;;; html-ts-mode.el --- tree-sitter support for HTML -*- lexical-binding: t; -*-
;; Copyright (C) 2023 Free Software Foundation, Inc.
;; Author : Theodor Thornhill
;; Maintainer : Theodor Thornhill
;; Created : January 2023
;; Keywords : html languages tree-sitter
;; This file is part of GNU Emacs.
;; GNU Emacs 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.
;; GNU Emacs 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 GNU Emacs. If not, see .
;;; Commentary:
;;
;;; Code:
(require 'treesit)
(require 'sgml-mode)
(declare-function treesit-parser-create "treesit.c")
(declare-function treesit-node-type "treesit.c")
(defcustom html-ts-mode-indent-offset 2
"Number of spaces for each indentation step in `html-ts-mode'."
:version "29.1"
:type 'integer
:safe 'integerp
:group 'html)
(defvar html-ts-mode--indent-rules
`((html
((parent-is "fragment") parent-bol 0)
((node-is "/>") parent-bol 0)
((node-is ">") parent-bol 0)
((node-is "end_tag") parent-bol 0)
((parent-is "comment") prev-adaptive-prefix 0)
((parent-is "element") parent-bol html-ts-mode-indent-offset)
((parent-is "script_element") parent-bol html-ts-mode-indent-offset)
((parent-is "style_element") parent-bol html-ts-mode-indent-offset)
((parent-is "start_tag") parent-bol html-ts-mode-indent-offset)
((parent-is "self_closing_tag") parent-bol html-ts-mode-indent-offset)))
"Tree-sitter indent rules.")
(defvar html-ts-mode--font-lock-settings
(treesit-font-lock-rules
:language 'html
:override t
:feature 'comment
`((comment) @font-lock-comment-face)
:language 'html
:override t
:feature 'keyword
`("doctype" @font-lock-keyword-face)
:language 'html
:override t
:feature 'definition
`((tag_name) @font-lock-function-name-face)
:language 'html
:override t
:feature 'string
`((quoted_attribute_value) @font-lock-string-face)
:language 'html
:override t
:feature 'property
`((attribute_name) @font-lock-variable-name-face))
"Tree-sitter font-lock settings for `html-ts-mode'.")
(defun html-ts-mode--defun-name (node)
"Return the defun name of NODE.
Return nil if there is no name or if NODE is not a defun node."
(when (equal (treesit-node-type node) "tag_name")
(treesit-node-text node t)))
;;;###autoload
(define-derived-mode html-ts-mode html-mode "HTML"
"Major mode for editing Html, powered by tree-sitter."
:group 'html
(unless (treesit-ready-p 'html)
(error "Tree-sitter for HTML isn't available"))
(treesit-parser-create 'html)
;; Comments.
(setq-local treesit-text-type-regexp
(regexp-opt '("comment" "text")))
;; Indent.
(setq-local treesit-simple-indent-rules html-ts-mode--indent-rules)
;; Navigation.
(setq-local treesit-defun-type-regexp "element")
(setq-local treesit-defun-name-function #'html-ts-mode--defun-name)
(setq-local treesit-sentence-type-regexp "tag")
(setq-local treesit-sexp-type-regexp
(regexp-opt '("element"
"text"
"attribute"
"value")))
;; Font-lock.
(setq-local treesit-font-lock-settings html-ts-mode--font-lock-settings)
(setq-local treesit-font-lock-feature-list
'((comment keyword definition)
(property string)
() ()))
;; Imenu.
(setq-local treesit-simple-imenu-settings
'(("Element" "\\`tag_name\\'" nil nil)))
(treesit-major-mode-setup))
(if (treesit-ready-p 'html)
(add-to-list 'auto-mode-alist '("\\.html\\'" . html-ts-mode)))
(provide 'html-ts-mode)
;;; html-ts-mode.el ends here