emacs/lisp/progmodes/heex-ts-mode.el

199 lines
6.8 KiB
EmacsLisp

;;; heex-ts-mode.el --- Major mode for Heex with tree-sitter support -*- lexical-binding: t; -*-
;; Copyright (C) 2022-2024 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-thing-settings
`((heex
(text ,(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)))
;; Outline minor mode
;; `heex-ts-mode' inherits from `html-mode' that sets
;; regexp-based outline variables. So need to restore
;; the default values of outline variables to be able
;; to use `treesit-outline-predicate' derived
;; from `treesit-simple-imenu-settings' above.
(kill-local-variable 'outline-heading-end-regexp)
(kill-local-variable 'outline-regexp)
(kill-local-variable 'outline-level)
(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)))
(derived-mode-add-parents 'heex-ts-mode '(heex-mode))
(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