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   (interactive)
  40   (with-output-to-temp-buffer "*List Options*"
  41     (let (vars)
  42       (mapatoms (function (lambda (sym)
  43                             (if (user-variable-p sym)
  44                                 (setq vars (cons sym vars))))))
  45       (setq vars (sort vars 'string-lessp))
  46       (while vars
  47         (let ((sym (car vars)))
  48           (when (boundp sym)
  49             (princ ";; ")
  50             (prin1 sym)
  51             (princ ":\n\t")
  52             (prin1 (symbol-value sym))
  53             (terpri)
  54             (princ (substitute-command-keys
  55                     (documentation-property sym 'variable-documentation)))
  56             (princ "\n;;\n"))
  57           (setq vars (cdr vars))))
  58       (with-current-buffer "*List Options*"
  59         (Edit-options-mode)
  60         (setq buffer-read-only t)))))
  61
  62 ;;;###autoload
  63 (defun edit-options ()
  64   "Edit a list of Emacs user option values.
  65 Selects a buffer containing such a list,
  66 in which there are commands to set the option values.
  67 Type \\[describe-mode] in that buffer for a list of commands.
  68
  69 The Custom feature is intended to make this obsolete."
  70   (interactive)
  71   (list-options)
  72   (pop-to-buffer "*List Options*"))
  73
  74 (defvar Edit-options-mode-map
  75   (let ((map (make-keymap)))
  76     (define-key map "s" 'Edit-options-set)
  77     (define-key map "x" 'Edit-options-toggle)
  78     (define-key map "1" 'Edit-options-t)
  79     (define-key map "0" 'Edit-options-nil)
  80     (define-key map "p" 'backward-paragraph)
  81     (define-key map " " 'forward-paragraph)
  82     (define-key map "n" 'forward-paragraph)
  83     map)
  84   "")
  85
  86 ;; Edit Options mode is suitable only for specially formatted data.
  87 (put 'Edit-options-mode 'mode-class 'special)
  88
  89 (defun Edit-options-mode ()
  90   "\\<Edit-options-mode-map>\
  91 Major mode for editing Emacs user option settings.
  92 Special commands are:
  93 \\[Edit-options-set] -- set variable point points at.  New value read using minibuffer.
  94 \\[Edit-options-toggle] -- toggle variable, t -> nil, nil -> t.
  95 \\[Edit-options-t] -- set variable to t.
  96 \\[Edit-options-nil] -- set variable to nil.
  97 Changed values made by these commands take effect immediately.
  98
  99 Each variable description is a paragraph.
 100 For convenience, the characters \\[backward-paragraph] and \\[forward-paragraph] move back and forward by paragraphs."
 101   (kill-all-local-variables)
 102   (set-syntax-table emacs-lisp-mode-syntax-table)
 103   (use-local-map Edit-options-mode-map)
 104   (make-local-variable 'paragraph-separate)
 105   (setq paragraph-separate "[^\^@-\^?]")
 106   (make-local-variable 'paragraph-start)
 107   (setq paragraph-start "\t")
 108   (setq truncate-lines t)
 109   (setq major-mode 'Edit-options-mode)
 110   (setq mode-name "Options")
 111   (run-hooks 'Edit-options-mode-hook))
 112
 113 (defun Edit-options-set () (interactive)
 114   (Edit-options-modify
 115    (lambda (var) (eval-minibuffer (concat "New " (symbol-name var) ": ")))))
 116
 117 (defun Edit-options-toggle () (interactive)
 118   (Edit-options-modify (lambda (var) (not (symbol-value var)))))
 119
 120 (defun Edit-options-t () (interactive)
 121   (Edit-options-modify (lambda (var) t)))
 122
 123 (defun Edit-options-nil () (interactive)
 124   (Edit-options-modify (lambda (var) nil)))
 125
 126 (defun Edit-options-modify (modfun)
 127   (save-excursion
 128    (let ((buffer-read-only nil) var pos)
 129      (re-search-backward "^;; \\|\\`")
 130      (forward-char 3)
 131      (setq pos (point))
 132      (save-restriction
 133        (narrow-to-region pos (progn (end-of-line) (1- (point))))
 134        (goto-char pos)
 135        (setq var (read (current-buffer))))
 136      (goto-char pos)
 137      (forward-line 1)
 138      (forward-char 1)
 139      (save-excursion
 140        (set var (funcall modfun var)))
 141      (kill-sexp 1)
 142      (prin1 (symbol-value var) (current-buffer)))))
 143
 144 (provide 'options)
 145
 146 ;;; options.el ends here