lisp/descr-text.el

   1 ;;; descr-text.el --- describe text mode
   2
   3 ;; Copyright (c) 1994, 1995, 1996, 2001, 2002 Free Software Foundation, Inc.
   4
   5 ;; Author: Boris Goldowsky <boris@gnu.org>
   6 ;; Keywords: faces
   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., 59 Temple Place - Suite 330,
  23 ;; Boston, MA 02111-1307, USA.
  24
  25 ;;; Commentary:
  26
  27 ;;; Describe-Text Mode.
  28
  29 ;;; Code:
  30
  31 (defun describe-text-done ()
  32   "Delete the current window or bury the current buffer."
  33   (interactive)
  34   (if (> (count-windows) 1)
  35       (delete-window)
  36     (bury-buffer)))
  37
  38 (defvar describe-text-mode-map
  39   (let ((map (make-sparse-keymap)))
  40     (set-keymap-parent map widget-keymap)
  41     map)
  42   "Keymap for `describe-text-mode'.")
  43
  44 (defcustom describe-text-mode-hook nil
  45   "List of hook functions ran by `describe-text-mode'."
  46   :type 'hook)
  47
  48 (defun describe-text-mode ()
  49   "Major mode for buffers created by `describe-text-at'.
  50
  51 \\{describe-text-mode-map}
  52 Entry to this mode calls the value of `describe-text-mode-hook'
  53 if that value is non-nil."
  54   (kill-all-local-variables)
  55   (setq major-mode 'describe-text-mode
  56         mode-name "Describe-Text")
  57   (use-local-map describe-text-mode-map)
  58   (widget-setup)
  59   (run-hooks 'describe-text-mode-hook))
  60
  61 ;;; Describe-Text Utilities.
  62
  63 (defun describe-text-widget (widget)
  64   "Insert text to describe WIDGET in the current buffer."
  65   (widget-create 'link
  66                  :notify `(lambda (&rest ignore)
  67                             (widget-browse ',widget))
  68                  (format "%S" (if (symbolp widget)
  69                                   widget
  70                                 (car widget))))
  71   (widget-insert " ")
  72   (widget-create 'info-link :tag "widget" "(widget)Top"))
  73
  74 (defun describe-text-sexp (sexp)
  75   "Insert a short description of SEXP in the current buffer."
  76   (let ((pp (condition-case signal
  77                 (pp-to-string sexp)
  78               (error (prin1-to-string signal)))))
  79     (when (string-match "\n\\'" pp)
  80       (setq pp (substring pp 0 (1- (length pp)))))
  81     (if (cond ((string-match "\n" pp)
  82                nil)
  83               ((> (length pp) (- (window-width) (current-column)))
  84                nil)
  85               (t t))
  86         (widget-insert pp)
  87       (widget-create 'push-button
  88                      :tag "show"
  89                      :action (lambda (widget &optional event)
  90                                (with-output-to-temp-buffer
  91                                    "*Pp Eval Output*"
  92                                  (princ (widget-get widget :value))))
  93                      pp))))
  94
  95 (defun describe-text-properties (properties)
  96   "Insert a description of PROPERTIES in the current buffer.
  97 PROPERTIES should be a list of overlay or text properties.
  98 The `category' property is made into a widget button that call
  99 `describe-text-category' when pushed."
 100   ;; Sort the properties by the size of their value.
 101   (dolist (elt (sort (let ((ret nil)
 102                            (key nil)
 103                            (val nil)
 104                            (len nil))
 105                        (while properties
 106                          (setq key (pop properties)
 107                                val (pop properties)
 108                                len 0)
 109                          (unless (or (eq key 'category)
 110                                      (widgetp val))
 111                            (setq val (pp-to-string val)
 112                                  len (length val)))
 113                          (push (list key val len) ret))
 114                        ret)
 115                      (lambda (a b)
 116                        (< (nth 2 a)
 117                           (nth 2 b)))))
 118     (let ((key (nth 0 elt))
 119           (value (nth 1 elt)))
 120       (widget-insert (propertize (format "  %-20s" key)
 121                                  'font-lock-face 'italic))
 122       (cond ((eq key 'category)
 123              (widget-create 'link
 124                             :notify `(lambda (&rest ignore)
 125                                        (describe-text-category ',value))
 126                             (format "%S" value)))
 127             ((widgetp value)
 128              (describe-text-widget value))
 129             (t
 130              (widget-insert value))))
 131     (widget-insert "\n")))
 132 \f
 133 ;;; Describe-Text Commands.
 134
 135 (defun describe-text-category (category)
 136   "Describe a text property category."
 137   (interactive "S")
 138   (when (get-buffer "*Text Category*")
 139     (kill-buffer "*Text Category*"))
 140   (save-excursion
 141     (with-output-to-temp-buffer "*Text Category*"
 142       (set-buffer "*Text Category*")
 143       (widget-insert "Category " (format "%S" category) ":\n\n")
 144       (describe-text-properties (symbol-plist category))
 145       (describe-text-mode)
 146       (goto-char (point-min)))))
 147
 148 ;;;###autoload
 149 (defun describe-text-at (pos)
 150   "Describe widgets, buttons, overlays and text properties at POS."
 151   (interactive "d")
 152   (when (eq (current-buffer) (get-buffer "*Text Description*"))
 153     (error "Can't do self inspection"))
 154   (let* ((properties (text-properties-at pos))
 155          (overlays (overlays-at pos))
 156          overlay
 157          (wid-field (get-char-property pos 'field))
 158          (wid-button (get-char-property pos 'button))
 159          (wid-doc (get-char-property pos 'widget-doc))
 160          ;; If button.el is not loaded, we have no buttons in the text.
 161          (button (and (fboundp 'button-at) (button-at pos)))
 162          (button-type (and button (button-type button)))
 163          (button-label (and button (button-label button)))
 164          (widget (or wid-field wid-button wid-doc)))
 165     (if (not (or properties overlays))
 166         (message "This is plain text.")
 167       (when (get-buffer "*Text Description*")
 168         (kill-buffer "*Text Description*"))
 169       (save-excursion
 170         (with-output-to-temp-buffer "*Text Description*"
 171           (set-buffer "*Text Description*")
 172           (widget-insert "Text content at position " (format "%d" pos) ":\n\n")
 173           ;; Widgets
 174           (when (widgetp widget)
 175             (widget-insert (cond (wid-field "This is an editable text area")
 176                                  (wid-button "This is an active area")
 177                                  (wid-doc "This is documentation text")))
 178             (widget-insert " of a ")
 179             (describe-text-widget widget)
 180             (widget-insert ".\n\n"))
 181           ;; Buttons
 182           (when (and button (not (widgetp wid-button)))
 183             (widget-insert "Here is a " (format "%S" button-type)
 184                            " button labeled `" button-label "'.\n\n"))
 185           ;; Overlays
 186           (when overlays
 187             (if (eq (length overlays) 1)
 188                 (widget-insert "There is an overlay here:\n")
 189               (widget-insert "There are " (format "%d" (length overlays))
 190                              " overlays here:\n"))
 191             (dolist (overlay overlays)
 192               (widget-insert " From " (format "%d" (overlay-start overlay))
 193                              " to " (format "%d" (overlay-end overlay)) "\n")
 194               (describe-text-properties (overlay-properties overlay)))
 195             (widget-insert "\n"))
 196           ;; Text properties
 197           (when properties
 198             (widget-insert "There are text properties here:\n")
 199             (describe-text-properties properties))
 200           (describe-text-mode)
 201           (goto-char (point-min)))))))
 202
 203 (provide 'descr-text)
 204
 205 ;;; descr-text.el ends here