;;; m4-mode.el --- m4 code editing commands for Emacs -*- lexical-binding:t -*-
;; Copyright (C) 1996-1997, 2001-2021 Free Software Foundation, Inc.
;; Author: Andrew Csillag <drew@thecsillags.com>
;; Keywords: languages, faces
;; 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:
;; A smart editing mode for m4 macro definitions. It seems to have most of the
;; syntax right (sexp motion commands work, but function motion commands don't).
;; It also sets the font-lock syntax stuff for colorization
;; To Do's:
;; * want to make m4-m4-(buffer|region) look sorta like M-x compile look&feel ?
;; * sexp motion commands don't seem to work right
;;; Thanks:
;;; to Akim Demaille and Terry Jones for the bug reports
;;; to Simon Marshall for the regexp tip
;;; to Martin Buchholz for some general fixes
;;; Code:
(defgroup m4 nil
"m4 code editing commands for Emacs."
:link '(custom-group-link :tag "Font Lock Faces group" font-lock-faces)
:prefix "m4-"
:group 'languages)
(defcustom m4-program "m4"
"File name of the m4 executable.
If m4 is not in your PATH, set this to an absolute file name."
:version "24.4"
:type 'file)
;;options to m4
(defcustom m4-program-options nil
"Options to pass to `m4-program'."
:type '(repeat string))
;;to use --prefix-builtins, you can use
;;(defconst m4-program-options '("-P"))
;;or
;;(defconst m4-program-options '("--prefix-builtins"))
;; Needed at compile-time for `m4-font-lock-keywords' below.
(eval-and-compile
(defconst m4--macro-list
;; From (info "(m4) Macro index")
'("__file__" "__gnu__" "__line__" "__os2__" "__program__" "__unix__"
"__windows__" "argn" "array" "array_set" "builtin" "capitalize"
"changecom" "changequote" "changeword" "cleardivert" "cond" "copy"
"curry" "debugfile" "debugmode" "decr" "define" "define_blind"
"defn" "divert" "divnum" "dnl" "downcase" "dquote" "dquote_elt"
"dumpdef" "errprint" "esyscmd" "eval" "example" "exch"
"fatal_error" "file" "foreach" "foreachq" "forloop" "format" "gnu"
"ifdef" "ifelse" "include" "incr" "index" "indir" "join" "joinall"
"len" "line" "m4exit" "m4wrap" "maketemp" "mkstemp" "nargs" "os2"
"patsubst" "popdef" "pushdef" "quote" "regexp" "rename" "reverse"
"shift" "sinclude" "stack_foreach" "stack_foreach_lifo"
"stack_foreach_sep" "stack_foreach_sep_lifo" "substr" "syscmd"
"sysval" "traceoff" "traceon" "translit" "undefine" "undivert"
"unix" "upcase" "windows")
"List of valid m4 macros for M4 mode."))
(defvar m4-font-lock-keywords
(eval-when-compile
`(("\\(\\_<\\(m4_\\)?dnl\\_>\\).*$" (0 font-lock-comment-face t))
("\\$[*#@0-9]" . font-lock-variable-name-face)
("\\$@" . font-lock-variable-name-face)
("\\$\\*" . font-lock-variable-name-face)
(,(concat "\\_<\\(m4_\\)?" (regexp-opt m4--macro-list) "\\_>")
. font-lock-keyword-face)))
"Default `font-lock-keywords' for M4 mode.")
(defcustom m4-mode-hook nil
"Hook called by `m4-mode'."
:type 'hook)
;;this may still need some work
(defvar m4-mode-syntax-table
(let ((table (make-syntax-table)))
(modify-syntax-entry ?` "('" table)
(modify-syntax-entry ?' ")`" table)
(modify-syntax-entry ?# "<\n" table)
(modify-syntax-entry ?\n ">#" table)
(modify-syntax-entry ?{ "." table)
(modify-syntax-entry ?} "." table)
(modify-syntax-entry ?_ "_" table)
(modify-syntax-entry ?* "." table)
(modify-syntax-entry ?\" "." table)
table)
"Syntax table used while in `m4-mode'.")
(defun m4--quoted-p (pos)
"Return non-nil if POS is inside a quoted string."
(let ((quoted nil))
(dolist (o (nth 9 (save-excursion (syntax-ppss pos))))
(if (eq (char-after o) ?\`) (setq quoted t)))
quoted))
(defconst m4-syntax-propertize
(syntax-propertize-rules
("#" (0 (when (m4--quoted-p (match-beginning 0))
(string-to-syntax "."))))))
(defvar m4-mode-map
(let ((map (make-sparse-keymap)))
(define-key map "\C-c\C-b" 'm4-m4-buffer)
(define-key map "\C-c\C-r" 'm4-m4-region)
(define-key map "\C-c\C-c" 'comment-region)
map)
"Keymap for M4 Mode.")
(easy-menu-define m4-mode-menu m4-mode-map
"Menu for M4 Mode."
'("M4"
["M4 Region" m4-m4-region
:help "Send contents of the current region to m4"]
["M4 Buffer" m4-m4-buffer
:help "Send contents of the current buffer to m4"]
["Comment Region" comment-region
:help "Comment Region"]))
(defun m4-m4-buffer ()
"Send contents of the current buffer to m4."
(interactive)
(shell-command-on-region
(point-min) (point-max)
(mapconcat #'identity (cons m4-program m4-program-options) "\s")
"*m4-output*" nil)
(switch-to-buffer-other-window "*m4-output*"))
(defun m4-m4-region ()
"Send contents of the current region to m4."
(interactive)
(shell-command-on-region
(point) (mark)
(mapconcat #'identity (cons m4-program m4-program-options) "\s")
"*m4-output*" nil)
(switch-to-buffer-other-window "*m4-output*"))
(defun m4-current-defun-name ()
"Return the name of the M4 function at point, or nil."
(save-excursion
(if (re-search-backward
"^\\(\\(m4_\\)?define\\|A._DEFUN\\)(\\[?\\([A-Za-z0-9_]+\\)" nil t)
(match-string-no-properties 3))))
;;;###autoload
(define-derived-mode m4-mode prog-mode "m4"
"A major mode to edit m4 macro files."
(setq-local comment-start "#")
(setq-local parse-sexp-ignore-comments t)
(setq-local add-log-current-defun-function #'m4-current-defun-name)
(setq-local syntax-propertize-function m4-syntax-propertize)
(setq-local font-lock-defaults '(m4-font-lock-keywords nil)))
(provide 'm4-mode)
;;stuff to play with for debugging
;(char-to-string (char-syntax ?`))
;;; m4-mode.el ends here