bug#74610: 31.0.50; Submitting mhtml-ts-mode, treesitter alternative to mhtml-mode

bug#74610: 31.0.50; Submitting mhtml-ts-mode, treesitter alternative to mhtml-mode

[Vincenzo Pupillo]

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Ciao,
following the discussion 
https://lists.gnu.org/archive/html/emacs-devel/2024-11/msg00079.html I would 
like to ask if it would be possible to add to emacs this new mode for editing 
html files alternative to mhtml-mode.

Thank you.

Vincenzo.

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From 8a1c792aaddf4daef2808f5a74212a2fb8b0a01e Mon Sep 17 00:00:00 2001
From: Vincenzo Pupillo <v.pupillo@gmail.com>
Date: Fri, 29 Nov 2024 22:48:45 +0100
Subject: [PATCH] Add mhtml-ts-mode.

New major-mode alternative to mhtml-mode, based on treesitter, for
editing files containing html, javascript and css.

* etc/NEWS: Mention the new mode.
* lisp/textmodes/mhtml-ts-mode.el: New file.
---
 etc/NEWS                        |   8 +
 lisp/textmodes/mhtml-ts-mode.el | 462 ++++++++++++++++++++++++++++++++
 2 files changed, 470 insertions(+)
 create mode 100644 lisp/textmodes/mhtml-ts-mode.el

diff --git a/etc/NEWS b/etc/NEWS
index 4d2a2c893d0..8f9a04dcf01 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -797,6 +797,14 @@ destination window is chosen using 'display-buffer-alist'.  Example:
 \f
 * New Modes and Packages in Emacs 31.1
 
+** New major modes based on the tree-sitter library
+
++++
+*** New major mode 'mhtml-ts-mode'.
+An optional major mode based on the tree-sitter library for editing html
+files. This mode handles indentation, fontification, and commenting for
+embedded JavaScript and CSS.
+
 \f
 * Incompatible Lisp Changes in Emacs 31.1
 
diff --git a/lisp/textmodes/mhtml-ts-mode.el b/lisp/textmodes/mhtml-ts-mode.el
new file mode 100644
index 00000000000..b6b220663e3
--- /dev/null
+++ b/lisp/textmodes/mhtml-ts-mode.el
@@ -0,0 +1,462 @@
+;;; mhtml-ts-mode.el --- Major mode for HTML using tree-sitter -*- lexical-binding: t; -*-
+
+;; Copyright (C) 2024 Free Software Foundation, Inc.
+
+;; Author: Vincenzo Pupillo <v.pupillo@gmail.com>
+;; Maintainer: Vincenzo Pupillo <v.pupillo@gmail.com>
+;; Created: Nov 2024
+;; Keywords: HTML language 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 <https://www.gnu.org/licenses/>.
+
+;;; Commentary:
+;;
+;; This package provides `mhtml-ts-mode' which is a major mode
+;; for editing HTML files with embedded JavaScript and CSS.
+;; Tree Sitter is used to parse each of these languages.
+;;
+;; Please note that this package requires `html-ts-mode', which
+;; registers itself as the major mode for editing HTML.
+;;
+;; This package is compatible and has been tested with the following
+;; tree-sitter grammars:
+;; * https://github.com/tree-sitter/tree-sitter-html
+;; * https://github.com/tree-sitter/tree-sitter-javascript
+;; * https://github.com/tree-sitter/tree-sitter-jsdoc
+;; * https://github.com/tree-sitter/tree-sitter-css
+;;
+;; Features
+;;
+;; * Indent
+;; * IMenu
+;; * Navigation
+;; * Which-function
+;; * Tree-sitter parser installation helper
+
+;;; Code:
+
+(require 'treesit)
+(require 'html-ts-mode)
+(require 'css-mode) ;; for embed css into html
+(require 'js) ;; for embed javascript into html
+
+(eval-when-compile
+  (require 'rx))
+
+;; Declare all native functions used by the major mode.
+;; This tells the byte-compiler where the functions are defined.
+(declare-function treesit-node-end "treesit.c")
+(declare-function treesit-node-parent "treesit.c")
+(declare-function treesit-node-start "treesit.c")
+(declare-function treesit-node-type "treesit.c")
+(declare-function treesit-parser-create "treesit.c")
+
+;; In a multi-language major mode can be useful to have an "installer" to
+;; simplify the installation of the grammars supported by the major-mode.
+(defvar mhtml-ts-mode--language-source-alist
+  '((html . ("https://github.com/tree-sitter/tree-sitter-html"  "v0.23.0"))
+    (javascript . ("https://github.com/tree-sitter/tree-sitter-javascript" "v0.23.0"))
+    (jsdoc . ("https://github.com/tree-sitter/tree-sitter-jsdoc" "v0.23.0"))
+    (css . ("https://github.com/tree-sitter/tree-sitter-css" "v0.23.0")))
+  "Treesitter language parsers required by `mhtml-ts-mode'.
+You can customize this variable if you want to stick to a specific
+commit and/or use different parsers.")
+
+(defun mhtml-ts-mode-install-parsers ()
+  "Install all the required treesitter parsers.
+`mhtml-ts-mode--language-source-alist' defines which parsers to install."
+  (interactive)
+  (let ((treesit-language-source-alist mhtml-ts-mode--language-source-alist))
+    (dolist (item mhtml-ts-mode--language-source-alist)
+      (treesit-install-language-grammar (car item)))))
+
+;;; Custom variables
+
+(defgroup mhtml-ts-mode nil
+  "Major mode for editing HTML files, based on `html-ts-mode'.
+Works with JS and CSS and for that use `js-ts-mode' and `css-ts-mode'."
+  :prefix "html-ts-mode-"
+  :group 'languages)
+
+(defcustom mhtml-ts-mode-js-css-indent-offset 2
+  "JavaScript and CSS indent spaces related to the <script> and <style> HTML tags.
+By default should have same value as `html-ts-mode-indent-offset'."
+  :tag "HTML javascript or css indent offset"
+  :version "31.1"
+  :type 'integer
+  :safe 'integerp)
+
+(defvar mhtml-ts-mode--js-css-indent-offset
+  mhtml-ts-mode-js-css-indent-offset
+  "Internal copy of `mhtml-ts-mode-js-css-indent-offset'.
+The value changes, by `mhtml-ts-mode--tag-relative-indent-offset' according to
+the value of `mhtml-ts-mode-tag-relative-indent'.")
+
+(defun mhtml-ts-mode--tag-relative-indent-offset (sym val)
+  "Custom setter for `mhtml-ts-mode-tag-relative-indent'.
+
+Apart from setting the default value of SYM to VAL, also change the
+value of SYM in `mhtml-ts-mode' buffers to VAL.  SYM should be
+`mhtml-ts-mode-tag-relative-indent', and VAL should be t, nil or
+`ignore'.  When sym is `mhtml-ts-mode-tag-relative-indent' set the
+value of `mhtml-ts-mode--js-css-indent-offset' to 0 if VAL is t,
+otherwise to `mhtml-ts-mode-js-css-indent-offset'."
+  (set-default sym val)
+  (when (eq sym 'mhtml-ts-mode-tag-relative-indent)
+    (setq-local
+     mhtml-ts-mode--js-css-indent-offset
+     (if (eq val t)
+         mhtml-ts-mode-js-css-indent-offset
+       0))))
+
+(defcustom mhtml-ts-mode-tag-relative-indent t
+  "How <script> and <style> bodies are indented relative to the tag.
+
+When t, indentation looks like:
+
+  <script>
+    code();
+  </script>
+
+When nil, indentation of the script body starts just below the
+tag, like:
+
+  <script>
+  code();
+  </script>
+
+When `ignore', the script body starts in the first column, like:
+
+  <script>
+code();
+  </script>"
+  :type '(choice (const nil) (const t) (const ignore))
+  :safe 'symbolp
+  :set #'mhtml-ts-mode--tag-relative-indent-offset
+  :version "31.1")
+
+(defcustom mhtml-ts-mode-css-fontify-colors t
+  "Whether CSS colors should be fontified using the color as the background.
+If non-nil, text representing a CSS color will be fontified
+such that its background is the color itself.
+Works like `css--fontify-region'."
+  :tag "HTML colors the CSS properties values."
+  :version "31.1"
+  :type 'boolean
+  :safe 'booleanp)
+
+;; To enable some basic treesiter functionality, you should define
+;; a function that recognizes which grammar is used at-point.
+;; This function should be assigned to `treesit-language-at-point-function'
+(defun mhtml-ts-mode--language-at-point (point)
+  "Return the language at POINT assuming the point is within a HTML buffer."
+  (let* ((node (treesit-node-at point 'html))
+         (parent (treesit-node-parent node))
+         (node-query (format "(%s (%s))"
+                             (treesit-node-type parent)
+                             (treesit-node-type node))))
+    (cond
+     ((string-equal "(script_element (raw_text))" node-query) 'javascript)
+     ((string-equal "(style_element (raw_text))" node-query) 'css)
+     (t 'html))))
+
+;; Sometimes you need to override some property attached to a node.
+;; The signature of the function should be conforming to signature
+;; QUERY-SPEC required by `treesit-font-lock-rules'.
+(defun mhtml-ts-mode--colorize-css-value (node override start end &rest _)
+  "Colorize CSS property value like `css--fontify-region'.
+For NODE, OVERRIDE, START, and END, see `treesit-font-lock-rules'."
+  (if (and mhtml-ts-mode-css-fontify-colors
+           (string-equal "plain_value" (treesit-node-type node)))
+      (let ((color (css--compute-color start (treesit-node-text node t))))
+        (when color
+          (with-silent-modifications
+            (add-text-properties
+             (treesit-node-start node) (treesit-node-end node)
+             (list 'face (list :background color
+                               :foreground (readable-foreground-color
+                                            color)
+                               :box '(:line-width -1)))))))
+    (treesit-fontify-with-override
+     (treesit-node-start node) (treesit-node-end node)
+     'font-lock-variable-name-face
+     override start end)))
+
+;; Embedded languages ​​should be indented according to the language
+;; that embeds them.
+;; This function signature complies with `treesit-simple-indent-rules'
+;; ANCHOR.
+(defun mhtml-ts-mode--js-css-tag-bol (_node _parent &rest _)
+  "Find the first non-space characters of html tags <script> or <style>.
+Return `line-beginning-position' when `treesit-node-at' is html, or
+`mhtml-ts-mode-tag-relative-indent' is equal to ignore.
+NODE and PARENT are ignored."
+  (if (or (eq (treesit-language-at (point)) 'html)
+          (eq mhtml-ts-mode-tag-relative-indent 'ignore))
+      (line-beginning-position)
+    ;; Ok, we are in js or css block.
+    (save-excursion
+      (re-search-backward "<script.*>\\|<style.*>" nil t))))
+
+;; Treesit supports 4 level of decoration, `treesit-font-lock-level'
+;; define which level use.  Major-modes categorize their fontification
+;; features, these categories are defined by `treesit-font-lock-rules' of
+;; each major-mode using :feature keyword.
+;; In a multiple language major-mode it's a good idea to provvide, for each
+;; level, the union of the :feature of the same level.
+(defvar mhtml-ts-mode--feature-list
+  '(;; level 1
+    (;; common
+     comment definition
+     ;; JS specific
+     document
+     ;; CSS specific
+     query selector)
+    ;; level 2
+    (keyword name property string type)
+    ;; level 3
+    (;; common
+     attribute assignment constant escape-sequence
+     base-clause literal variable-name variable
+     ;; Javascript specific
+     jsx number pattern string-interpolation)
+    ;; level 4
+    (bracket delimiter error operator function)))
+
+;; In order to support wich-fuction-mode we should define
+;; a function that return the defun name.
+;; In a multilingual treesit mode, this can be implemented simply by
+;; calling language-specific functions.
+(defun mhtml-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."
+  ;; (message "node type ""%s""" (treesit-node-type node))
+  (let ((lang (mhtml-ts-mode--language-at-point (point))))
+    (cond
+     ((eq lang 'html) (html-ts-mode--defun-name node))
+     ((eq lang 'javascript) (js--treesit-defun-name node))
+     ((eq lang 'css) (css--treesit-defun-name node)))))
+
+(define-derived-mode mhtml-ts-mode html-mode
+  '("HTML+" (:eval (let ((lang (mhtml-ts-mode--language-at-point (point))))
+                     (cond ((eq lang 'html) "")
+                           ((eq lang 'javascript) "JS")
+                           ((eq lang 'css) "CSS")))))
+  "Major mode for editing HTML with embedded JavaScript and CSS.
+Powered by tree-sitter."
+  (if (not (and
+            (treesit-ready-p 'html)
+            (treesit-ready-p 'javascript)
+            (treesit-ready-p 'css)))
+      (error "Tree-sitter parsers for HTML isn't
+    available.  You can install the parsers with M-x
+    `mhtml-ts-mode-install-parsers'")
+
+    ;; When an language is embedded, you should initialize some variable
+    ;; just like it's done in the original mode.
+
+    ;; Comment.
+    ;; indenting settings for js-ts-mode.
+    (c-ts-common-comment-setup)
+    (setq-local comment-multi-line t)
+
+    ;; Font-lock.
+
+    ;; There are two kind of treesitter parser:
+    ;; 1. global parser
+    ;; 2. local parser
+    ;; The global parser considers each piece of text,
+    ;; in a multilingual buffer, as if it were a single buffer in its
+    ;; own language. Local parsers, on the other hand, consider each
+    ;; piece of text, in a multilingual buffer, as if they were
+    ;; separate buffers.
+    ;; In a multilingual buffer you should create only global ones.
+    ;; Local ones are created automatically.
+    ;; Warning: do not create a local parser! It may cause side
+    ;; effects that are difficult to handle.
+
+    ;; There are two types of treesitter parsers:
+    ;; 1. global parsers
+    ;; 2. local parsers
+    ;; A global parser treats each piece of text,
+    ;; in a multilingual buffer, as if it were a single buffer in its
+    ;; language. Local parser, on the other hand, treat each
+    ;; piece of text, in a multilingual buffer, as if they were separate buffers.
+    ;; In a multilingual buffer you should only create global ones.
+    ;; The local ones are created automatically.
+    ;; Warning: do not create a local parser! It may cause side effects that are difficult to handle.
+
+    ;; Create the parsers, only the global one.
+    ;; jsdoc is a local parser, don't create a parser for it.
+    (treesit-parser-create 'css)
+    (treesit-parser-create 'javascript)
+
+    ;; jsdoc is not mandatory for js-ts-mode, so we respect this by
+    ;; adding jsdoc range rules only when jsdoc is available.
+    (if (treesit-ready-p 'jsdoc t)
+        (setq-local treesit-range-settings
+                    (treesit-range-rules
+                     :embed 'javascript
+                     :host 'html
+                     :offset '(1 . -1)
+                     '((script_element
+                        (start_tag (tag_name))
+                        (raw_text) @cap))
+
+                     :embed 'jsdoc
+                     :host 'javascript
+                     :local t
+                     `(((comment) @cap
+                        (:match ,js--treesit-jsdoc-beginning-regexp @cap)))
+
+                     :embed 'css
+                     :host 'html
+                     :offset '(1 . -1)
+                     '((style_element
+                        (start_tag (tag_name))
+                        (raw_text) @cap))))
+      (setq-local treesit-range-settings
+                  (treesit-range-rules
+                   :embed 'javascript
+                   :host 'html
+                   :offset '(1 . -1)
+                   '((script_element
+                      (start_tag (tag_name))
+                      (raw_text) @cap))
+
+                   :embed 'css
+                   :host 'html
+                   :offset '(1 . -1)
+                   '((style_element
+                      (start_tag (tag_name))
+                      (raw_text) @cap)))))
+
+    ;; Many treesit fuctions need to know the language at-point.
+    ;; So you should define such a function.
+    (setq-local treesit-language-at-point-function #'mhtml-ts-mode--language-at-point)
+
+    ;; Indent.
+
+    ;; Since mhtl-ts-mode inherits indentation rules from html-ts-mode, js
+    ;; and css, if you want to change the offset you have to act on the
+    ;; *-offset variables defined for those languages.
+
+    ;; JavaScript and CSS must be indented relative to their code block.
+    ;; This is done by inserting a special rule before the normal
+    ;; indentation rules of these languages.
+    ;; The value of mhtml-ts-mode--js-css-indent-offset changes based on
+    ;; mhtml-ts-mode-tag-relative-indent and can be used to indent
+    ;; JavaScript and CSS code relative to the HTML that contains them,
+    ;; just like in mhtml-mode.
+    (setq-local treesit-simple-indent-rules
+                (append html-ts-mode--indent-rules
+                        ;; Extended rules for js and css, to
+                        ;; indent appropriately when injected
+                        ;; into html
+                        `((javascript ((parent-is "program")
+                                       mhtml-ts-mode--js-css-tag-bol
+                                       mhtml-ts-mode--js-css-indent-offset)
+                                      ,@(cdr (car js--treesit-indent-rules))))
+                        `((css ((parent-is "stylesheet")
+                                mhtml-ts-mode--js-css-tag-bol
+                                mhtml-ts-mode--js-css-indent-offset)
+                               ,@(cdr (car css--treesit-indent-rules))))))
+    ;; Navigation.
+
+    ;; This regular expression tells treesit how to match the node type
+    ;; of defun nodes.
+    ;; Used by `treesit-beginning-of-defun' and friends for
+    ;; navigations.
+    (setq-local treesit-defun-type-regexp
+                (rx (or
+                     ;; Javascript
+                     "class_declaration"
+                     "method_definition"
+                     "function_declaration"
+                     "lexical_declaration"
+                     ;; HTML
+                     "element"
+                     ;; CSS
+                     "rule_set")))
+
+    ;; This is for finding defun name, it's used by IMenu as default
+    ;; function no specific functions are defined.
+    (setq-local treesit-defun-name-function #'mhtml-ts-mode--defun-name)
+
+    ;; Define what are 'thing' for treesit.
+    ;; 'Thing' is a symbol representing the thing, like `defun', `sexp', or
+    ;; `sentence'.
+    (setq-local treesit-thing-settings
+                `((html
+                   (sexp ,(regexp-opt '("element"
+                                        "text"
+                                        "attribute"
+                                        "value")))
+                   (sentence "tag")
+                   (text ,(regexp-opt '("comment" "text"))))
+                  (javascript
+                   (sexp ,(js--regexp-opt-symbol js--treesit-sexp-nodes))
+                   (sentence ,(js--regexp-opt-symbol js--treesit-sentence-nodes))
+                   (text ,(js--regexp-opt-symbol '("comment"
+                                                   "string_fragment"))))))
+
+    ;; Font-lock.
+
+    ;; In a multi-language scenario, font lock settings are usually a
+    ;; concatenation of language rules. As you can see, it is possible
+    ;; to extend/modify the default rule or use a different set of
+    ;; rules. See `php-ts-mode--custom-html-font-lock-settings' for more
+    ;; advanced usage.
+    (setq-local treesit-font-lock-settings
+                (append html-ts-mode--font-lock-settings
+                        js--treesit-font-lock-settings
+                        (append
+                         ;; Rule for coloring CSS property values.
+                         ;; Placed before `css--treesit-settings'
+                         ;; to win against the same rule contained therein.
+                         (treesit-font-lock-rules
+                          :language 'css
+                          :override t
+                          :feature 'variable
+                          '((plain_value) @mhtml-ts-mode--colorize-css-value))
+                         css--treesit-settings)))
+
+    ;; Tells treesit the list of features to fontify.
+    (setq-local treesit-font-lock-feature-list mhtml-ts-mode--feature-list)
+
+    ;; Imenu
+
+    ;; Setup Imenu: if no function is specified, try to find an object
+    ;; using `treesit-defun-name-function'.
+    ;; TODO: we need to see if it is possible to extend Imenu to
+    ;; embedded languages ​​as well.
+    (setq-local treesit-simple-imenu-settings
+                `(("Element" "\\`tag_name\\'" nil nil)))
+
+    ;; This should be the last thing to do.
+    ;; Treesit tries to find out what the primary language is, but it is better
+    ;; to say it explicitly.
+    (setq-local treesit-primary-parser (treesit-parser-create 'html))
+
+    (treesit-font-lock-recompute-features)
+    (treesit-major-mode-setup)))
+
+(when (and (treesit-ready-p 'html) (treesit-ready-p 'javascript) (treesit-ready-p 'css))
+  (add-to-list
+   'auto-mode-alist '("\\.[sx]?html?\\(\\.[a-zA-Z_]+\\)?\\'" . mhtml-ts-mode)))
+
+(provide 'mhtml-ts-mode)
+;;; mhtml-ts-mode.el ends here
-- 
2.47.1

bug#74610: 31.0.50; Submitting mhtml-ts-mode, treesitter alternative to mhtml-mode

[Yuan Fu]

> On Nov 29, 2024, at 1:57 PM, Vincenzo Pupillo <v.pupillo@gmail.com> wrote:
> 
> Ciao,
> following the discussion 
> https://lists.gnu.org/archive/html/emacs-devel/2024-11/msg00079.html I would 
> like to ask if it would be possible to add to emacs this new mode for editing 
> html files alternative to mhtml-mode.
> 
> Thank you.
> 
> Vincenzo.<0001-Add-mhtml-ts-mode.patch>

Thank you so much! This will be very helpful for others. Here’re some comments.

Yuan

From 8a1c792aaddf4daef2808f5a74212a2fb8b0a01e Mon Sep 17 00:00:00 2001
From: Vincenzo Pupillo <v.pupillo@gmail.com>
Date: Fri, 29 Nov 2024 22:48:45 +0100
Subject: [PATCH] Add mhtml-ts-mode.

New major-mode alternative to mhtml-mode, based on treesitter, for
editing files containing html, javascript and css.

* etc/NEWS: Mention the new mode.
* lisp/textmodes/mhtml-ts-mode.el: New file.
---
 etc/NEWS                        |   8 +
 lisp/textmodes/mhtml-ts-mode.el | 462 ++++++++++++++++++++++++++++++++
 2 files changed, 470 insertions(+)
 create mode 100644 lisp/textmodes/mhtml-ts-mode.el

diff --git a/etc/NEWS b/etc/NEWS
index 4d2a2c893d0..8f9a04dcf01 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -797,6 +797,14 @@ destination window is chosen using 'display-buffer-alist'.  Example:
 \f
 * New Modes and Packages in Emacs 31.1
 
+** New major modes based on the tree-sitter library
+
++++
+*** New major mode 'mhtml-ts-mode'.
+An optional major mode based on the tree-sitter library for editing html
+files. This mode handles indentation, fontification, and commenting for
+embedded JavaScript and CSS.
+
 \f
 * Incompatible Lisp Changes in Emacs 31.1
 
diff --git a/lisp/textmodes/mhtml-ts-mode.el b/lisp/textmodes/mhtml-ts-mode.el
new file mode 100644
index 00000000000..b6b220663e3
--- /dev/null
+++ b/lisp/textmodes/mhtml-ts-mode.el
@@ -0,0 +1,100 @@
+;;; mhtml-ts-mode.el --- Major mode for HTML using tree-sitter -*- lexical-binding: t; -*-
+
+;; Copyright (C) 2024 Free Software Foundation, Inc.
+
+;; Author: Vincenzo Pupillo <v.pupillo@gmail.com>
+;; Maintainer: Vincenzo Pupillo <v.pupillo@gmail.com>
+;; Created: Nov 2024
+;; Keywords: HTML language 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 <https://www.gnu.org/licenses/>.
+
+;;; Commentary:
+;;
+;; This package provides `mhtml-ts-mode' which is a major mode
+;; for editing HTML files with embedded JavaScript and CSS.
+;; Tree Sitter is used to parse each of these languages.
+;;
+;; Please note that this package requires `html-ts-mode', which
+;; registers itself as the major mode for editing HTML.
+;;
+;; This package is compatible and has been tested with the following
+;; tree-sitter grammars:
+;; * https://github.com/tree-sitter/tree-sitter-html
+;; * https://github.com/tree-sitter/tree-sitter-javascript
+;; * https://github.com/tree-sitter/tree-sitter-jsdoc
+;; * https://github.com/tree-sitter/tree-sitter-css
+;;
+;; Features
+;;
+;; * Indent
+;; * IMenu
+;; * Navigation
+;; * Which-function
+;; * Tree-sitter parser installation helper
+
+;;; Code:
+
+(require 'treesit)
+(require 'html-ts-mode)
+(require 'css-mode) ;; for embed css into html
+(require 'js) ;; for embed javascript into html
+
+(eval-when-compile
+  (require 'rx))
+
+;; Declare all native functions used by the major mode.
+;; This tells the byte-compiler where the functions are defined.
+(declare-function treesit-node-end "treesit.c")
+(declare-function treesit-node-parent "treesit.c")
+(declare-function treesit-node-start "treesit.c")
+(declare-function treesit-node-type "treesit.c")
+(declare-function treesit-parser-create "treesit.c")
+
+;; In a multi-language major mode can be useful to have an "installer" to
+;; simplify the installation of the grammars supported by the major-mode.
+(defvar mhtml-ts-mode--language-source-alist
+  '((html . ("https://github.com/tree-sitter/tree-sitter-html"  "v0.23.0"))
+    (javascript . ("https://github.com/tree-sitter/tree-sitter-javascript" "v0.23.0"))
+    (jsdoc . ("https://github.com/tree-sitter/tree-sitter-jsdoc" "v0.23.0"))
+    (css . ("https://github.com/tree-sitter/tree-sitter-css" "v0.23.0")))
+  "Treesitter language parsers required by `mhtml-ts-mode'.
+You can customize this variable if you want to stick to a specific
+commit and/or use different parsers.")
+
+(defun mhtml-ts-mode-install-parsers ()
+  "Install all the required treesitter parsers.
+`mhtml-ts-mode--language-source-alist' defines which parsers to install."
+  (interactive)
+  (let ((treesit-language-source-alist mhtml-ts-mode--language-source-alist))
+    (dolist (item mhtml-ts-mode--language-source-alist)
+      (treesit-install-language-grammar (car item)))))
+
+;;; Custom variables
+
+(defgroup mhtml-ts-mode nil
+  "Major mode for editing HTML files, based on `html-ts-mode'.
+Works with JS and CSS and for that use `js-ts-mode' and `css-ts-mode'."
+  :prefix "html-ts-mode-"
+  :group 'languages)
+
+(defcustom mhtml-ts-mode-js-css-indent-offset 2
+  "JavaScript and CSS indent spaces related to the <script> and <style> HTML tags.
+By default should have same value as `html-ts-mode-indent-offset'."
+  :tag "HTML javascript or css indent offset"
+  :version "31.1"
+  :type 'integer
+  :safe 'integerp)

It's not uncommon to see different indent offset for CSS and
Javascript, so it's a good idea to have separate control for them.

+
+(defvar mhtml-ts-mode--js-css-indent-offset
+  mhtml-ts-mode-js-css-indent-offset
+  "Internal copy of `mhtml-ts-mode-js-css-indent-offset'.
+The value changes, by `mhtml-ts-mode--tag-relative-indent-offset' according to
+the value of `mhtml-ts-mode-tag-relative-indent'.")
+
+(defun mhtml-ts-mode--tag-relative-indent-offset (sym val)
+  "Custom setter for `mhtml-ts-mode-tag-relative-indent'.
+
+Apart from setting the default value of SYM to VAL, also change the
+value of SYM in `mhtml-ts-mode' buffers to VAL.  SYM should be
+`mhtml-ts-mode-tag-relative-indent', and VAL should be t, nil or
+`ignore'.  When sym is `mhtml-ts-mode-tag-relative-indent' set the
+value of `mhtml-ts-mode--js-css-indent-offset' to 0 if VAL is t,
+otherwise to `mhtml-ts-mode-js-css-indent-offset'."
+  (set-default sym val)
+  (when (eq sym 'mhtml-ts-mode-tag-relative-indent)
+    (setq-local
+     mhtml-ts-mode--js-css-indent-offset
+     (if (eq val t)
+         mhtml-ts-mode-js-css-indent-offset
+       0))))
+
+(defcustom mhtml-ts-mode-tag-relative-indent t
+  "How <script> and <style> bodies are indented relative to the tag.
+
+When t, indentation looks like:
+
+  <script>
+    code();
+  </script>
+
+When nil, indentation of the script body starts just below the
+tag, like:
+
+  <script>
+  code();
+  </script>
+
+When `ignore', the script body starts in the first column, like:
+
+  <script>
+code();
+  </script>"
+  :type '(choice (const nil) (const t) (const ignore))
+  :safe 'symbolp
+  :set #'mhtml-ts-mode--tag-relative-indent-offset
+  :version "31.1")
+
+(defcustom mhtml-ts-mode-css-fontify-colors t
+  "Whether CSS colors should be fontified using the color as the background.
+If non-nil, text representing a CSS color will be fontified
+such that its background is the color itself.
+Works like `css--fontify-region'."
+  :tag "HTML colors the CSS properties values."
+  :version "31.1"
+  :type 'boolean
+  :safe 'booleanp)
+
+;; To enable some basic treesiter functionality, you should define
+;; a function that recognizes which grammar is used at-point.
+;; This function should be assigned to `treesit-language-at-point-function'
+(defun mhtml-ts-mode--language-at-point (point)
+  "Return the language at POINT assuming the point is within a HTML buffer."
+  (let* ((node (treesit-node-at point 'html))
+         (parent (treesit-node-parent node))
+         (node-query (format "(%s (%s))"
+                             (treesit-node-type parent)
+                             (treesit-node-type node))))
+    (cond
+     ((string-equal "(script_element (raw_text))" node-query) 'javascript)
+     ((string-equal "(style_element (raw_text))" node-query) 'css)
+     (t 'html))))
+
+;; Sometimes you need to override some property attached to a node.
+;; The signature of the function should be conforming to signature
+;; QUERY-SPEC required by `treesit-font-lock-rules'.

"property attached to a node" is vague. I would just say

;; Custom font-lock function that's used to apply color to css color
;; values. This function is used below where we define font-lock rules.

+(defun mhtml-ts-mode--colorize-css-value (node override start end &rest _)
+  "Colorize CSS property value like `css--fontify-region'.
+For NODE, OVERRIDE, START, and END, see `treesit-font-lock-rules'."
+  (if (and mhtml-ts-mode-css-fontify-colors
+           (string-equal "plain_value" (treesit-node-type node)))
+      (let ((color (css--compute-color start (treesit-node-text node t))))
+        (when color
+          (with-silent-modifications
+            (add-text-properties
+             (treesit-node-start node) (treesit-node-end node)
+             (list 'face (list :background color
+                               :foreground (readable-foreground-color
+                                            color)
+                               :box '(:line-width -1)))))))
+    (treesit-fontify-with-override
+     (treesit-node-start node) (treesit-node-end node)
+     'font-lock-variable-name-face
+     override start end)))
+
+;; Embedded languages ​​should be indented according to the language
+;; that embeds them.
+;; This function signature complies with `treesit-simple-indent-rules'
+;; ANCHOR.
+(defun mhtml-ts-mode--js-css-tag-bol (_node _parent &rest _)
+  "Find the first non-space characters of html tags <script> or <style>.
+Return `line-beginning-position' when `treesit-node-at' is html, or
+`mhtml-ts-mode-tag-relative-indent' is equal to ignore.
+NODE and PARENT are ignored."
+  (if (or (eq (treesit-language-at (point)) 'html)
+          (eq mhtml-ts-mode-tag-relative-indent 'ignore))
+      (line-beginning-position)
+    ;; Ok, we are in js or css block.
+    (save-excursion
+      (re-search-backward "<script.*>\\|<style.*>" nil t))))
+
+;; Treesit supports 4 level of decoration, `treesit-font-lock-level'
+;; define which level use.  Major-modes categorize their fontification
+;; features, these categories are defined by `treesit-font-lock-rules' of
+;; each major-mode using :feature keyword.
+;; In a multiple language major-mode it's a good idea to provvide, for each
+;; level, the union of the :feature of the same level.

"which level to use", "Major modes", and "provide"

+(defvar mhtml-ts-mode--feature-list
+  '(;; level 1
+    (;; common
+     comment definition
+     ;; JS specific
+     document
+     ;; CSS specific
+     query selector)
+    ;; level 2
+    (keyword name property string type)
+    ;; level 3
+    (;; common
+     attribute assignment constant escape-sequence
+     base-clause literal variable-name variable
+     ;; Javascript specific
+     jsx number pattern string-interpolation)
+    ;; level 4
+    (bracket delimiter error operator function)))
+
+;; In order to support wich-fuction-mode we should define

"which-function-mode"

+;; a function that return the defun name.
+;; In a multilingual treesit mode, this can be implemented simply by
+;; calling language-specific functions.
+(defun mhtml-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."
+  ;; (message "node type ""%s""" (treesit-node-type node))
+  (let ((lang (mhtml-ts-mode--language-at-point (point))))
+    (cond
+     ((eq lang 'html) (html-ts-mode--defun-name node))
+     ((eq lang 'javascript) (js--treesit-defun-name node))
+     ((eq lang 'css) (css--treesit-defun-name node)))))
+
+(define-derived-mode mhtml-ts-mode html-mode
+  '("HTML+" (:eval (let ((lang (mhtml-ts-mode--language-at-point (point))))
+                     (cond ((eq lang 'html) "")
+                           ((eq lang 'javascript) "JS")
+                           ((eq lang 'css) "CSS")))))
+  "Major mode for editing HTML with embedded JavaScript and CSS.
+Powered by tree-sitter."
+  (if (not (and
+            (treesit-ready-p 'html)
+            (treesit-ready-p 'javascript)
+            (treesit-ready-p 'css)))
+      (error "Tree-sitter parsers for HTML isn't
+    available.  You can install the parsers with M-x
+    `mhtml-ts-mode-install-parsers'")
+
+    ;; When an language is embedded, you should initialize some variable
+    ;; just like it's done in the original mode.
+
+    ;; Comment.
+    ;; indenting settings for js-ts-mode.
+    (c-ts-common-comment-setup)
+    (setq-local comment-multi-line t)
+
+    ;; Font-lock.
+
+    ;; There are two kind of treesitter parser:
+    ;; 1. global parser
+    ;; 2. local parser
+    ;; The global parser considers each piece of text,
+    ;; in a multilingual buffer, as if it were a single buffer in its
+    ;; own language. Local parsers, on the other hand, consider each
+    ;; piece of text, in a multilingual buffer, as if they were
+    ;; separate buffers.
+    ;; In a multilingual buffer you should create only global ones.
+    ;; Local ones are created automatically.
+    ;; Warning: do not create a local parser! It may cause side
+    ;; effects that are difficult to handle.
+
+    ;; There are two types of treesitter parsers:
+    ;; 1. global parsers
+    ;; 2. local parsers
+    ;; A global parser treats each piece of text,
+    ;; in a multilingual buffer, as if it were a single buffer in its
+    ;; language. Local parser, on the other hand, treat each
+    ;; piece of text, in a multilingual buffer, as if they were separate buffers.
+    ;; In a multilingual buffer you should only create global ones.
+    ;; The local ones are created automatically.
+    ;; Warning: do not create a local parser! It may cause side effects that are difficult to handle.

Seems like a duplicate? And I want to highlight the fact that we're
talking about embedded parsers here, so I would say:

There are two ways to handle embedded code:
1. Use a single parser for all the embedded code in the buffer. In
this case, the embedded code blocks are concatenated together and are
seen as a single continuous document to the parser.
2. Each embedded code block gets its own parser. Each parser only sees
that particular code block.

If you go with 2 for a language, the local parsers are created and
destroyed automatically by Emacs. So don't create a global parser for
that embedded language here.

+
+    ;; Create the parsers, only the global one.

"only global ones", I think

+    ;; jsdoc is a local parser, don't create a parser for it.
+    (treesit-parser-create 'css)
+    (treesit-parser-create 'javascript)
+
+    ;; jsdoc is not mandatory for js-ts-mode, so we respect this by
+    ;; adding jsdoc range rules only when jsdoc is available.
+    (if (treesit-ready-p 'jsdoc t)
+        (setq-local treesit-range-settings
+                    (treesit-range-rules
+                     :embed 'javascript
+                     :host 'html
+                     :offset '(1 . -1)
+                     '((script_element
+                        (start_tag (tag_name))
+                        (raw_text) @cap))
+
+                     :embed 'jsdoc
+                     :host 'javascript
+                     :local t
+                     `(((comment) @cap
+                        (:match ,js--treesit-jsdoc-beginning-regexp @cap)))
+
+                     :embed 'css
+                     :host 'html
+                     :offset '(1 . -1)
+                     '((style_element
+                        (start_tag (tag_name))
+                        (raw_text) @cap))))
+      (setq-local treesit-range-settings
+                  (treesit-range-rules
+                   :embed 'javascript
+                   :host 'html
+                   :offset '(1 . -1)
+                   '((script_element
+                      (start_tag (tag_name))
+                      (raw_text) @cap))
+
+                   :embed 'css
+                   :host 'html
+                   :offset '(1 . -1)
+                   '((style_element
+                      (start_tag (tag_name))
+                      (raw_text) @cap)))))

You can create range rules for each language and append them, that way
you don't need to duplicate the code here. It's just like the
font-lock settings.

+
+    ;; Many treesit fuctions need to know the language at-point.
+    ;; So you should define such a function.
+    (setq-local treesit-language-at-point-function #'mhtml-ts-mode--language-at-point)
+
+    ;; Indent.
+
+    ;; Since mhtl-ts-mode inherits indentation rules from html-ts-mode, js
+    ;; and css, if you want to change the offset you have to act on the
+    ;; *-offset variables defined for those languages.
+
+    ;; JavaScript and CSS must be indented relative to their code block.
+    ;; This is done by inserting a special rule before the normal
+    ;; indentation rules of these languages.
+    ;; The value of mhtml-ts-mode--js-css-indent-offset changes based on
+    ;; mhtml-ts-mode-tag-relative-indent and can be used to indent
+    ;; JavaScript and CSS code relative to the HTML that contains them,
+    ;; just like in mhtml-mode.
+    (setq-local treesit-simple-indent-rules
+                (append html-ts-mode--indent-rules
+                        ;; Extended rules for js and css, to
+                        ;; indent appropriately when injected
+                        ;; into html
+                        `((javascript ((parent-is "program")
+                                       mhtml-ts-mode--js-css-tag-bol
+                                       mhtml-ts-mode--js-css-indent-offset)
+                                      ,@(cdr (car js--treesit-indent-rules))))
+                        `((css ((parent-is "stylesheet")
+                                mhtml-ts-mode--js-css-tag-bol
+                                mhtml-ts-mode--js-css-indent-offset)
+                               ,@(cdr (car css--treesit-indent-rules))))))
+    ;; Navigation.
+
+    ;; This regular expression tells treesit how to match the node type
+    ;; of defun nodes.
+    ;; Used by `treesit-beginning-of-defun' and friends for
+    ;; navigations.
+    (setq-local treesit-defun-type-regexp
+                (rx (or
+                     ;; Javascript
+                     "class_declaration"
+                     "method_definition"
+                     "function_declaration"
+                     "lexical_declaration"
+                     ;; HTML
+                     "element"
+                     ;; CSS
+                     "rule_set")))

You can actually define a defun "thing" in treesit-thing-setting, and
it should work the same.

+    ;; This is for finding defun name, it's used by IMenu as default
+    ;; function no specific functions are defined.
+    (setq-local treesit-defun-name-function #'mhtml-ts-mode--defun-name)
+
+    ;; Define what are 'thing' for treesit.
+    ;; 'Thing' is a symbol representing the thing, like `defun', `sexp', or
+    ;; `sentence'.
+    (setq-local treesit-thing-settings
+                `((html
+                   (sexp ,(regexp-opt '("element"
+                                        "text"
+                                        "attribute"
+                                        "value")))
+                   (sentence "tag")
+                   (text ,(regexp-opt '("comment" "text"))))
+                  (javascript
+                   (sexp ,(js--regexp-opt-symbol js--treesit-sexp-nodes))
+                   (sentence ,(js--regexp-opt-symbol js--treesit-sentence-nodes))
+                   (text ,(js--regexp-opt-symbol '("comment"
+                                                   "string_fragment"))))))
+
+    ;; Font-lock.
+
+    ;; In a multi-language scenario, font lock settings are usually a
+    ;; concatenation of language rules. As you can see, it is possible
+    ;; to extend/modify the default rule or use a different set of
+    ;; rules. See `php-ts-mode--custom-html-font-lock-settings' for more
+    ;; advanced usage.
+    (setq-local treesit-font-lock-settings
+                (append html-ts-mode--font-lock-settings
+                        js--treesit-font-lock-settings
+                        (append
+                         ;; Rule for coloring CSS property values.
+                         ;; Placed before `css--treesit-settings'
+                         ;; to win against the same rule contained therein.
+                         (treesit-font-lock-rules
+                          :language 'css
+                          :override t
+                          :feature 'variable
+                          '((plain_value) @mhtml-ts-mode--colorize-css-value))
+                         css--treesit-settings)))
+
+    ;; Tells treesit the list of features to fontify.
+    (setq-local treesit-font-lock-feature-list mhtml-ts-mode--feature-list)
+
+    ;; Imenu
+
+    ;; Setup Imenu: if no function is specified, try to find an object
+    ;; using `treesit-defun-name-function'.
+    ;; TODO: we need to see if it is possible to extend Imenu to
+    ;; embedded languages ​​as well.
+    (setq-local treesit-simple-imenu-settings
+                `(("Element" "\\`tag_name\\'" nil nil)))
+
+    ;; This should be the last thing to do.
+    ;; Treesit tries to find out what the primary language is, but it is better
+    ;; to say it explicitly.

Correction: multi-language modes must set the primary parser
explicitly, the auto-guessing trick only works for single-language
modes. You can also move this line next to where you created the other
parsers, for better readability.

+    (setq-local treesit-primary-parser (treesit-parser-create 'html))

+    (treesit-font-lock-recompute-features)

You don't need to call treesit-font-lock-recompute-features,
treesit-major-mode-setup will do that for you.

+    (treesit-major-mode-setup)))
+
+(when (and (treesit-ready-p 'html) (treesit-ready-p 'javascript) (treesit-ready-p 'css))
+  (add-to-list
+   'auto-mode-alist '("\\.[sx]?html?\\(\\.[a-zA-Z_]+\\)?\\'" . mhtml-ts-mode)))
+
+(provide 'mhtml-ts-mode)
+;;; mhtml-ts-mode.el ends here
-- 
2.47.1

bug#74610: 31.0.50; Submitting mhtml-ts-mode, treesitter alternative to mhtml-mode

[Eli Zaretskii]

> Cc: 74610@debbugs.gnu.org
> From: Yuan Fu <casouri@gmail.com>
> Date: Sat, 30 Nov 2024 22:01:21 -0800
> 
> 
> 
> > On Nov 29, 2024, at 1:57 PM, Vincenzo Pupillo <v.pupillo@gmail.com> wrote:
> > 
> > Ciao,
> > following the discussion 
> > https://lists.gnu.org/archive/html/emacs-devel/2024-11/msg00079.html I would 
> > like to ask if it would be possible to add to emacs this new mode for editing 
> > html files alternative to mhtml-mode.
> > 
> > Thank you.
> > 
> > Vincenzo.<0001-Add-mhtml-ts-mode.patch>
> 
> Thank you so much! This will be very helpful for others. Here’re some comments.

Yuan, I don't see any comments, only what I think is the original
patch.

bug#74610: 31.0.50; Submitting mhtml-ts-mode, treesitter alternative to mhtml-mode

[Yuan Fu]

> On Dec 1, 2024, at 12:00 AM, Eli Zaretskii <eliz@gnu.org> wrote:
> 
>> Cc: 74610@debbugs.gnu.org
>> From: Yuan Fu <casouri@gmail.com>
>> Date: Sat, 30 Nov 2024 22:01:21 -0800
>> 
>> 
>> 
>>> On Nov 29, 2024, at 1:57 PM, Vincenzo Pupillo <v.pupillo@gmail.com> wrote:
>>> 
>>> Ciao,
>>> following the discussion 
>>> https://lists.gnu.org/archive/html/emacs-devel/2024-11/msg00079.html I would 
>>> like to ask if it would be possible to add to emacs this new mode for editing 
>>> html files alternative to mhtml-mode.
>>> 
>>> Thank you.
>>> 
>>> Vincenzo.<0001-Add-mhtml-ts-mode.patch>
>> 
>> Thank you so much! This will be very helpful for others. Here’re some comments.
> 
> Yuan, I don't see any comments, only what I think is the original
> patch.

Ah, I guess I’m supposed to quote the original patch when making comments :-( The lines that aren’t prefixed by + are my comments.

Yuan

bug#74610: 31.0.50; Submitting mhtml-ts-mode, treesitter alternative to mhtml-mode

[Vincenzo Pupillo]

In data domenica 1 dicembre 2024 07:01:21 Ora standard dell’Europa centrale, 
Yuan Fu ha scritto:
> It's not uncommon to see different indent offset for CSS and
> Javascript, so it's a good idea to have separate control for them.

Is the behavior the same as mhtml-mode, or would you like something like this?

    <style>
                                  z {
                                      color: red;
                                  }
    </style>
    <script>
        function myFunction(p1, p2) {
            return p1 * p2;
        }
    </script>

The mhtml-ts-mode-js-css-indent-offset variable controls only the indentation 
relative to the <style> and <script> tags.

V.

bug#74610: 31.0.50; Submitting mhtml-ts-mode, treesitter alternative to mhtml-mode

[Dmitry Gutov]

On 29/11/2024 23:57, Vincenzo Pupillo wrote:
> +;; This package provides `mhtml-ts-mode' which is a major mode
> +;; for editing HTML files with embedded JavaScript and CSS.
> +;; Tree Sitter is used to parse each of these languages.
> +;;
> +;; Please note that this package requires `html-ts-mode', which
> +;; registers itself as the major mode for editing HTML.

Hi!

Do you foresee cases for when html-ts-mode would be preferred by the 
user instead of this advanced mhtml-ts-mode? Or maybe the former is 
better in its current shape when used by e.g. php-ts-mode?

In other words, I'm wondering why not update the existing mode with 
sub-parsers rather than add a new one. html-mode had such a reason - 
it's quite old, and has been used in various placed the way it is now 
(including multi-mode packages). But ts modes don't work too well with 
multi-mode packages, not currently anyway.

bug#74610: 31.0.50; Submitting mhtml-ts-mode, treesitter alternative to mhtml-mode

[Vincenzo Pupillo]

Hi Dmitry,

In data mercoledì 4 dicembre 2024 02:27:53 Ora standard dell’Europa centrale, 
hai scritto:
> On 29/11/2024 23:57, Vincenzo Pupillo wrote:
> > +;; This package provides `mhtml-ts-mode' which is a major mode
> > +;; for editing HTML files with embedded JavaScript and CSS.
> > +;; Tree Sitter is used to parse each of these languages.
> > +;;
> > +;; Please note that this package requires `html-ts-mode', which
> > +;; registers itself as the major mode for editing HTML.
> 
> Hi!
> 
> Do you foresee cases for when html-ts-mode would be preferred by the
> user instead of this advanced mhtml-ts-mode? 
For everyday use mhtml-ts-mode is better, just like mhtml-mode (which has been 
the default for html editing for a while now).

> Or maybe the former is
> better in its current shape when used by e.g. php-ts-mode?
Yes, personally I think that major modes that handle (for tree-sitters) only 
one language are easier to put together at the moment. It's Lego vs. 
Playmobil.
We are in an experimental phase, like all other editors.
See https://github.com/helix-editor/helix/pull/1170#issuecomment-997294090
In some ways, by having a different approach from other editors, we have a 
greater degree of flexibility IMHO.

> 
> In other words, I'm wondering why not update the existing mode with
> sub-parsers rather than add a new one. html-mode had such a reason -
> it's quite old, and has been used in various placed the way it is now
> (including multi-mode packages). But ts modes don't work too well with
> multi-mode packages, not currently anyway.

It's something I've thought about but haven't tried yet. 
One of the themes of the email thread (on emacs-devel) was to have a simple 
multi language major mode that was also a sort of “user's guide.”


Vincenzo.

bug#74610: 31.0.50; Submitting mhtml-ts-mode, treesitter alternative to mhtml-mode

[Dmitry Gutov]

Hi Vincenzo,

On 04/12/2024 12:47, Vincenzo Pupillo wrote:

>> Do you foresee cases for when html-ts-mode would be preferred by the
>> user instead of this advanced mhtml-ts-mode?
> For everyday use mhtml-ts-mode is better, just like mhtml-mode (which has been
> the default for html editing for a while now).
> 
>> Or maybe the former is
>> better in its current shape when used by e.g. php-ts-mode?
> Yes, personally I think that major modes that handle (for tree-sitters) only
> one language are easier to put together at the moment. It's Lego vs.
> Playmobil.
> We are in an experimental phase, like all other editors.
> See https://github.com/helix-editor/helix/pull/1170#issuecomment-997294090
> In some ways, by having a different approach from other editors, we have a
> greater degree of flexibility IMHO.

Makes sense, thanks.

>> In other words, I'm wondering why not update the existing mode with
>> sub-parsers rather than add a new one. html-mode had such a reason -
>> it's quite old, and has been used in various placed the way it is now
>> (including multi-mode packages). But ts modes don't work too well with
>> multi-mode packages, not currently anyway.
> 
> It's something I've thought about but haven't tried yet.
> One of the themes of the email thread (on emacs-devel) was to have a simple
> multi language major mode that was also a sort of “user's guide.”

I though the updated html-ts-mode could be that mode. Anyway, good to 
hear that this alternative had been given consideration.

bug#74610: 31.0.50; Submitting mhtml-ts-mode, treesitter alternative to mhtml-mode

[Vincenzo Pupillo]

Ciao Dmitry,

In data giovedì 5 dicembre 2024 17:51:55 Ora standard dell’Europa centrale, 
Dmitry Gutov ha scritto:
> Hi Vincenzo,
> 
> On 04/12/2024 12:47, Vincenzo Pupillo wrote:
> >> Do you foresee cases for when html-ts-mode would be preferred by the
> >> user instead of this advanced mhtml-ts-mode?
> > 
> > For everyday use mhtml-ts-mode is better, just like mhtml-mode (which has
> > been the default for html editing for a while now).
> > 
> >> Or maybe the former is
> >> better in its current shape when used by e.g. php-ts-mode?
> > 
> > Yes, personally I think that major modes that handle (for tree-sitters)
> > only one language are easier to put together at the moment. It's Lego vs.
> > Playmobil.
> > We are in an experimental phase, like all other editors.
> > See https://github.com/helix-editor/helix/pull/1170#issuecomment-997294090
> > In some ways, by having a different approach from other editors, we have a
> > greater degree of flexibility IMHO.
> 
> Makes sense, thanks.
> 
> >> In other words, I'm wondering why not update the existing mode with
> >> sub-parsers rather than add a new one. html-mode had such a reason -
> >> it's quite old, and has been used in various placed the way it is now
> >> (including multi-mode packages). But ts modes don't work too well with
> >> multi-mode packages, not currently anyway.
> > 
> > It's something I've thought about but haven't tried yet.
> > One of the themes of the email thread (on emacs-devel) was to have a
> > simple
> > multi language major mode that was also a sort of “user's guide.”
> 
> I though the updated html-ts-mode could be that mode. Anyway, good to
> hear that this alternative had been given consideration.

Since the development of Emacs 31 has just started and this major mode is not 
urgent, I will try some experiments in the next few days to see if html-ts-
mode can be modified without compromising the integration with php-ts-mode.

Vincenzo

bug#74610: 31.0.50; Submitting mhtml-ts-mode, treesitter alternative to mhtml-mode

[Yuan Fu]

> On Dec 3, 2024, at 6:29 AM, Vincenzo Pupillo <v.pupillo@gmail.com> wrote:
> 
> In data domenica 1 dicembre 2024 07:01:21 Ora standard dell’Europa centrale, 
> Yuan Fu ha scritto:
>> It's not uncommon to see different indent offset for CSS and
>> Javascript, so it's a good idea to have separate control for them.
> 
> Is the behavior the same as mhtml-mode, or would you like something like this?
> 
>    <style>
>                                  z {
>                                      color: red;
>                                  }
>    </style>
>    <script>
>        function myFunction(p1, p2) {
>            return p1 * p2;
>        }
>    </script>
> 
> The mhtml-ts-mode-js-css-indent-offset variable controls only the indentation 
> relative to the <style> and <script> tags.

Ah, I see, it’s the offset from the enclosing tag. In that case it should be fine to use a common variable.

Yuan

bug#74610: 31.0.50; Submitting mhtml-ts-mode, treesitter alternative to mhtml-mode

[Vincenzo Pupillo]

[-- Attachment #1: Type: text/plain, Size: 1529 bytes --]

In data mercoledì 11 dicembre 2024 05:54:09 Ora standard dell’Europa centrale, 
Yuan Fu ha scritto:
> > On Dec 3, 2024, at 6:29 AM, Vincenzo Pupillo <v.pupillo@gmail.com> wrote:
> > 
> > In data domenica 1 dicembre 2024 07:01:21 Ora standard dell’Europa
> > centrale,> 
> > Yuan Fu ha scritto:
> >> It's not uncommon to see different indent offset for CSS and
> >> Javascript, so it's a good idea to have separate control for them.
> > 
> > Is the behavior the same as mhtml-mode, or would you like something like
> > this?> 
> >    <style>
> >    
> >                                  z {
> >                                  
> >                                      color: red;
> >                                  
> >                                  }
> >    
> >    </style>
> >    <script>
> >    
> >        function myFunction(p1, p2) {
> >        
> >            return p1 * p2;
> >        
> >        }
> >    
> >    </script>
> > 
> > The mhtml-ts-mode-js-css-indent-offset variable controls only the
> > indentation relative to the <style> and <script> tags.
> 
> Ah, I see, it’s the offset from the enclosing tag. In that case it should be
> fine to use a common variable.
> 
> Yuan
Thank you Yuan.
Attached is the revised patch following your previous comments.
As I already wrote to Dmitry, I am doing some tests to see if html-ts-mode can 
be extended and if there is a way to integrate one multi-language mode into 
another multi-language mode.

Vincenzo

[-- Attachment #2: 0001-Add-mhtml-ts-mode.patch --]
[-- Type: text/x-patch, Size: 19855 bytes --]

From 355075793eff5a58dac83756d96881b6932d5838 Mon Sep 17 00:00:00 2001
From: Vincenzo Pupillo <v.pupillo@gmail.com>
Date: Fri, 29 Nov 2024 22:48:45 +0100
Subject: [PATCH] Add mhtml-ts-mode.

New major-mode alternative to mhtml-mode, based on treesitter, for
editing files containing html, javascript and css.

* etc/NEWS: Mention the new mode.
* lisp/textmodes/mhtml-ts-mode.el: New file.
---
 etc/NEWS                        |   8 +
 lisp/textmodes/mhtml-ts-mode.el | 429 ++++++++++++++++++++++++++++++++
 2 files changed, 437 insertions(+)
 create mode 100644 lisp/textmodes/mhtml-ts-mode.el

diff --git a/etc/NEWS b/etc/NEWS
index 4d2a2c893d0..8f9a04dcf01 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -797,6 +797,14 @@ destination window is chosen using 'display-buffer-alist'.  Example:
 \f
 * New Modes and Packages in Emacs 31.1
 
+** New major modes based on the tree-sitter library
+
++++
+*** New major mode 'mhtml-ts-mode'.
+An optional major mode based on the tree-sitter library for editing html
+files. This mode handles indentation, fontification, and commenting for
+embedded JavaScript and CSS.
+
 \f
 * Incompatible Lisp Changes in Emacs 31.1
 
diff --git a/lisp/textmodes/mhtml-ts-mode.el b/lisp/textmodes/mhtml-ts-mode.el
new file mode 100644
index 00000000000..746300efc33
--- /dev/null
+++ b/lisp/textmodes/mhtml-ts-mode.el
@@ -0,0 +1,429 @@
+;;; mhtml-ts-mode.el --- Major mode for HTML using tree-sitter -*- lexical-binding: t; -*-
+
+;; Copyright (C) 2024 Free Software Foundation, Inc.
+
+;; Author: Vincenzo Pupillo <v.pupillo@gmail.com>
+;; Maintainer: Vincenzo Pupillo <v.pupillo@gmail.com>
+;; Created: Nov 2024
+;; Keywords: HTML language 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 <https://www.gnu.org/licenses/>.
+
+;;; Commentary:
+;;
+;; This package provides `mhtml-ts-mode' which is a major mode
+;; for editing HTML files with embedded JavaScript and CSS.
+;; Tree Sitter is used to parse each of these languages.
+;;
+;; Please note that this package requires `html-ts-mode', which
+;; registers itself as the major mode for editing HTML.
+;;
+;; This package is compatible and has been tested with the following
+;; tree-sitter grammars:
+;; * https://github.com/tree-sitter/tree-sitter-html
+;; * https://github.com/tree-sitter/tree-sitter-javascript
+;; * https://github.com/tree-sitter/tree-sitter-jsdoc
+;; * https://github.com/tree-sitter/tree-sitter-css
+;;
+;; Features
+;;
+;; * Indent
+;; * IMenu
+;; * Navigation
+;; * Which-function
+;; * Tree-sitter parser installation helper
+
+;;; Code:
+
+(require 'treesit)
+(require 'html-ts-mode)
+(require 'css-mode) ;; for embed css into html
+(require 'js) ;; for embed javascript into html
+
+(eval-when-compile
+  (require 'rx))
+
+;; This tells the byte-compiler where the functions are defined.
+;; Is only needed when a file needs to be able to byte-compile
+;; in a Emacs not built with tree-sitter library.
+(treesit-declare-unavailable-functions)
+
+;; In a multi-language major mode can be useful to have an "installer" to
+;; simplify the installation of the grammars supported by the major-mode.
+(defvar mhtml-ts-mode--language-source-alist
+  '((html . ("https://github.com/tree-sitter/tree-sitter-html"  "v0.23.0"))
+    (javascript . ("https://github.com/tree-sitter/tree-sitter-javascript" "v0.23.0"))
+    (jsdoc . ("https://github.com/tree-sitter/tree-sitter-jsdoc" "v0.23.0"))
+    (css . ("https://github.com/tree-sitter/tree-sitter-css" "v0.23.0")))
+  "Treesitter language parsers required by `mhtml-ts-mode'.
+You can customize this variable if you want to stick to a specific
+commit and/or use different parsers.")
+
+(defun mhtml-ts-mode-install-parsers ()
+  "Install all the required treesitter parsers.
+`mhtml-ts-mode--language-source-alist' defines which parsers to install."
+  (interactive)
+  (let ((treesit-language-source-alist mhtml-ts-mode--language-source-alist))
+    (dolist (item mhtml-ts-mode--language-source-alist)
+      (treesit-install-language-grammar (car item)))))
+
+;;; Custom variables
+
+(defgroup mhtml-ts-mode nil
+  "Major mode for editing HTML files, based on `html-ts-mode'.
+Works with JS and CSS and for that use `js-ts-mode' and `css-ts-mode'."
+  :prefix "mhtml-ts-mode-"
+  ;; :group 'languages
+  :group 'html)
+
+(defcustom mhtml-ts-mode-js-css-indent-offset 2
+  "JavaScript and CSS indent spaces related to the <script> and <style> HTML tags.
+By default should have same value as `html-ts-mode-indent-offset'."
+  :tag "HTML javascript or css indent offset"
+  :version "31.1"
+  :type 'integer
+  :safe 'integerp)
+
+(defvar mhtml-ts-mode--js-css-indent-offset
+  mhtml-ts-mode-js-css-indent-offset
+  "Internal copy of `mhtml-ts-mode-js-css-indent-offset'.
+The value changes, by `mhtml-ts-mode--tag-relative-indent-offset' according to
+the value of `mhtml-ts-mode-tag-relative-indent'.")
+
+(defun mhtml-ts-mode--tag-relative-indent-offset (sym val)
+  "Custom setter for `mhtml-ts-mode-tag-relative-indent'.
+
+Apart from setting the default value of SYM to VAL, also change the
+value of SYM in `mhtml-ts-mode' buffers to VAL.  SYM should be
+`mhtml-ts-mode-tag-relative-indent', and VAL should be t, nil or
+`ignore'.  When sym is `mhtml-ts-mode-tag-relative-indent' set the
+value of `mhtml-ts-mode--js-css-indent-offset' to 0 if VAL is t,
+otherwise to `mhtml-ts-mode-js-css-indent-offset'."
+  (set-default sym val)
+  (when (eq sym 'mhtml-ts-mode-tag-relative-indent)
+    (setq-local
+     mhtml-ts-mode--js-css-indent-offset
+     (if (eq val t)
+         mhtml-ts-mode-js-css-indent-offset
+       0))))
+
+(defcustom mhtml-ts-mode-tag-relative-indent t
+  "How <script> and <style> bodies are indented relative to the tag.
+
+When t, indentation looks like:
+
+  <script>
+    code();
+  </script>
+
+When nil, indentation of the script body starts just below the
+tag, like:
+
+  <script>
+  code();
+  </script>
+
+When `ignore', the script body starts in the first column, like:
+
+  <script>
+code();
+  </script>"
+  :type '(choice (const nil) (const t) (const ignore))
+  :safe 'symbolp
+  :set #'mhtml-ts-mode--tag-relative-indent-offset
+  :version "31.1")
+
+(defcustom mhtml-ts-mode-css-fontify-colors t
+  "Whether CSS colors should be fontified using the color as the background.
+If non-nil, text representing a CSS color will be fontified
+such that its background is the color itself.
+Works like `css--fontify-region'."
+  :tag "HTML colors the CSS properties values."
+  :version "31.1"
+  :type 'boolean
+  :safe 'booleanp)
+
+;; To enable some basic treesiter functionality, you should define
+;; a function that recognizes which grammar is used at-point.
+;; This function should be assigned to `treesit-language-at-point-function'
+(defun mhtml-ts-mode--language-at-point (point)
+  "Return the language at POINT assuming the point is within a HTML buffer."
+  (let* ((node (treesit-node-at point 'html))
+         (parent (treesit-node-parent node))
+         (node-query (format "(%s (%s))"
+                             (treesit-node-type parent)
+                             (treesit-node-type node))))
+    (cond
+     ((string-equal "(script_element (raw_text))" node-query) 'javascript)
+     ((string-equal "(style_element (raw_text))" node-query) 'css)
+     (t 'html))))
+
+;; Custom font-lock function that's used to apply color to css color
+;; The signature of the function should be conforming to signature
+;; QUERY-SPEC required by `treesit-font-lock-rules'.
+(defun mhtml-ts-mode--colorize-css-value (node override start end &rest _)
+  "Colorize CSS property value like `css--fontify-region'.
+For NODE, OVERRIDE, START, and END, see `treesit-font-lock-rules'."
+  (if (and mhtml-ts-mode-css-fontify-colors
+           (string-equal "plain_value" (treesit-node-type node)))
+      (let ((color (css--compute-color start (treesit-node-text node t))))
+        (when color
+          (with-silent-modifications
+            (add-text-properties
+             (treesit-node-start node) (treesit-node-end node)
+             (list 'face (list :background color
+                               :foreground (readable-foreground-color
+                                            color)
+                               :box '(:line-width -1)))))))
+    (treesit-fontify-with-override
+     (treesit-node-start node) (treesit-node-end node)
+     'font-lock-variable-name-face
+     override start end)))
+
+;; Embedded languages ​​should be indented according to the language
+;; that embeds them.
+;; This function signature complies with `treesit-simple-indent-rules'
+;; ANCHOR.
+(defun mhtml-ts-mode--js-css-tag-bol (_node _parent &rest _)
+  "Find the first non-space characters of html tags <script> or <style>.
+Return `line-beginning-position' when `treesit-node-at' is html, or
+`mhtml-ts-mode-tag-relative-indent' is equal to ignore.
+NODE and PARENT are ignored."
+  (if (or (eq (treesit-language-at (point)) 'html)
+          (eq mhtml-ts-mode-tag-relative-indent 'ignore))
+      (line-beginning-position)
+    ;; Ok, we are in js or css block.
+    (save-excursion
+      (re-search-backward "<script.*>\\|<style.*>" nil t))))
+
+;; Treesit supports 4 level of decoration, `treesit-font-lock-level'
+;; define which level to use.  Major modes categorize their fontification
+;; features, these categories are defined by `treesit-font-lock-rules' of
+;; each major-mode using :feature keyword.
+;; In a multiple language Major mode it's a good idea to provide, for each
+;; level, the union of the :feature of the same level.
+(defvar mhtml-ts-mode--feature-list
+  '(;; level 1
+    (;; common
+     comment definition
+     ;; JS specific
+     document
+     ;; CSS specific
+     query selector)
+    ;; level 2
+    (keyword name property string type)
+    ;; level 3
+    (;; common
+     attribute assignment constant escape-sequence
+     base-clause literal variable-name variable
+     ;; Javascript specific
+     jsx number pattern string-interpolation)
+    ;; level 4
+    (bracket delimiter error operator function)))
+
+;; In order to support `which-fuction-mode' we should define
+;; a function that return the defun name.
+;; In a multilingual treesit mode, this can be implemented simply by
+;; calling language-specific functions.
+(defun mhtml-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."
+  (let ((lang (mhtml-ts-mode--language-at-point (point))))
+    (message "lang = %s" lang)
+    (cond
+     ((eq lang 'html) (html-ts-mode--defun-name node))
+     ((eq lang 'javascript) (js--treesit-defun-name node))
+     ((eq lang 'css) (css--treesit-defun-name node)))))
+
+(define-derived-mode mhtml-ts-mode html-mode
+  '("HTML+" (:eval (let ((lang (mhtml-ts-mode--language-at-point (point))))
+                     (cond ((eq lang 'html) "")
+                           ((eq lang 'javascript) "JS")
+                           ((eq lang 'css) "CSS")))))
+  "Major mode for editing HTML with embedded JavaScript and CSS.
+Powered by tree-sitter."
+  (if (not (and
+            (treesit-ready-p 'html)
+            (treesit-ready-p 'javascript)
+            (treesit-ready-p 'css)))
+      (error "Tree-sitter parsers for HTML isn't
+    available.  You can install the parsers with M-x
+    `mhtml-ts-mode-install-parsers'")
+
+    ;; When an language is embedded, you should initialize some variable
+    ;; just like it's done in the original mode.
+
+    ;; Comment.
+    ;; indenting settings for js-ts-mode.
+    (c-ts-common-comment-setup)
+    (setq-local comment-multi-line t)
+
+    ;; Font-lock.
+
+    ;; There are two ways to handle embedded code:
+    ;; 1. Use a single parser for all the embedded code in the buffer. In
+    ;; this case, the embedded code blocks are concatenated together and are
+    ;; seen as a single continuous document to the parser.
+    ;; 2. Each embedded code block gets its own parser. Each parser only sees
+    ;; that particular code block.
+
+    ;; If you go with 2 for a language, the local parsers are created and
+    ;; destroyed automatically by Emacs. So don't create a global parser for
+    ;; that embedded language here.
+
+    ;; Create the parsers, only the global ones.
+    ;; jsdoc is a local parser, don't create a parser for it.
+    (treesit-parser-create 'css)
+    (treesit-parser-create 'javascript)
+
+    ;; Multi-language modes must set the  primary parser.
+    (setq-local treesit-primary-parser (treesit-parser-create 'html))
+
+    (setq-local treesit-range-settings
+                (treesit-range-rules
+                 :embed 'javascript
+                 :host 'html
+                 :offset '(1 . -1)
+                 '((script_element
+                    (start_tag (tag_name))
+                    (raw_text) @cap))
+
+                 :embed 'css
+                 :host 'html
+                 :offset '(1 . -1)
+                 '((style_element
+                    (start_tag (tag_name))
+                    (raw_text) @cap))))
+
+    ;; jsdoc is not mandatory for js-ts-mode, so we respect this by
+    ;; adding jsdoc range rules only when jsdoc is available.
+    (when (treesit-ready-p 'jsdoc t)
+      (setq-local treesit-range-settings
+                  (append treesit-range-settings
+                          (treesit-range-rules
+                           :embed 'jsdoc
+                           :host 'javascript
+                           :local t
+                           `(((comment) @cap
+                              (:match ,js--treesit-jsdoc-beginning-regexp @cap))))))
+      (setq-local c-ts-common--comment-regexp
+            (rx (or "comment" "line_comment" "block_comment" "description"))))
+
+
+    ;; Many treesit fuctions need to know the language at-point.
+    ;; So you should define such a function.
+    (setq-local treesit-language-at-point-function #'mhtml-ts-mode--language-at-point)
+
+    ;; Indent.
+
+    ;; Since mhtl-ts-mode inherits indentation rules from html-ts-mode, js
+    ;; and css, if you want to change the offset you have to act on the
+    ;; *-offset variables defined for those languages.
+
+    ;; JavaScript and CSS must be indented relative to their code block.
+    ;; This is done by inserting a special rule before the normal
+    ;; indentation rules of these languages.
+    ;; The value of mhtml-ts-mode--js-css-indent-offset changes based on
+    ;; mhtml-ts-mode-tag-relative-indent and can be used to indent
+    ;; JavaScript and CSS code relative to the HTML that contains them,
+    ;; just like in mhtml-mode.
+    (setq-local treesit-simple-indent-rules
+                (append html-ts-mode--indent-rules
+                        ;; Extended rules for js and css, to
+                        ;; indent appropriately when injected
+                        ;; into html
+                        `((javascript ((parent-is "program")
+                                       mhtml-ts-mode--js-css-tag-bol
+                                       mhtml-ts-mode--js-css-indent-offset)
+                                      ,@(cdr (car js--treesit-indent-rules))))
+                        `((css ((parent-is "stylesheet")
+                                mhtml-ts-mode--js-css-tag-bol
+                                mhtml-ts-mode--js-css-indent-offset)
+                               ,@(cdr (car css--treesit-indent-rules))))))
+    ;; Navigation.
+
+    ;; This is for finding defun name, it's used by IMenu as default
+    ;; function no specific functions are defined.
+    (setq-local treesit-defun-name-function #'mhtml-ts-mode--defun-name)
+
+    ;; Define what are 'thing' for treesit.
+    ;; 'Thing' is a symbol representing the thing, like `defun', `sexp', or
+    ;; `sentence'.
+    ;; As an alternative, if you want just defun, you can define a `treesit-defun-type-regexp'.
+    (setq-local treesit-thing-settings
+                `((html
+                   (defun "element")
+                   (sexp ,(regexp-opt '("element"
+                                        "text"
+                                        "attribute"
+                                        "value")))
+                   (sentence "tag")
+                   (text ,(regexp-opt '("comment" "text"))))
+                  (javascript
+                   (defun ,(rx (or "class_declaration"
+                                   "method_definition"
+                                   "function_declaration"
+                                   "lexical_declaration")))
+                   (sexp ,(regexp-opt js--treesit-sexp-nodes 'symbols))
+                   (sentence ,(regexp-opt js--treesit-sentence-nodes 'symbols))
+                   (text ,(regexp-opt
+                           '("comment"
+                             "string_fragment")
+                           'symbols)))
+                  (css
+                   (defun "rule_set"))))
+
+    ;; Font-lock.
+
+    ;; In a multi-language scenario, font lock settings are usually a
+    ;; concatenation of language rules. As you can see, it is possible
+    ;; to extend/modify the default rule or use a different set of
+    ;; rules. See `php-ts-mode--custom-html-font-lock-settings' for more
+    ;; advanced usage.
+    (setq-local treesit-font-lock-settings
+                (append html-ts-mode--font-lock-settings
+                        js--treesit-font-lock-settings
+                        (append
+                         ;; Rule for coloring CSS property values.
+                         ;; Placed before `css--treesit-settings'
+                         ;; to win against the same rule contained therein.
+                         (treesit-font-lock-rules
+                          :language 'css
+                          :override t
+                          :feature 'variable
+                          '((plain_value) @mhtml-ts-mode--colorize-css-value))
+                         css--treesit-settings)))
+
+    ;; Tells treesit the list of features to fontify.
+    (setq-local treesit-font-lock-feature-list mhtml-ts-mode--feature-list)
+
+    ;; Imenu
+
+    ;; Setup Imenu: if no function is specified, try to find an object
+    ;; using `treesit-defun-name-function'.
+    ;; TODO: we need to see if it is possible to extend Imenu to
+    ;; embedded languages ​​as well.
+    (setq-local treesit-simple-imenu-settings
+                `(("Element" "\\`tag_name\\'" nil nil)))
+
+    (treesit-major-mode-setup)))
+
+(when (and (treesit-ready-p 'html) (treesit-ready-p 'javascript) (treesit-ready-p 'css))
+  (add-to-list
+   'auto-mode-alist '("\\.[sx]?html?\\(\\.[a-zA-Z_]+\\)?\\'" . mhtml-ts-mode)))
+
+(provide 'mhtml-ts-mode)
+;;; mhtml-ts-mode.el ends here
-- 
2.47.1

bug#74610: 31.0.50; Submitting mhtml-ts-mode, treesitter alternative to mhtml-mode

[Juri Linkov]

Ciao Vincenzo,

> In data mercoledì 11 dicembre 2024 05:54:09 Ora standard dell’Europa centrale, 
>
> Attached is the revised patch following your previous comments.
> As I already wrote to Dmitry, I am doing some tests to see if html-ts-mode can 
> be extended and if there is a way to integrate one multi-language mode into 
> another multi-language mode.

I'm testing your patch with mhtml-ts-mode, and everything works nicely.

At the same time I'm adding a new ts-thing named 'sexp-list' in bug#73404.
While 'sexp' defines both lists and atoms, 'sexp-list' defines only lists.

So I added (sexp-list ,(regexp-opt '("element")) 'symbols)
to treesit-thing-settings in html-ts-mode.el.

But then discovered surprisingly that it has no effect on mhtml-ts-mode.

The problem is that treesit-thing-settings should be duplicated
from html-ts-mode to mhtml-ts-mode.
                 
On the one hand, integrating multi-language mode to the exiting mode
html-ts-mode could avoid the need to duplicate treesit-thing-settings
for html.

But on the other hand, integrating mhtml-ts-mode to html-ts-mode
doesn't help to avoid such duplication for other embedded modes.
Because I needed to duplicate treesit-thing-settings for javascript
as well.

So extending html-ts-mode doesn't help here, and maybe even better
to add mhtml-ts-mode to keep the symmetry with existing mhtml-mode
such as used in mode remapping:

  (add-to-list 'major-mode-remap-alist '(mhtml-mode .
                                         mhtml-ts-mode))

What could really help is to try to get settings from html-ts-mode
and js-ts-mode to avoid the need to duplicate settings in mhtml-ts-mode.