lisp/options.el

   1 ;;; options.el --- edit Options command for Emacs.
   2
   3 ;; Copyright (C) 1985 Free Software Foundation, Inc.
   4
   5 ;; Maintainer: FSF
   6
   7 ;; This file is part of GNU Emacs.
   8
   9 ;; GNU Emacs is free software; you can redistribute it and/or modify
  10 ;; it under the terms of the GNU General Public License as published by
  11 ;; the Free Software Foundation; either version 2, or (at your option)
  12 ;; any later version.
  13
  14 ;; GNU Emacs is distributed in the hope that it will be useful,
  15 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  16 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17 ;; GNU General Public License for more details.
  18
  19 ;; You should have received a copy of the GNU General Public License
  20 ;; along with GNU Emacs; see the file COPYING.  If not, write to the
  21 ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  22 ;; Boston, MA 02111-1307, USA.
  23
  24 ;;; Commentary:
  25
  26 ;; This code provides functions to list and edit the values of all global
  27 ;; option variables known to loaded Emacs Lisp code.  There are two entry
  28 ;; points, `list-options' and `edit' options'.  The latter enters a major
  29 ;; mode specifically for editing option values.  Do `M-x describe-mode' in
  30 ;; that context for more details.
  31
  32 ;; The customization buffer feature is intended to make this obsolete.
  33
  34 ;;; Code:
  35
  36 ;;;###autoload
  37 (defun list-options ()
  38   "Display a list of Emacs user options, with values and documentation.
  39 It is now better to use Customize instead."
  40   (interactive)
  41   (with-output-to-temp-buffer "*List Options*"
  42     (let (vars)
  43       (mapatoms (function (lambda (sym)
  44                             (if (user-variable-p sym)
  45                                 (setq vars (cons sym vars))))))
  46       (setq vars (sort vars 'string-lessp))
  47       (while vars
  48         (let ((sym (car vars)))
  49           (when (boundp sym)
  50             (princ ";; ")
  51             (prin1 sym)
  52             (princ ":\n\t")
  53             (prin1 (symbol-value sym))
  54             (terpri)
  55             (princ (substitute-command-keys
  56                     (documentation-property sym 'variable-documentation)))
  57             (princ "\n;;\n"))
  58           (setq vars (cdr vars))))
  59       (with-current-buffer "*List Options*"
  60         (Edit-options-mode)
  61         (setq buffer-read-only t)))))
  62
  63 ;;;###autoload
  64 (defun edit-options ()
  65   "Edit a list of Emacs user option values.
  66 Selects a buffer containing such a list,
  67 in which there are commands to set the option values.
  68 Type \\[describe-mode] in that buffer for a list of commands.
  69
  70 The Custom feature is intended to make this obsolete."
  71   (interactive)
  72   (list-options)
  73   (pop-to-buffer "*List Options*"))
  74
  75 (defvar Edit-options-mode-map
  76   (let ((map (make-keymap)))
  77     (define-key map "s" 'Edit-options-set)
  78     (define-key map "x" 'Edit-options-toggle)
  79     (define-key map "1" 'Edit-options-t)
  80     (define-key map "0" 'Edit-options-nil)
  81     (define-key map "p" 'backward-paragraph)
  82     (define-key map " " 'forward-paragraph)
  83     (define-key map "n" 'forward-paragraph)
  84     map)
  85   "")
  86
  87 ;; Edit Options mode is suitable only for specially formatted data.
  88 (put 'Edit-options-mode 'mode-class 'special)
  89
  90 (defun Edit-options-mode ()
  91   "\\<Edit-options-mode-map>\
  92 Major mode for editing Emacs user option settings.
  93 Special commands are:
  94 \\[Edit-options-set] -- set variable point points at.  New value read using minibuffer.
  95 \\[Edit-options-toggle] -- toggle variable, t -> nil, nil -> t.
  96 \\[Edit-options-t] -- set variable to t.
  97 \\[Edit-options-nil] -- set variable to nil.
  98 Changed values made by these commands take effect immediately.
  99
 100 Each variable description is a paragraph.
 101 For convenience, the characters \\[backward-paragraph] and \\[forward-paragraph] move back and forward by paragraphs."
 102   (kill-all-local-variables)
 103   (set-syntax-table emacs-lisp-mode-syntax-table)
 104   (use-local-map Edit-options-mode-map)
 105   (make-local-variable 'paragraph-separate)
 106   (setq paragraph-separate "[^\^@-\^?]")
 107   (make-local-variable 'paragraph-start)
 108   (setq paragraph-start "\t")
 109   (setq truncate-lines t)
 110   (setq major-mode 'Edit-options-mode)
 111   (setq mode-name "Options")
 112   (run-hooks 'Edit-options-mode-hook))
 113
 114 (defun Edit-options-set () (interactive)
 115   (Edit-options-modify
 116    (lambda (var) (eval-minibuffer (concat "New " (symbol-name var) ": ")))))
 117
 118 (defun Edit-options-toggle () (interactive)
 119   (Edit-options-modify (lambda (var) (not (symbol-value var)))))
 120
 121 (defun Edit-options-t () (interactive)
 122   (Edit-options-modify (lambda (var) t)))
 123
 124 (defun Edit-options-nil () (interactive)
 125   (Edit-options-modify (lambda (var) nil)))
 126
 127 (defun Edit-options-modify (modfun)
 128   (save-excursion
 129    (let ((buffer-read-only nil) var pos)
 130      (re-search-backward "^;; \\|\\`")
 131      (forward-char 3)
 132      (setq pos (point))
 133      (save-restriction
 134        (narrow-to-region pos (progn (end-of-line) (1- (point))))
 135        (goto-char pos)
 136        (setq var (read (current-buffer))))
 137      (goto-char pos)
 138      (forward-line 1)
 139      (forward-char 1)
 140      (save-excursion
 141        (set var (funcall modfun var)))
 142      (kill-sexp 1)
 143      (prin1 (symbol-value var) (current-buffer)))))
 144
 145 (provide 'options)
 146
 147 ;;; options.el ends here