php-ts-mode.el

;;; php-ts-mode.el --- Tree-sitter support for PHP   -*- lexical-binding: t; -*-

;; Copyright (C) 2022-2023 Free Software Foundation, Inc.
;; Copyright (C) 2023  Friends of Emacs-PHP development

;; Author: USAMI Kenta <tadsan@zonu.me>
;; Created: 01 Apr 2023
;; URL: https://github.com/emacs-php/php-ts-mode
;; Version: 0.0.1
;; Package-Requires: ((emacs "29.0"))
;; License: GPL-3.0-or-later
;; Keywords: languages, php, tree-sitter

;; This program 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.

;; This program 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 this program.  If not, see <https://www.gnu.org/licenses/>.

;;; Commentary:

;; A Tree-sitter based major mode for editing PHP codes.

;;; Code:
(eval-when-compile
  (require 'cc-mode)
  (require 'cl-lib))
(require 'treesit)
(require 'c-ts-common)

(declare-function treesit-parser-create "treesit.c")
(declare-function treesit-induce-sparse-tree "treesit.c")
(declare-function treesit-node-child "treesit.c")
(declare-function treesit-node-child-by-field-name "treesit.c")
(declare-function treesit-node-start "treesit.c")
(declare-function treesit-node-type "treesit.c")
(declare-function treesit-search-subtree "treesit.c")

(defcustom php-ts-mode-indent-offset 4
  "Number of spaces for each indentation step in `php-ts-mode'."
  :version "29.1"
  :type 'integer
  :safe 'integerp
  :group 'php)

(defvar php-ts-mode--syntax-table
  (eval-when-compile
    (let ((table (make-syntax-table)))
      (c-populate-syntax-table table)
      (modify-syntax-entry ?_ "w" table)
      (modify-syntax-entry ?`  "\"" table)
      (modify-syntax-entry ?\" "\"" table)
      (modify-syntax-entry ?#  "< b" table)
      (modify-syntax-entry ?\n "> b" table)
      table)))

(defvar php-ts-mode--indent-rules
  (let ((offset php-ts-mode-indent-offset))
    `((php
       ((parent-is "program") column-0 0)
       ((parent-is "function_definition") parent-bol ,offset)
       ((parent-is "if_statement") parent-bol ,offset)
       )))
  "Tree-sitter indent rules.")

(defvar php-ts-mode--keywords
  '("abstract" "as" "break" "case" "catch" "class" "const"
    "continue" "declare" "default" "do" "echo" "else"
    "elseif" "enddeclare" "endforeach" "endif" "endswitch"
    "endwhile" "enum" "extends" "final" "finally" "for" "foreach"
    "fn" "function" "global" "if" "implements" "include_once"
    "include" "insteadof" "interface" "namespace" "never" "new"
    "private" "protected" "public" "readonly" "require_once" "require"
    "return" "static" "switch" "throw" "trait" "try" "use"
    "while" "yield" "yield from")
  "PHP keywords for tree-sitter font-locking.")

(defvar php-ts-mode--operators
  '(("!=" "!==" "%" "%=" "&" "&&" "&=" "*" "**" "*="
     "+" "++" "+=" "," "-" "-" "--" "-=" "->" "."
     ".=" "/" "/=" ":" "::" "<" "<<" "<<=" "<=" "<=>"
     "<>" "=" "==" "===" "=>" ">" ">=" ">>" ">>=" "?"
     "??" "??=" "?->" "@" "\\" "^" "^=" "|" "|=" "||"))
  "PHP operators for tree-sitter font-locking.")

(defconst php-ts-mode--magical-constants
  (list "__CLASS__" "__DIR__" "__FILE__" "__FUNCTION__" "__LINE__" "__METHOD__" "__NAMESPACE__" "__TRAIT__")
  "Magical keyword that is expanded at compile time.

These are different from \"constants\" in strict terms.
see https://www.php.net/manual/language.constants.predefined.php")


(defun php-ts-mode--string-highlight-helper ()
  "Return, for strings, a query based on what is supported by
the available version of Tree-sitter for PHP."
  (condition-case nil
      (progn (treesit-query-capture 'php '((text_block) @font-lock-string-face))
	     `((string_literal) @font-lock-string-face
	       (text_block) @font-lock-string-face))
    (error
     `((string_literal) @font-lock-string-face))))

(defvar php-ts-mode--font-lock-settings
  (treesit-font-lock-rules

   :language 'php
   :feature 'preprocessor
   `((php_tag) @font-lock-preprocessor-face
     ("?>") @font-lock-preprocessor-face)

   :language 'php
   :feature 'type
   `([(primitive_type)
      (cast_type)
      (named_type (name) @type)
      (named_type (qualified_name) @type)
      (namespace_use_clause)
      (namespace_name (name))
      (class_interface_clause (name))
      (const_element (name))
      (boolean)] @font-lock-type-face
      (null) @php-constant
      [(integer)
       (float)] @font-lock-number-face)

   :language 'php
   :feature 'definition
   `((class_declaration
      name: (name) @font-lock-type-face)
     (interface_declaration
      name: (name) @font-lock-type-face)
     (enum_declaration
      name: (name) @font-lock-type-face)
     (trait_declaration
      name: (name) @font-lock-type-face)
     (enum_case
      name: (name) @font-lock-type-face))

   :language 'php
   :feature 'function
   `((array_creation_expression "array") @font-lock-builtin-face
     (list_literal "list") @font-lock-builtin-face

     (method_declaration
      name: (name) @font-lock-function-name-face)

     (function_call_expression
      function: [(qualified_name (name)) (name)] @font-lock-function-call-face)

     (scoped_call_expression
      name: (name) @font-lock-function-call-face)

     (member_call_expression
      name: (name) @font-lock-function-call-face)

     (function_definition
      name: (name) @font-lock-function-name-face))

   :language 'php
   :feature 'variables
   `((relative_scope) @font-lock-builtin-face

     ((name) @font-lock-constant-face
      (:match ,(rx bos (? "_") (in "A-Z") (in "0-9A-Z_") eos)
              @font-lock-constant-face))
     ((name) @font-lock-builtin-face
      (:match ,(rx-to-string `(: bos (or ,@php-ts-mode--magical-constants) eos))
              @font-lock-builtin-face))

     ;; ((name) @constructor
     ;;  (:match ,(rx-to-string '(: bos (in "A-Z")))))

     ;; ((name) @font-lock-variable-name-face
     ;;  (#eq? @php-$this "this"))

     (variable_name) @font-lock-variable-name-face
     "$" @php-variable-sigil)

   :language 'php
   :feature 'comment
   `(((comment) @font-lock-doc-face
      (:match ,(rx bos "/**")
              @font-lock-doc-face))
     (comment) @font-lock-comment-face)

   :language 'php
   :feature 'string
   `([(string)
      (string_value)
      (encapsed_string)
      (heredoc)
      (heredoc_body)
      (nowdoc_body)
      ]
     @font-lock-string-face)

   :language 'php
   :feature 'interpolation
   `((interpolation "${" @font-lock-misc-punctuation-face)
     (interpolation "}" @font-lock-misc-punctuation-face))

   :language 'php
   :feature 'operator
   `([,@php-ts-mode--operators] @font-lock-operator-face)

   :language 'php
   :feature 'string
   `((string) @font-lock-string-face)

   :language 'php
   :feature 'keyword
   `([,@php-ts-mode--keywords] @font-lock-keyword-face))
  "Tree-sitter font-lock settings for `php-ts-mode'.")

  (defun php-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."
  (pcase (treesit-node-type node)
    ((or "class_declaration"
         "enum_declaration"
         "interface_declaration"
         "method_declaration"
         "namespace_definition")
     (treesit-node-text
      (treesit-node-child-by-field-name node "name")
      t))))

;;;###autoload
(define-derived-mode php-ts-mode prog-mode "PHP"
  "Major mode for editing PHP files, powered by tree-sitter."
  :group 'php
  :syntax-table php-ts-mode--syntax-table

  (unless (treesit-ready-p 'php)
    (error "Tree-sitter for PHP isn't available"))

  (treesit-parser-create 'php)

  ;; Comments.
  (c-ts-common-comment-setup)
  (setq-local comment-start-skip
              (eval-when-compile
                (rx (group (or (: "#" (not (any "[")))
                               (: "/" (+ "/"))
                               (: "/*")))
                    (* (syntax whitespace)))))

  ;; Indent.
  (setq-local c-ts-common-indent-type-regexp-alist
              (eval-when-compile
                `((block . ,(rx (or "class_body"
                                    "array_initializer"
                                    "constructor_body"
                                    "annotation_type_body"
                                    "interface_body"
                                    "lambda_expression"
                                    "enum_body"
                                    "switch_block"
                                    "record_declaration_body"
                                    "block")))
                  (close-bracket . "}")
                  (if . "if_statement")
                  (else . ("if_statement" . "alternative"))
                  (for . "for_statement")
                  (while . "while_statement")
                  (do . "do_statement"))))
  (setq-local c-ts-common-indent-offset 'php-ts-mode-indent-offset)
  (setq-local treesit-simple-indent-rules php-ts-mode--indent-rules)
  (setq-local electric-indent-chars
              (append "{}():;," electric-indent-chars))

  (setq-local treesit-defun-name-function #'php-ts-mode--defun-name)

  ;; Font-lock.
  (setq-local treesit-font-lock-settings php-ts-mode--font-lock-settings)
  (setq-local treesit-font-lock-feature-list
              '((comment definition preprocessor)
                (constant keyword string type variables)
                (annotation expression literal function)
                (bracket delimiter operator)))

  ;; Imenu.
  (setq-local treesit-simple-imenu-settings
              '(("Namespace" "\\`namespace_definition\\'" nil nil)
                ("Enum" "\\`enum_declaration\\'" nil nil)
                ("Class" "\\`class_declaration\\'" nil nil)
                ("Interface" "\\`interface_declaration\\'" nil nil)
                ("Method" "\\`method_declaration\\'" nil nil)))

  (treesit-major-mode-setup))

(when (treesit-ready-p 'php)
  (add-to-list 'auto-mode-alist '("\\.php[s345]?\\'" . php-ts-mode)))

(provide 'php-ts-mode)
;;; php-ts-mode.el ends here