lisp/obsolete/options.el

   1 ;;; options.el --- edit Options command for Emacs
   2
   3 ;; Copyright (C) 1985, 2001-2017 Free Software Foundation, Inc.
   4
   5 ;; Maintainer: emacs-devel@gnu.org
   6 ;; Obsolete-since: 22.1
   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 <http://www.gnu.org/licenses/>.
  22
  23 ;;; Commentary:
  24
  25 ;; This code provides functions to list and edit the values of all global
  26 ;; option variables known to loaded Emacs Lisp code.  There are two entry
  27 ;; points, `list-options' and `edit' options'.  The latter enters a major
  28 ;; mode specifically for editing option values.  Do `M-x describe-mode' in
  29 ;; that context for more details.
  30
  31 ;; The customization buffer feature is intended to make this obsolete.
  32
  33 ;;; Code:
  34
  35 ;;;###autoload
  36 (defun list-options ()
  37   "Display a list of Emacs user options, with values and documentation.
  38 It is now better to use Customize instead."
  39   (interactive)
  40   (with-output-to-temp-buffer "*List Options*"
  41     (let (vars)
  42       (princ "This facility is obsolete; we recommend using M-x customize instead.")
  43
  44       (mapatoms (function (lambda (sym)
  45                             (if (custom-variable-p sym)
  46                                 (setq vars (cons sym vars))))))
  47       (setq vars (sort vars 'string-lessp))
  48       (while vars
  49         (let ((sym (car vars)))
  50           (when (boundp sym)
  51             (princ ";; ")
  52             (prin1 sym)
  53             (princ ":\n\t")
  54             (prin1 (symbol-value sym))
  55             (terpri)
  56             (princ (substitute-command-keys
  57                     (documentation-property sym 'variable-documentation)))
  58             (princ "\n;;\n"))
  59           (setq vars (cdr vars))))
  60       (with-current-buffer "*List Options*"
  61         (Edit-options-mode)
  62         (setq buffer-read-only t)))))
  63
  64 ;;;###autoload
  65 (defun edit-options ()
  66   "Edit a list of Emacs user option values.
  67 Selects a buffer containing such a list,
  68 in which there are commands to set the option values.
  69 Type \\[describe-mode] in that buffer for a list of commands.
  70
  71 The Custom feature is intended to make this obsolete."
  72   (interactive)
  73   (list-options)
  74   (pop-to-buffer "*List Options*"))
  75
  76 (defvar Edit-options-mode-map
  77   (let ((map (make-keymap)))
  78     (define-key map "s" 'Edit-options-set)
  79     (define-key map "x" 'Edit-options-toggle)
  80     (define-key map "1" 'Edit-options-t)
  81     (define-key map "0" 'Edit-options-nil)
  82     (define-key map "p" 'backward-paragraph)
  83     (define-key map " " 'forward-paragraph)
  84     (define-key map "n" 'forward-paragraph)
  85     map)
  86   "")
  87
  88 ;; Edit Options mode is suitable only for specially formatted data.
  89 (put 'Edit-options-mode 'mode-class 'special)
  90
  91 (define-derived-mode Edit-options-mode emacs-lisp-mode "Options"
  92   "\\<Edit-options-mode-map>\
  93 Major mode for editing Emacs user option settings.
  94 Special commands are:
  95 \\[Edit-options-set] -- set variable point points at.  New value read using minibuffer.
  96 \\[Edit-options-toggle] -- toggle variable, t -> nil, nil -> t.
  97 \\[Edit-options-t] -- set variable to t.
  98 \\[Edit-options-nil] -- set variable to nil.
  99 Changed values made by these commands take effect immediately.
 100
 101 Each variable description is a paragraph.
 102 For convenience, the characters \\[backward-paragraph] and \\[forward-paragraph] move back and forward by paragraphs."
 103   (setq-local paragraph-separate "[^\^@-\^?]")
 104   (setq-local paragraph-start "\t")
 105   (setq-local truncate-lines t))
 106
 107 (defun Edit-options-set () (interactive)
 108   (Edit-options-modify
 109    (lambda (var) (eval-minibuffer (concat "New " (symbol-name var) ": ")))))
 110
 111 (defun Edit-options-toggle () (interactive)
 112   (Edit-options-modify (lambda (var) (not (symbol-value var)))))
 113
 114 (defun Edit-options-t () (interactive)
 115   (Edit-options-modify (lambda (var) t)))
 116
 117 (defun Edit-options-nil () (interactive)
 118   (Edit-options-modify (lambda (var) nil)))
 119
 120 (defun Edit-options-modify (modfun)
 121   (save-excursion
 122    (let ((buffer-read-only nil) var pos)
 123      (re-search-backward "^;; \\|\\`")
 124      (forward-char 3)
 125      (setq pos (point))
 126      (save-restriction
 127        (narrow-to-region pos (progn (end-of-line) (1- (point))))
 128        (goto-char pos)
 129        (setq var (read (current-buffer))))
 130      (goto-char pos)
 131      (forward-line 1)
 132      (forward-char 1)
 133      (save-excursion
 134        (set var (funcall modfun var)))
 135      (kill-sexp 1)
 136      (prin1 (symbol-value var) (current-buffer)))))
 137
 138 (provide 'options)
 139
 140 ;;; options.el ends here