((pattern_character) @font-lock-regexp-face)
+     ([(control_escape) (boundary_assertion)] @font-lock-builtin-face))
+
    :feature 'number
    :language 'clojure
    '((num_lit) @font-lock-number-face)
@@ -597,6 +623,12 @@ See `clojure-ts--standard-definition-node-name' for the implementation used.")
   (interactive)
   (message "clojure-ts-mode (version %s)" clojure-ts-mode-version))
 
+(defvar clojure-ts--treesit-range-settings
+  (treesit-range-rules
+   :embed 'regex
+   :host 'clojure
+   '((regex_lit) @capture)))
+
 ;;;###autoload
 (define-derived-mode clojure-ts-mode prog-mode "Clojure[TS]"
   "Major mode for editing Clojure code.
@@ -607,6 +639,9 @@ See `clojure-ts--standard-definition-node-name' for the implementation used.")
     (treesit-install-language-grammar 'clojure))
   (setq-local comment-start ";")
   (when (treesit-ready-p 'clojure)
+    (when (treesit-ready-p 'regex 'message)
+      (treesit-parser-create 'regex)
+      (setq-local treesit-range-settings clojure-ts--treesit-range-settings))
     (treesit-parser-create 'clojure)
     (setq-local treesit-font-lock-settings (clojure-ts--font-lock-settings)
                 treesit-defun-prefer-top-level t

test/test.clj

@@ -264,7 +264,7 @@ Etiam commodo nulla id risus convallis pharetra. Integer dapibus, eros vitae veh
   (println "Hello, World!"))
 
 (binding [*out* nil]
-  #"regex string"
+  #"^(?<lookup>abc)[0-9]\b$"
   (def #^Typehint x 1)
   (def #^:metadata x 1)
   (def ^Typehint x 2)