;;; json-ts-mode.el --- tree-sitter support for JSON -*- lexical-binding: t; -*- ;; Copyright (C) 2022 Free Software Foundation, Inc. ;; Author : Theodor Thornhill ;; Maintainer : Theodor Thornhill ;; Created : November 2022 ;; Keywords : json languages tree-sitter ;; This file is part of GNU Emacs. ;; This program is free software; you can redistribute it and/or modify ;; it under the terms of the GNU General Public License as published by ;; the Free Software Foundation, either version 3 of the License, or ;; (at your option) any later version. ;; This program is distributed in the hope that it will be useful, ;; but WITHOUT ANY WARRANTY; without even the implied warranty of ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the ;; GNU General Public License for more details. ;; You should have received a copy of the GNU General Public License ;; along with this program. If not, see . ;;; Commentary: ;; ;;; Code: (require 'treesit) (require 'rx) (defcustom json-ts-mode-indent-offset 2 "Number of spaces for each indentation step in `json-ts-mode'." :version "29.1" :type 'integer :safe 'integerp :group 'json) (defvar json-ts-mode--syntax-table (let ((table (make-syntax-table))) ;; Taken from the cc-langs version (modify-syntax-entry ?_ "_" table) (modify-syntax-entry ?$ "_" table) (modify-syntax-entry ?\\ "\\" table) (modify-syntax-entry ?+ "." table) (modify-syntax-entry ?- "." table) (modify-syntax-entry ?= "." table) (modify-syntax-entry ?% "." table) (modify-syntax-entry ?< "." table) (modify-syntax-entry ?> "." table) (modify-syntax-entry ?& "." table) (modify-syntax-entry ?| "." table) (modify-syntax-entry ?` "\"" table) (modify-syntax-entry ?\240 "." table) table) "Syntax table for `json-ts-mode'.") (defvar json-ts--indent-rules `((json ((node-is "}") parent-bol 0) ((node-is ")") parent-bol 0) ((node-is "]") parent-bol 0) ((parent-is "object") parent-bol json-ts-mode-indent-offset)))) (defvar json-ts-mode--font-lock-settings (treesit-font-lock-rules :language 'json :feature 'bracket '(["[" "]" "{" "}"] @font-lock-bracket-face) :language 'json :feature 'constant '([(null) (true) (false)] @font-lock-constant-face) :language 'json :feature 'delimiter '(["," ":"] @font-lock-delimiter-face) :language 'json :feature 'number '((number) @font-lock-number-face) :language 'json :feature 'string '((string) @font-lock-string-face) :language 'json :feature 'escape-sequence :override t '((escape_sequence) @font-lock-escape-face) :language 'json :feature 'error :override t '((ERROR) @font-lock-warning-face)) "Font-lock settings for JSON.") (defun json-ts-mode--imenu-1 (node) "Helper for `json-ts-mode--imenu'. Find string representation for NODE and set marker, then recurse the subtrees." (let* ((ts-node (car node)) (subtrees (mapcan #'json-ts-mode--imenu-1 (cdr node))) (name (when ts-node (treesit-node-text (treesit-node-child-by-field-name ts-node "key") t))) (marker (when ts-node (set-marker (make-marker) (treesit-node-start ts-node))))) (cond ((null ts-node) subtrees) (subtrees `((,name ,(cons name marker) ,@subtrees))) (t `((,name . ,marker)))))) (defun json-ts-mode--imenu () "Return Imenu alist for the current buffer." (let* ((node (treesit-buffer-root-node)) (tree (treesit-induce-sparse-tree node "pair"))) (json-ts-mode--imenu-1 tree))) ;;;###autoload (define-derived-mode json-ts-mode prog-mode "JSON" "Major mode for editing JSON, powered by tree-sitter." :group 'json :syntax-table json-ts-mode--syntax-table (unless (treesit-ready-p 'json) (error "Tree-sitter for JSON isn't available")) (treesit-parser-create 'json) ;; Comments. (setq-local comment-start "// ") (setq-local comment-start-skip "\\(?://+\\|/\\*+\\)\\s *") (setq-local comment-end "") ;; Electric (setq-local electric-indent-chars (append "{}():;," electric-indent-chars)) ;; Indent. (setq-local treesit-simple-indent-rules json-ts--indent-rules) ;; Navigation. (setq-local treesit-defun-type-regexp (rx (or "pair" "object"))) ;; Font-lock. (setq-local treesit-font-lock-settings json-ts-mode--font-lock-settings) (setq-local treesit-font-lock-feature-list '((constant number string) (escape-sequence) (bracket delimiter error))) ;; Imenu. (setq-local imenu-create-index-function #'json-ts-mode--imenu) (setq-local which-func-functions nil) ;; Piggyback on imenu (treesit-major-mode-setup)) (provide 'json-ts-mode) ;;; json-ts-mode.el ends here