1;;; options.el --- edit Options command for Emacs
2
3;; Copyright (C) 1985, 2001, 2002, 2003, 2004, 2005,
4;;   2006, 2007 Free Software Foundation, Inc.
5
6;; Maintainer: FSF
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 2, or (at your option)
13;; 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; see the file COPYING.  If not, write to the
22;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
23;; Boston, MA 02110-1301, USA.
24
25;;; Commentary:
26
27;; This code provides functions to list and edit the values of all global
28;; option variables known to loaded Emacs Lisp code.  There are two entry
29;; points, `list-options' and `edit' options'.  The latter enters a major
30;; mode specifically for editing option values.  Do `M-x describe-mode' in
31;; that context for more details.
32
33;; The customization buffer feature is intended to make this obsolete.
34
35;;; Code:
36
37;;;###autoload
38(defun list-options ()
39  "Display a list of Emacs user options, with values and documentation.
40It is now better to use Customize instead."
41  (interactive)
42  (with-output-to-temp-buffer "*List Options*"
43    (let (vars)
44      (princ "This facility is obsolete; we recommend using M-x customize instead.")
45
46      (mapatoms (function (lambda (sym)
47			    (if (user-variable-p sym)
48				(setq vars (cons sym vars))))))
49      (setq vars (sort vars 'string-lessp))
50      (while vars
51	(let ((sym (car vars)))
52	  (when (boundp sym)
53	    (princ ";; ")
54	    (prin1 sym)
55	    (princ ":\n\t")
56	    (prin1 (symbol-value sym))
57	    (terpri)
58	    (princ (substitute-command-keys
59		    (documentation-property sym 'variable-documentation)))
60	    (princ "\n;;\n"))
61	  (setq vars (cdr vars))))
62      (with-current-buffer "*List Options*"
63	(Edit-options-mode)
64	(setq buffer-read-only t)))))
65
66;;;###autoload
67(defun edit-options ()
68  "Edit a list of Emacs user option values.
69Selects a buffer containing such a list,
70in which there are commands to set the option values.
71Type \\[describe-mode] in that buffer for a list of commands.
72
73The Custom feature is intended to make this obsolete."
74  (interactive)
75  (list-options)
76  (pop-to-buffer "*List Options*"))
77
78(defvar Edit-options-mode-map
79  (let ((map (make-keymap)))
80    (define-key map "s" 'Edit-options-set)
81    (define-key map "x" 'Edit-options-toggle)
82    (define-key map "1" 'Edit-options-t)
83    (define-key map "0" 'Edit-options-nil)
84    (define-key map "p" 'backward-paragraph)
85    (define-key map " " 'forward-paragraph)
86    (define-key map "n" 'forward-paragraph)
87    map)
88  "")
89
90;; Edit Options mode is suitable only for specially formatted data.
91(put 'Edit-options-mode 'mode-class 'special)
92
93(defun Edit-options-mode ()
94  "\\<Edit-options-mode-map>\
95Major mode for editing Emacs user option settings.
96Special commands are:
97\\[Edit-options-set] -- set variable point points at.  New value read using minibuffer.
98\\[Edit-options-toggle] -- toggle variable, t -> nil, nil -> t.
99\\[Edit-options-t] -- set variable to t.
100\\[Edit-options-nil] -- set variable to nil.
101Changed values made by these commands take effect immediately.
102
103Each variable description is a paragraph.
104For convenience, the characters \\[backward-paragraph] and \\[forward-paragraph] move back and forward by paragraphs."
105  (kill-all-local-variables)
106  (set-syntax-table emacs-lisp-mode-syntax-table)
107  (use-local-map Edit-options-mode-map)
108  (make-local-variable 'paragraph-separate)
109  (setq paragraph-separate "[^\^@-\^?]")
110  (make-local-variable 'paragraph-start)
111  (setq paragraph-start "\t")
112  (setq truncate-lines t)
113  (setq major-mode 'Edit-options-mode)
114  (setq mode-name "Options")
115  (run-mode-hooks 'Edit-options-mode-hook))
116
117(defun Edit-options-set () (interactive)
118  (Edit-options-modify
119   (lambda (var) (eval-minibuffer (concat "New " (symbol-name var) ": ")))))
120
121(defun Edit-options-toggle () (interactive)
122  (Edit-options-modify (lambda (var) (not (symbol-value var)))))
123
124(defun Edit-options-t () (interactive)
125  (Edit-options-modify (lambda (var) t)))
126
127(defun Edit-options-nil () (interactive)
128  (Edit-options-modify (lambda (var) nil)))
129
130(defun Edit-options-modify (modfun)
131  (save-excursion
132   (let ((buffer-read-only nil) var pos)
133     (re-search-backward "^;; \\|\\`")
134     (forward-char 3)
135     (setq pos (point))
136     (save-restriction
137       (narrow-to-region pos (progn (end-of-line) (1- (point))))
138       (goto-char pos)
139       (setq var (read (current-buffer))))
140     (goto-char pos)
141     (forward-line 1)
142     (forward-char 1)
143     (save-excursion
144       (set var (funcall modfun var)))
145     (kill-sexp 1)
146     (prin1 (symbol-value var) (current-buffer)))))
147
148(provide 'options)
149
150;;; arch-tag: d18211a1-f3fb-48c9-a449-d5acde406a3c
151;;; options.el ends here
152