1;;; autoconf.el --- mode for editing Autoconf configure.ac files  -*- lexical-binding: t; -*-
2
3;; Copyright (C) 2000-2021 Free Software Foundation, Inc.
4
5;; Author: Dave Love <fx@gnu.org>
6;; Keywords: languages
7
8;; This file is part of GNU Emacs.
9
10;; GNU Emacs is free software: you can redistribute it and/or modify
11;; it under the terms of the GNU General Public License as published by
12;; the Free Software Foundation, either version 3 of the License, or
13;; (at your option) any later version.
14
15;; GNU Emacs is distributed in the hope that it will be useful,
16;; but WITHOUT ANY WARRANTY; without even the implied warranty of
17;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
18;; GNU General Public License for more details.
19
20;; You should have received a copy of the GNU General Public License
21;; along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.
22
23;;; Commentary:
24
25;; Provides fairly minimal font-lock, imenu and indentation support
26;; for editing configure.ac files.  Only Autoconf syntax is processed.
27;; There is no attempt to deal with shell text -- probably that will
28;; always lose.
29
30;; This is specialized for configure.ac files.  It doesn't inherit the
31;; general M4 stuff from M4 mode.
32
33;; There is also an autoconf-mode.el in existence.  That appears to be
34;; for editing the Autoconf M4 source, rather than configure.ac files.
35
36;;; Code:
37
38(defvar autoconf-mode-map (make-sparse-keymap))
39
40(defvar autoconf-mode-hook nil
41  "Hook run by `autoconf-mode'.")
42
43(defconst autoconf-definition-regexp
44  "A\\(?:H_TEMPLATE\\|C_\\(?:SUBST\\|DEFINE\\(?:_UNQUOTED\\)?\\)\\)(\\[*\\(\\(?:\\sw\\|\\s_\\)+\\)\\]*")
45
46(defvar autoconf-font-lock-keywords
47  `(("\\_<\\(?:A[CHMS]\\|LT\\)_\\(?:\\sw\\|\\s_\\)+" . font-lock-keyword-face)
48    (,autoconf-definition-regexp
49     1 font-lock-function-name-face)
50    ;; Are any other M4 keywords really appropriate for configure.ac,
51    ;; given that we do `dnl'?
52    ("changequote" . font-lock-keyword-face)))
53
54(defvar autoconf-mode-syntax-table
55  (let ((table (make-syntax-table)))
56    (modify-syntax-entry ?\" "." table)
57    (modify-syntax-entry ?\n ">" table)
58    (modify-syntax-entry ?# "<" table)
59    table))
60
61(defvar autoconf-imenu-generic-expression
62  (list (list nil autoconf-definition-regexp 1)))
63
64;; It's not clear how best to implement this.
65(defun autoconf-current-defun-function ()
66  "Function to use for `add-log-current-defun-function' in Autoconf mode.
67This version looks back for an AC_DEFINE or AC_SUBST.  It will stop
68searching backwards at another AC_... command."
69  (save-excursion
70    (skip-syntax-forward "w_" (line-end-position))
71    (if (re-search-backward autoconf-definition-regexp
72                            (save-excursion (beginning-of-defun) (point))
73                            t)
74        (match-string-no-properties 1))))
75
76;;;###autoload
77(define-derived-mode autoconf-mode prog-mode "Autoconf"
78  "Major mode for editing Autoconf configure.ac files."
79  (setq-local parens-require-spaces nil) ; for M4 arg lists
80  (setq-local defun-prompt-regexp "^[ \t]*A[CM]_\\(\\sw\\|\\s_\\)+")
81  (setq-local comment-start "dnl ")
82  ;; We want to avoid matching "dnl" in other text.
83  (setq-local comment-start-skip "\\(?:\\(\\W\\|^\\)dnl\\|#\\) +")
84  (setq-local syntax-propertize-function
85	      (syntax-propertize-rules ("\\<dnl\\>" (0 "<"))))
86  (setq-local font-lock-defaults
87	      '(autoconf-font-lock-keywords nil nil))
88  (setq-local imenu-generic-expression autoconf-imenu-generic-expression)
89  (setq-local indent-line-function #'indent-relative)
90  (setq-local add-log-current-defun-function
91	      #'autoconf-current-defun-function))
92
93(provide 'autoconf-mode)
94(provide 'autoconf)
95
96;;; autoconf.el ends here
97