--- /dev/null
+;;; heex-ts-mode.el --- Major mode for Heex with tree-sitter support -*- lexical-binding: t; -*-
+
+;; Copyright (C) 2022-2023 Free Software Foundation, Inc.
+
+;; Author: Wilhelm H Kirschbaum <wkirschbaum@gmail.com>
+;; Created: November 2022
+;; Keywords: elixir languages tree-sitter
+
+;; This file is part of GNU Emacs.
+
+;; GNU Emacs is free software: you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation, either version 3 of the License, or
+;; (at your option) any later version.
+
+;; GNU Emacs is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with GNU Emacs. If not, see <https://www.gnu.org/licenses/>.
+
+;;; Commentary:
+;;
+;; This package provides `heex-ts-mode' which is a major mode for editing
+;; HEEx files that uses Tree Sitter to parse the language.
+;;
+;; This package is compatible with and was tested against the tree-sitter grammar
+;; for HEEx found at https://github.com/phoenixframework/tree-sitter-heex.
+
+;;; Code:
+
+(require 'treesit)
+(eval-when-compile (require 'rx))
+
+(declare-function treesit-parser-create "treesit.c")
+(declare-function treesit-node-child "treesit.c")
+(declare-function treesit-node-type "treesit.c")
+(declare-function treesit-node-start "treesit.c")
+
+(defgroup heex-ts nil
+ "Major mode for editing HEEx code."
+ :prefix "heex-ts-"
+ :group 'langauges)
+
+(defcustom heex-ts-indent-offset 2
+ "Indentation of HEEx statements."
+ :version "30.1"
+ :type 'integer
+ :safe 'integerp
+ :group 'heex-ts)
+
+(defconst heex-ts--sexp-regexp
+ (rx bol
+ (or "directive" "tag" "component" "slot"
+ "attribute" "attribute_value" "quoted_attribute_value")
+ eol))
+
+;; There seems to be no parent directive block for tree-sitter-heex,
+;; so we ignore them for now until we learn how to query them.
+;; https://github.com/phoenixframework/tree-sitter-heex/issues/28
+(defvar heex-ts--indent-rules
+ (let ((offset heex-ts-indent-offset))
+ `((heex
+ ((parent-is "fragment")
+ (lambda (node parent &rest _)
+ ;; If HEEx is embedded indent to parent
+ ;; otherwise indent to the bol.
+ (if (eq (treesit-language-at (point-min)) 'heex)
+ (point-min)
+ (save-excursion
+ (goto-char (treesit-node-start parent))
+ (back-to-indentation)
+ (point))
+ )) 0)
+ ((node-is "end_tag") parent-bol 0)
+ ((node-is "end_component") parent-bol 0)
+ ((node-is "end_slot") parent-bol 0)
+ ((node-is "/>") parent-bol 0)
+ ((node-is ">") parent-bol 0)
+ ((parent-is "comment") prev-adaptive-prefix 0)
+ ((parent-is "component") parent-bol ,offset)
+ ((parent-is "tag") parent-bol ,offset)
+ ((parent-is "start_tag") parent-bol ,offset)
+ ((parent-is "component") parent-bol ,offset)
+ ((parent-is "start_component") parent-bol ,offset)
+ ((parent-is "slot") parent-bol ,offset)
+ ((parent-is "start_slot") parent-bol ,offset)
+ ((parent-is "self_closing_tag") parent-bol ,offset)
+ (no-node parent-bol ,offset)))))
+
+(defvar heex-ts--font-lock-settings
+ (when (treesit-available-p)
+ (treesit-font-lock-rules
+ :language 'heex
+ :feature 'heex-comment
+ '((comment) @font-lock-comment-face)
+ :language 'heex
+ :feature 'heex-doctype
+ '((doctype) @font-lock-doc-face)
+ :language 'heex
+ :feature 'heex-tag
+ `([(tag_name) (slot_name)] @font-lock-function-name-face)
+ :language 'heex
+ :feature 'heex-attribute
+ `((attribute_name) @font-lock-variable-name-face)
+ :language 'heex
+ :feature 'heex-keyword
+ `((special_attribute_name) @font-lock-keyword-face)
+ :language 'heex
+ :feature 'heex-string
+ `([(attribute_value) (quoted_attribute_value)] @font-lock-constant-face)
+ :language 'heex
+ :feature 'heex-component
+ `([
+ (component_name) @font-lock-function-name-face
+ (module) @font-lock-keyword-face
+ (function) @font-lock-keyword-face
+ "." @font-lock-keyword-face
+ ])))
+ "Tree-sitter font-lock settings.")
+
+(defun heex-ts--defun-name (node)
+ "Return the name of the defun NODE.
+Return nil if NODE is not a defun node or doesn't have a name."
+ (pcase (treesit-node-type node)
+ ((or "component" "slot" "tag")
+ (string-trim
+ (treesit-node-text
+ (treesit-node-child (treesit-node-child node 0) 1) nil)))
+ (_ nil)))
+
+(defun heex-ts--forward-sexp (&optional arg)
+ "Move forward across one balanced expression (sexp).
+With ARG, do it many times. Negative ARG means move backward."
+ (or arg (setq arg 1))
+ (funcall
+ (if (> arg 0) #'treesit-end-of-thing #'treesit-beginning-of-thing)
+ heex-ts--sexp-regexp
+ (abs arg)))
+
+;;;###autoload
+(define-derived-mode heex-ts-mode html-mode "HEEx"
+ "Major mode for editing HEEx, powered by tree-sitter."
+ :group 'heex-ts
+
+ (when (treesit-ready-p 'heex)
+ (treesit-parser-create 'heex)
+
+ ;; Comments
+ (setq-local treesit-text-type-regexp
+ (regexp-opt '("comment" "text")))
+
+ (setq-local forward-sexp-function #'heex-ts--forward-sexp)
+
+ ;; Navigation.
+ (setq-local treesit-defun-type-regexp
+ (rx bol (or "component" "tag" "slot") eol))
+ (setq-local treesit-defun-name-function #'heex-ts--defun-name)
+
+ ;; Imenu
+ (setq-local treesit-simple-imenu-settings
+ '(("Component" "\\`component\\'" nil nil)
+ ("Slot" "\\`slot\\'" nil nil)
+ ("Tag" "\\`tag\\'" nil nil)))
+
+ (setq-local treesit-font-lock-settings heex-ts--font-lock-settings)
+
+ (setq-local treesit-simple-indent-rules heex-ts--indent-rules)
+
+ (setq-local treesit-font-lock-feature-list
+ '(( heex-comment heex-keyword heex-doctype )
+ ( heex-component heex-tag heex-attribute heex-string )
+ () ()))
+
+ (treesit-major-mode-setup)))
+
+(if (treesit-ready-p 'heex)
+ ;; Both .heex and the deprecated .leex files should work
+ ;; with the tree-sitter-heex grammar.
+ (add-to-list 'auto-mode-alist '("\\.[hl]?eex\\'" . heex-ts-mode)))
+
+(provide 'heex-ts-mode)
+;;; heex-ts-mode.el ends here
projects / emacs.git / commitdiff