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Diffstat (limited to 'lisp/progmodes/c-ts-common.el')
| -rw-r--r-- | lisp/progmodes/c-ts-common.el | 247 |
1 files changed, 247 insertions, 0 deletions
diff --git a/lisp/progmodes/c-ts-common.el b/lisp/progmodes/c-ts-common.el new file mode 100644 index 00000000000..6671d4be5b6 --- /dev/null +++ b/lisp/progmodes/c-ts-common.el @@ -0,0 +1,247 @@ +;;; c-ts-common.el --- Utilities for C like Languages -*- lexical-binding: t; -*- + +;; Copyright (C) 2023 Free Software Foundation, Inc. + +;; Author : 付禹安 (Yuan Fu) <casouri@gmail.com> +;; Keywords : c c++ java javascript rust 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: +;; +;; For C-like language major modes: +;; +;; - Use `c-ts-common-comment-setup' to setup comment variables and +;; filling. +;; +;; - Use simple-indent matcher `c-ts-common-looking-at-star' and +;; anchor `c-ts-common-comment-start-after-first-star' for indenting +;; block comments. See `c-ts-mode--indent-styles' for example. + +;;; Code: + +(require 'treesit) +(eval-when-compile (require 'rx)) + +(declare-function treesit-node-start "treesit.c") +(declare-function treesit-node-end "treesit.c") +(declare-function treesit-node-type "treesit.c") + +(defun c-ts-common-looking-at-star (_n _p bol &rest _) + "A tree-sitter simple indent matcher. +Matches if there is a \"*\" after BOL." + (eq (char-after bol) ?*)) + +(defun c-ts-common-comment-start-after-first-star (_n parent &rest _) + "A tree-sitter simple indent anchor. +Finds the \"/*\" and returns the point after the \"*\". +Assumes PARENT is a comment node." + (save-excursion + (goto-char (treesit-node-start parent)) + (if (looking-at (rx "/*")) + (match-end 0) + (point)))) + +(defun c-ts-common-comment-2nd-line-matcher (_n parent &rest _) + "Matches if point is at the second line of a block comment. +PARENT should be a comment node." + (and (equal (treesit-node-type parent) "comment") + (save-excursion + (forward-line -1) + (back-to-indentation) + (eq (point) (treesit-node-start parent))))) + +(defun c-ts-common-comment-2nd-line-anchor (_n _p bol &rest _) + "Return appropriate anchor for the second line of a comment. + +If the first line is /* alone, return the position right after +the star; if the first line is /* followed by some text, return +the position right before the text minus 1. + +Use an offset of 1 with this anchor. BOL is the beginning of +non-whitespace characters of the current line." + (save-excursion + (forward-line -1) + (back-to-indentation) + (when (looking-at comment-start-skip) + (goto-char (match-end 0)) + (if (looking-at (rx (* (or " " "\t")) eol)) + ;; Only /* at the first line. + (progn (skip-chars-backward " \t") + (if (save-excursion + (goto-char bol) + (looking-at (rx "*"))) + ;; The common case. Checked by "Multiline Block + ;; Comments 4". + (point) + ;; The "Multiline Block Comments 2" test in + ;; c-ts-common-resources/indent.erts checks this. + (1- (point)))) + ;; There is something after /* at the first line. The + ;; "Multiline Block Comments 3" test checks this. + (1- (point)))))) + +(defvar c-ts-common--comment-regexp + ;; These covers C/C++, Java, JavaScript, TypeScript, Rust, C#. + (rx (or "comment" "line_comment" "block_comment")) + "Regexp pattern that matches a comment in C-like languages.") + +(defun c-ts-common--fill-paragraph (&optional arg) + "Fillling function for `c-ts-common'. +ARG is passed to `fill-paragraph'." + (interactive "*P") + (save-restriction + (widen) + (let ((node (treesit-node-at (point)))) + (when (string-match-p c-ts-common--comment-regexp + (treesit-node-type node)) + (if (save-excursion + (goto-char (treesit-node-start node)) + (looking-at "//")) + (fill-comment-paragraph arg) + (c-ts-common--fill-block-comment arg))) + ;; Return t so `fill-paragraph' doesn't attempt to fill by + ;; itself. + t))) + +(defun c-ts-common--fill-block-comment (&optional arg) + "Fillling function for block comments. +ARG is passed to `fill-paragraph'. Assume point is in a block +comment." + (let* ((node (treesit-node-at (point))) + (start (treesit-node-start node)) + (end (treesit-node-end node)) + ;; Bind to nil to avoid infinite recursion. + (fill-paragraph-function nil) + (orig-point (point-marker)) + (start-marker (point-marker)) + (end-marker nil) + (end-len 0)) + (move-marker start-marker start) + ;; We mask "/*" and the space before "*/" like + ;; `c-fill-paragraph' does. + (atomic-change-group + ;; Mask "/*". + (goto-char start) + (when (looking-at (rx (* (syntax whitespace)) + (group "/") "*")) + (goto-char (match-beginning 1)) + (move-marker start-marker (point)) + (replace-match " " nil nil nil 1)) + ;; Include whitespaces before /*. + (goto-char start) + (beginning-of-line) + (setq start (point)) + ;; Mask spaces before "*/" if it is attached at the end + ;; of a sentence rather than on its own line. + (goto-char end) + (when (looking-back (rx (not (syntax whitespace)) + (group (+ (syntax whitespace))) + "*/") + (line-beginning-position)) + (goto-char (match-beginning 1)) + (setq end-marker (point-marker)) + (setq end-len (- (match-end 1) (match-beginning 1))) + (replace-match (make-string end-len ?x) + nil nil nil 1)) + ;; If "*/" is on its own line, don't included it in the + ;; filling region. + (when (not end-marker) + (goto-char end) + (when (looking-back (rx "*/") 2) + (backward-char 2) + (skip-syntax-backward "-") + (setq end (point)))) + ;; Let `fill-paragraph' do its thing. + (goto-char orig-point) + (narrow-to-region start end) + ;; We don't want to fill the region between START and + ;; START-MARKER, otherwise the filling function might delete + ;; some spaces there. + (fill-region start-marker end arg) + ;; Unmask. + (when start-marker + (goto-char start-marker) + (delete-char 1) + (insert "/")) + (when end-marker + (goto-char end-marker) + (delete-region (point) (+ end-len (point))) + (insert (make-string end-len ?\s)))))) + +(defun c-ts-common-comment-setup () + "Set up local variables for C-like comment. + +Set up: + - `comment-start' + - `comment-end' + - `comment-start-skip' + - `comment-end-skip' + - `adaptive-fill-mode' + - `adaptive-fill-first-line-regexp' + - `paragraph-start' + - `paragraph-separate' + - `fill-paragraph-function'" + (setq-local comment-start "// ") + (setq-local comment-end "") + (setq-local comment-start-skip (rx (or (seq "/" (+ "/")) + (seq "/" (+ "*"))) + (* (syntax whitespace)))) + (setq-local comment-end-skip + (rx (* (syntax whitespace)) + (group (or (syntax comment-end) + (seq (+ "*") "/"))))) + (setq-local adaptive-fill-mode t) + ;; This matches (1) empty spaces (the default), (2) "//", (3) "*", + ;; but do not match "/*", because we don't want to use "/*" as + ;; prefix when filling. (Actually, it doesn't matter, because + ;; `comment-start-skip' matches "/*" which will cause + ;; `fill-context-prefix' to use "/*" as a prefix for filling, that's + ;; why we mask the "/*" in `c-ts-common--fill-paragraph'.) + (setq-local adaptive-fill-regexp + (concat (rx (* (syntax whitespace)) + (group (or (seq "/" (+ "/")) (* "*")))) + adaptive-fill-regexp)) + ;; Note the missing * comparing to `adaptive-fill-regexp'. The + ;; reason for its absence is a bit convoluted to explain. Suffice + ;; to say that without it, filling a single line paragraph that + ;; starts with /* doesn't insert * at the beginning of each + ;; following line, and filling a multi-line paragraph whose first + ;; two lines start with * does insert * at the beginning of each + ;; following line. If you know how does adaptive filling works, you + ;; know what I mean. + (setq-local adaptive-fill-first-line-regexp + (rx bos + (seq (* (syntax whitespace)) + (group (seq "/" (+ "/"))) + (* (syntax whitespace))) + eos)) + ;; Same as `adaptive-fill-regexp'. + (setq-local paragraph-start + (rx (or (seq (* (syntax whitespace)) + (group (or (seq "/" (+ "/")) (* "*"))) + (* (syntax whitespace)) + ;; Add this eol so that in + ;; `fill-context-prefix', `paragraph-start' + ;; doesn't match the prefix. + eol) + "\f"))) + (setq-local paragraph-separate paragraph-start) + (setq-local fill-paragraph-function #'c-ts-common--fill-paragraph)) + +(provide 'c-ts-common) + +;;; c-ts-common.el ends here |