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[emacs.git] / lisp / descr-text.el
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1 ;;; descr-text.el --- describe text mode
3 ;; Copyright (c) 1994, 1995, 1996, 2001, 2002 Free Software Foundation, Inc.
5 ;; Author: Boris Goldowsky <boris@gnu.org>
6 ;; Keywords: faces
8 ;; This file is part of GNU Emacs.
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.
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.
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.
25 ;;; Commentary:
27 ;;; Describe-Text Mode.
29 ;;; Code:
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)))
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'.")
44 (defcustom describe-text-mode-hook nil
45 "List of hook functions ran by `describe-text-mode'."
46 :type 'hook
47 :group 'facemenu)
49 (defun describe-text-mode ()
50 "Major mode for buffers created by `describe-char'.
52 \\{describe-text-mode-map}
53 Entry to this mode calls the value of `describe-text-mode-hook'
54 if that value is non-nil."
55 (kill-all-local-variables)
56 (setq major-mode 'describe-text-mode
57 mode-name "Describe-Text")
58 (use-local-map describe-text-mode-map)
59 (widget-setup)
60 (add-hook 'change-major-mode-hook 'font-lock-defontify nil t)
61 (run-hooks 'describe-text-mode-hook))
63 ;;; Describe-Text Utilities.
65 (defun describe-text-widget (widget)
66 "Insert text to describe WIDGET in the current buffer."
67 (widget-create 'link
68 :notify `(lambda (&rest ignore)
69 (widget-browse ',widget))
70 (format "%S" (if (symbolp widget)
71 widget
72 (car widget))))
73 (widget-insert " ")
74 (widget-create 'info-link :tag "widget" "(widget)Top"))
76 (defun describe-text-sexp (sexp)
77 "Insert a short description of SEXP in the current buffer."
78 (let ((pp (condition-case signal
79 (pp-to-string sexp)
80 (error (prin1-to-string signal)))))
81 (when (string-match "\n\\'" pp)
82 (setq pp (substring pp 0 (1- (length pp)))))
83 (if (cond ((string-match "\n" pp)
84 nil)
85 ((> (length pp) (- (window-width) (current-column)))
86 nil)
87 (t t))
88 (widget-insert pp)
89 (widget-create 'push-button
90 :tag "show"
91 :action (lambda (widget &optional event)
92 (with-output-to-temp-buffer
93 "*Pp Eval Output*"
94 (princ (widget-get widget :value))))
95 pp))))
97 (defun describe-property-list (properties)
98 "Insert a description of PROPERTIES in the current buffer.
99 PROPERTIES should be a list of overlay or text properties.
100 The `category' property is made into a widget button that call
101 `describe-text-category' when pushed."
102 ;; Sort the properties by the size of their value.
103 (dolist (elt (sort (let ((ret nil)
104 (key nil)
105 (val nil)
106 (len nil))
107 (while properties
108 (setq key (pop properties)
109 val (pop properties)
110 len 0)
111 (unless (or (eq key 'category)
112 (widgetp val))
113 (setq val (pp-to-string val)
114 len (length val)))
115 (push (list key val len) ret))
116 ret)
117 (lambda (a b)
118 (< (nth 2 a)
119 (nth 2 b)))))
120 (let ((key (nth 0 elt))
121 (value (nth 1 elt)))
122 (widget-insert (propertize (format " %-20s " key)
123 'font-lock-face 'italic))
124 (cond ((eq key 'category)
125 (widget-create 'link
126 :notify `(lambda (&rest ignore)
127 (describe-text-category ',value))
128 (format "%S" value)))
129 ((widgetp value)
130 (describe-text-widget value))
132 (widget-insert value))))
133 (widget-insert "\n")))
135 ;;; Describe-Text Commands.
137 (defun describe-text-category (category)
138 "Describe a text property category."
139 (interactive "S")
140 (save-excursion
141 (with-output-to-temp-buffer "*Help*"
142 (set-buffer standard-output)
143 (widget-insert "Category " (format "%S" category) ":\n\n")
144 (describe-property-list (symbol-plist category))
145 (describe-text-mode)
146 (goto-char (point-min)))))
148 ;;;###autoload
149 (defun describe-text-properties (pos &optional output-buffer)
150 "Describe widgets, buttons, overlays and text properties at POS.
151 Interactively, describe them for the character after point.
152 If optional second argument OUTPUT-BUFFER is non-nil,
153 insert the output into that buffer, and don't initialize or clear it
154 otherwise."
155 (interactive "d")
156 (if (>= pos (point-max))
157 (error "No character follows specified position"))
158 (if output-buffer
159 (describe-text-properties-1 pos output-buffer)
160 (if (not (or (text-properties-at pos) (overlays-at pos)))
161 (message "This is plain text.")
162 (let ((buffer (current-buffer)))
163 (when (eq buffer (get-buffer "*Help*"))
164 (error "Can't do self inspection"))
165 (save-excursion
166 (with-output-to-temp-buffer "*Help*"
167 (set-buffer standard-output)
168 (setq output-buffer (current-buffer))
169 (widget-insert "Text content at position " (format "%d" pos) ":\n\n")
170 (with-current-buffer buffer
171 (describe-text-properties-1 pos output-buffer))
172 (describe-text-mode)
173 (goto-char (point-min))))))))
175 (defun describe-text-properties-1 (pos output-buffer)
176 (let* ((properties (text-properties-at pos))
177 (overlays (overlays-at pos))
178 overlay
179 (wid-field (get-char-property pos 'field))
180 (wid-button (get-char-property pos 'button))
181 (wid-doc (get-char-property pos 'widget-doc))
182 ;; If button.el is not loaded, we have no buttons in the text.
183 (button (and (fboundp 'button-at) (button-at pos)))
184 (button-type (and button (button-type button)))
185 (button-label (and button (button-label button)))
186 (widget (or wid-field wid-button wid-doc)))
187 (with-current-buffer output-buffer
188 ;; Widgets
189 (when (widgetp widget)
190 (newline)
191 (widget-insert (cond (wid-field "This is an editable text area")
192 (wid-button "This is an active area")
193 (wid-doc "This is documentation text")))
194 (widget-insert " of a ")
195 (describe-text-widget widget)
196 (widget-insert ".\n\n"))
197 ;; Buttons
198 (when (and button (not (widgetp wid-button)))
199 (newline)
200 (widget-insert "Here is a " (format "%S" button-type)
201 " button labeled `" button-label "'.\n\n"))
202 ;; Overlays
203 (when overlays
204 (newline)
205 (if (eq (length overlays) 1)
206 (widget-insert "There is an overlay here:\n")
207 (widget-insert "There are " (format "%d" (length overlays))
208 " overlays here:\n"))
209 (dolist (overlay overlays)
210 (widget-insert " From " (format "%d" (overlay-start overlay))
211 " to " (format "%d" (overlay-end overlay)) "\n")
212 (describe-property-list (overlay-properties overlay)))
213 (widget-insert "\n"))
214 ;; Text properties
215 (when properties
216 (newline)
217 (widget-insert "There are text properties here:\n")
218 (describe-property-list properties)))))
220 ;;;###autoload
221 (defun describe-char (pos)
222 "Describe the character after POS (interactively, the character after point).
223 The information includes character code, charset and code points in it,
224 syntax, category, how the character is encoded in a file,
225 character composition information (if relevant),
226 as well as widgets, buttons, overlays, and text properties."
227 (interactive "d")
228 (if (>= pos (point-max))
229 (error "No character follows specified position"))
230 (let* ((char (char-after pos))
231 (charset (char-charset char))
232 (buffer (current-buffer))
233 (composition (find-composition pos nil nil t))
234 (composed (if composition (buffer-substring (car composition)
235 (nth 1 composition))))
236 (multibyte-p enable-multibyte-characters)
237 item-list max-width)
238 (if (eq charset 'unknown)
239 (setq item-list
240 `(("character"
241 ,(format "%s (0%o, %d, 0x%x) -- invalid character code"
242 (if (< char 256)
243 (single-key-description char)
244 (char-to-string char))
245 char char char))))
246 (setq item-list
247 `(("character"
248 ,(format "%s (0%o, %d, 0x%x)" (if (< char 256)
249 (single-key-description char)
250 (char-to-string char))
251 char char char))
252 ("charset"
253 ,(symbol-name charset)
254 ,(format "(%s)" (charset-description charset)))
255 ("code point"
256 ,(let ((split (split-char char)))
257 (if (= (charset-dimension charset) 1)
258 (format "%d" (nth 1 split))
259 (format "%d %d" (nth 1 split) (nth 2 split)))))
260 ("syntax"
261 ,(let ((syntax (syntax-after pos)))
262 (with-temp-buffer
263 (internal-describe-syntax-value syntax)
264 (buffer-string))))
265 ("category"
266 ,@(let ((category-set (char-category-set char)))
267 (if (not category-set)
268 '("-- none --")
269 (mapcar #'(lambda (x) (format "%c:%s "
270 x (category-docstring x)))
271 (category-set-mnemonics category-set)))))
272 ,@(let ((props (aref char-code-property-table char))
274 (when props
275 (while props
276 (push (format "%s:" (pop props)) ps)
277 (push (format "%s;" (pop props)) ps))
278 (list (cons "Properties" (nreverse ps)))))
279 ("buffer code"
280 ,(encoded-string-description
281 (string-as-unibyte (char-to-string char)) nil))
282 ("file code"
283 ,@(let* ((coding buffer-file-coding-system)
284 (encoded (encode-coding-char char coding)))
285 (if encoded
286 (list (encoded-string-description encoded coding)
287 (format "(encoded by coding system %S)" coding))
288 (list "not encodable by coding system"
289 (symbol-name coding)))))
290 ,@(if (or (memq 'mule-utf-8
291 (find-coding-systems-region pos (1+ pos)))
292 (get-char-property pos 'untranslated-utf-8))
293 (let ((uc (or (get-char-property pos 'untranslated-utf-8)
294 (encode-char char 'ucs))))
295 (if uc
296 (list (list "Unicode"
297 (format "%04X" uc))))))
298 ,(if (display-graphic-p (selected-frame))
299 (list "font" (or (internal-char-font pos)
300 "-- none --"))
301 (list "terminal code"
302 (let* ((coding (terminal-coding-system))
303 (encoded (encode-coding-char char coding)))
304 (if encoded
305 (encoded-string-description encoded coding)
306 "not encodable")))))))
307 (setq max-width (apply #'max (mapcar #'(lambda (x) (length (car x)))
308 item-list)))
309 (when (eq (current-buffer) (get-buffer "*Help*"))
310 (error "Can't do self inspection"))
311 (with-output-to-temp-buffer "*Help*"
312 (with-current-buffer standard-output
313 (set-buffer-multibyte multibyte-p)
314 (let ((formatter (format "%%%ds:" max-width)))
315 (dolist (elt item-list)
316 (insert (format formatter (car elt)))
317 (dolist (clm (cdr elt))
318 (when (>= (+ (current-column)
319 (or (string-match "\n" clm)
320 (string-width clm)) 1)
321 (frame-width))
322 (insert "\n")
323 (indent-to (1+ max-width)))
324 (insert " " clm))
325 (insert "\n")))
326 (when composition
327 (insert "\nComposed with the "
328 (cond
329 ((eq pos (car composition)) "following ")
330 ((eq (1+ pos) (cadr composition)) "preceding ")
331 (t ""))
332 "character(s) `"
333 (cond
334 ((eq pos (car composition)) (substring composed 1))
335 ((eq (1+ pos) (cadr composition)) (substring composed 0 -1))
336 (t (concat (substring composed 0 (- pos (car composition)))
337 "' and `"
338 (substring composed (- (1+ pos) (car composition))))))
340 "' to form `" composed "'")
341 (if (nth 3 composition)
342 (insert ".\n")
343 (insert "\nby the rule ("
344 (mapconcat (lambda (x)
345 (format (if (consp x) "%S" "?%c") x))
346 (nth 2 composition)
347 " ")
348 ").\n"
349 "See the variable `reference-point-alist' for "
350 "the meaning of the rule.\n")))
352 (let ((output (current-buffer)))
353 (with-current-buffer buffer
354 (describe-text-properties pos output))
355 (describe-text-mode))))))
357 (provide 'descr-text)
359 ;;; descr-text.el ends here