Package: emacs;
Reported by: Vincenzo Pupillo <v.pupillo <at> gmail.com>
Date: Fri, 29 Nov 2024 21:58:01 UTC
Severity: wishlist
Fixed in version 31.0.50
Done: Juri Linkov <juri <at> linkov.net>
Bug is archived. No further changes may be made.
View this message in rfc822 format
From: Yuan Fu <casouri <at> gmail.com> To: Vincenzo Pupillo <v.pupillo <at> gmail.com> Cc: 74610 <at> debbugs.gnu.org Subject: bug#74610: 31.0.50; Submitting mhtml-ts-mode, treesitter alternative to mhtml-mode Date: Sat, 30 Nov 2024 22:01:21 -0800
> On Nov 29, 2024, at 1:57 PM, Vincenzo Pupillo <v.pupillo <at> 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 <at> 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:
* 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.
+
* 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 <at> gmail.com>
+;; Maintainer: Vincenzo Pupillo <v.pupillo <at> 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
GNU bug tracking system
Copyright (C) 1999 Darren O. Benham,
1997,2003 nCipher Corporation Ltd,
1994-97 Ian Jackson.