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|
;;; autoconf.el --- mode for editing Autoconf configure.ac files -*- lexical-binding: t; -*-
;; Copyright (C) 2000-2025 Free Software Foundation, Inc.
;; Author: Dave Love <fx@gnu.org>
;; Keywords: languages
;; 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:
;; Provides fairly minimal font-lock, imenu and indentation support
;; for editing configure.ac files. Only Autoconf syntax is processed.
;; There is no attempt to deal with shell text -- probably that will
;; always lose.
;; This is specialized for configure.ac files. It doesn't inherit the
;; general M4 stuff from M4 mode.
;; There is also an autoconf-mode.el in existence. That appears to be
;; for editing the Autoconf M4 source, rather than configure.ac files.
;;; Code:
(defvar-keymap autoconf-mode-map)
(defvar autoconf-mode-hook nil
"Hook run by `autoconf-mode'.")
(rx-define autoconf--symbol (+ (| (syntax word) (syntax symbol))))
;; Any Autoconf macro name.
(rx-define autoconf--macro
(: (| "AC" ;; Autoconf.
"AH" ;; Autoheader.
"AM" ;; Automake.
"AS" ;; M4sh.
"AU" ;; Autoupdate.
"AX" ;; Autoconf Archive.
"LT" ;; Libtool.
"gl") ;; Gnulib.
?_ autoconf--symbol))
(defconst autoconf-definition-regexp
;; Historically this `defconst' defined only group #1.
;; For internal Font Lock use, the presence of an optional group #2
;; identifies a function rather than variable definition.
(rx-let ((argbeg (: ?\( (* ?\[)))
(argend (in "]),"))
(plaindef (: argbeg (group-n 1 autoconf--symbol))))
(rx symbol-start
(| (: "AC_DEFINE"
;; AC_DEFINE and AC_DEFINE_UNQUOTED can define object- and
;; function-like CPP macros. An open-paren is easy to
;; detect in the case of AC_DEFINE. Doing the same for
;; AC_DEFINE_UNQUOTED in the general case requires
;; knowledge of shell syntax, so don't bother for now.
(| (: plaindef (? (group-n 2 ?\()))
(: "_UNQUOTED" argbeg (group-n 1 (+ (not argend))))))
(: (| "AC_SUBST"
"AH_TEMPLATE"
"AH_VERBATIM"
"AM_CONDITIONAL"
"AM_MISSING_PROG"
(group-n 2 (| "AC_DEFUN"
"AC_DEFUN_ONCE"
"AU_ALIAS"
"AU_DEFUN")))
plaindef))))
"Matches Autoconf macro calls that define something.
The thing being defined is captured in the first subexpression group.")
(defvar autoconf-font-lock-keywords
`(,(rx symbol-start autoconf--macro)
(,autoconf-definition-regexp
1 (if (match-beginning 2)
'font-lock-function-name-face
'font-lock-variable-name-face))
;; Are any other M4 keywords really appropriate for configure.ac,
;; given that we do `dnl'?
"\\_<changequote\\_>"))
(defvar autoconf-mode-syntax-table
(let ((table (make-syntax-table)))
(modify-syntax-entry ?\" "." table)
(modify-syntax-entry ?\n ">" table)
(modify-syntax-entry ?# "<" table)
table))
(defvar autoconf-imenu-generic-expression
;; This lists both variable-like and function-like definitions in a
;; flat list, but they could be distinguished if desired.
(list (list nil autoconf-definition-regexp 1)))
;; It's not clear how best to implement this.
(defun autoconf-current-defun-function ()
"Function to use for `add-log-current-defun-function' in Autoconf mode.
This version looks back for a definition such as by AC_DEFINE or
AC_SUBST. It stops searching when it encounters other Autoconf macros."
(save-excursion
(skip-syntax-forward "w_" (pos-eol))
(if (re-search-backward autoconf-definition-regexp
(save-excursion (beginning-of-defun) (point))
t)
(match-string-no-properties 1))))
;;;###autoload
(define-derived-mode autoconf-mode prog-mode "Autoconf"
"Major mode for editing Autoconf configure.ac files."
(setq-local parens-require-spaces nil) ; for M4 arg lists
;; FIXME: Should indented macro calls really count as defuns?
(setq-local defun-prompt-regexp (rx bol (* (in "\t ")) autoconf--macro))
(setq-local open-paren-in-column-0-is-defun-start nil)
(setq-local comment-start "dnl ")
;; We want to avoid matching "dnl" in other text.
(setq-local comment-start-skip "\\(?:\\(\\W\\|^\\)dnl\\|#\\) +")
(setq-local syntax-propertize-function
(syntax-propertize-rules ("\\<dnl\\>" (0 "<"))))
(setq-local font-lock-defaults '(autoconf-font-lock-keywords))
(setq-local imenu-generic-expression autoconf-imenu-generic-expression)
(setq-local indent-line-function #'indent-relative)
(setq-local add-log-current-defun-function
#'autoconf-current-defun-function))
(provide 'autoconf-mode)
(provide 'autoconf)
;;; autoconf.el ends here
|
