lisp/descr-text.el

   1 ;;; descr-text.el --- describe text mode
   2
   3 ;; Copyright (c) 1994, 1995, 1996, 2001, 02, 03 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 (eval-when-compile (require 'button))
  32
  33 (defun describe-text-done ()
  34   "Delete the current window or bury the current buffer."
  35   (interactive)
  36   (if (> (count-windows) 1)
  37       (delete-window)
  38     (bury-buffer)))
  39
  40 (defvar describe-text-mode-map
  41   (let ((map (make-sparse-keymap)))
  42     (set-keymap-parent map widget-keymap)
  43     map)
  44   "Keymap for `describe-text-mode'.")
  45
  46 (defcustom describe-text-mode-hook nil
  47   "List of hook functions ran by `describe-text-mode'."
  48   :type 'hook
  49   :group 'facemenu)
  50
  51 (defun describe-text-mode ()
  52   "Major mode for buffers created by `describe-char'.
  53
  54 \\{describe-text-mode-map}
  55 Entry to this mode calls the value of `describe-text-mode-hook'
  56 if that value is non-nil."
  57   (kill-all-local-variables)
  58   (setq major-mode 'describe-text-mode
  59         mode-name "Describe-Text")
  60   (use-local-map describe-text-mode-map)
  61   (widget-setup)
  62   (add-hook 'change-major-mode-hook 'font-lock-defontify nil t)
  63   (run-hooks 'describe-text-mode-hook))
  64
  65 ;;; Describe-Text Utilities.
  66
  67 (defun describe-text-widget (widget)
  68   "Insert text to describe WIDGET in the current buffer."
  69   (widget-create 'link
  70                  :notify `(lambda (&rest ignore)
  71                             (widget-browse ',widget))
  72                  (format "%S" (if (symbolp widget)
  73                                   widget
  74                                 (car widget))))
  75   (widget-insert " ")
  76   (widget-create 'info-link :tag "widget" "(widget)Top"))
  77
  78 (defun describe-text-sexp (sexp)
  79   "Insert a short description of SEXP in the current buffer."
  80   (let ((pp (condition-case signal
  81                 (pp-to-string sexp)
  82               (error (prin1-to-string signal)))))
  83     (when (string-match "\n\\'" pp)
  84       (setq pp (substring pp 0 (1- (length pp)))))
  85     (if (cond ((string-match "\n" pp)
  86                nil)
  87               ((> (length pp) (- (window-width) (current-column)))
  88                nil)
  89               (t t))
  90         (widget-insert pp)
  91       (widget-create 'push-button
  92                      :tag "show"
  93                      :action (lambda (widget &optional event)
  94                                (with-output-to-temp-buffer
  95                                    "*Pp Eval Output*"
  96                                  (princ (widget-get widget :value))))
  97                      pp))))
  98
  99 (defun describe-property-list (properties)
 100   "Insert a description of PROPERTIES in the current buffer.
 101 PROPERTIES should be a list of overlay or text properties.
 102 The `category' property is made into a widget button that call
 103 `describe-text-category' when pushed."
 104   ;; Sort the properties by the size of their value.
 105   (dolist (elt (sort (let ((ret nil)
 106                            (key nil)
 107                            (val nil)
 108                            (len nil))
 109                        (while properties
 110                          (setq key (pop properties)
 111                                val (pop properties)
 112                                len 0)
 113                          (unless (or (eq key 'category)
 114                                      (widgetp val))
 115                            (setq val (pp-to-string val)
 116                                  len (length val)))
 117                          (push (list key val len) ret))
 118                        ret)
 119                      (lambda (a b)
 120                        (< (nth 2 a)
 121                           (nth 2 b)))))
 122     (let ((key (nth 0 elt))
 123           (value (nth 1 elt)))
 124       (widget-insert (propertize (format "  %-20s " key)
 125                                  'font-lock-face 'italic))
 126       (cond ((eq key 'category)
 127              (widget-create 'link
 128                             :notify `(lambda (&rest ignore)
 129                                        (describe-text-category ',value))
 130                             (format "%S" value)))
 131             ((widgetp value)
 132              (describe-text-widget value))
 133             (t
 134              (widget-insert value))))
 135     (widget-insert "\n")))
 136 \f
 137 ;;; Describe-Text Commands.
 138
 139 (defun describe-text-category (category)
 140   "Describe a text property category."
 141   (interactive "S")
 142   (save-excursion
 143     (with-output-to-temp-buffer "*Help*"
 144       (set-buffer standard-output)
 145       (widget-insert "Category " (format "%S" category) ":\n\n")
 146       (describe-property-list (symbol-plist category))
 147       (describe-text-mode)
 148       (goto-char (point-min)))))
 149
 150 ;;;###autoload
 151 (defun describe-text-properties (pos &optional output-buffer)
 152   "Describe widgets, buttons, overlays and text properties at POS.
 153 Interactively, describe them for the character after point.
 154 If optional second argument OUTPUT-BUFFER is non-nil,
 155 insert the output into that buffer, and don't initialize or clear it
 156 otherwise."
 157   (interactive "d")
 158   (if (>= pos (point-max))
 159       (error "No character follows specified position"))
 160   (if output-buffer
 161       (describe-text-properties-1 pos output-buffer)
 162     (if (not (or (text-properties-at pos) (overlays-at pos)))
 163         (message "This is plain text.")
 164       (let ((buffer (current-buffer)))
 165         (when (eq buffer (get-buffer "*Help*"))
 166           (error "Can't do self inspection"))
 167         (save-excursion
 168           (with-output-to-temp-buffer "*Help*"
 169             (set-buffer standard-output)
 170             (setq output-buffer (current-buffer))
 171             (widget-insert "Text content at position " (format "%d" pos) ":\n\n")
 172             (with-current-buffer buffer
 173               (describe-text-properties-1 pos output-buffer))
 174             (describe-text-mode)
 175             (goto-char (point-min))))))))
 176
 177 (defun describe-text-properties-1 (pos output-buffer)
 178   (let* ((properties (text-properties-at pos))
 179          (overlays (overlays-at pos))
 180          overlay
 181          (wid-field (get-char-property pos 'field))
 182          (wid-button (get-char-property pos 'button))
 183          (wid-doc (get-char-property pos 'widget-doc))
 184          ;; If button.el is not loaded, we have no buttons in the text.
 185          (button (and (fboundp 'button-at) (button-at pos)))
 186          (button-type (and button (button-type button)))
 187          (button-label (and button (button-label button)))
 188          (widget (or wid-field wid-button wid-doc)))
 189     (with-current-buffer output-buffer
 190       ;; Widgets
 191       (when (widgetp widget)
 192         (newline)
 193         (widget-insert (cond (wid-field "This is an editable text area")
 194                              (wid-button "This is an active area")
 195                              (wid-doc "This is documentation text")))
 196         (widget-insert " of a ")
 197         (describe-text-widget widget)
 198         (widget-insert ".\n\n"))
 199       ;; Buttons
 200       (when (and button (not (widgetp wid-button)))
 201         (newline)
 202         (widget-insert "Here is a " (format "%S" button-type)
 203                        " button labeled `" button-label "'.\n\n"))
 204       ;; Overlays
 205       (when overlays
 206         (newline)
 207         (if (eq (length overlays) 1)
 208             (widget-insert "There is an overlay here:\n")
 209           (widget-insert "There are " (format "%d" (length overlays))
 210                          " overlays here:\n"))
 211         (dolist (overlay overlays)
 212           (widget-insert " From " (format "%d" (overlay-start overlay))
 213                          " to " (format "%d" (overlay-end overlay)) "\n")
 214           (describe-property-list (overlay-properties overlay)))
 215         (widget-insert "\n"))
 216       ;; Text properties
 217       (when properties
 218         (newline)
 219         (widget-insert "There are text properties here:\n")
 220         (describe-property-list properties)))))
 221 \f
 222 ;;; We cannot use the UnicodeData.txt file as such; it is not free.
 223 ;;; We can turn that info a different format and release the result
 224 ;;; as free data.  When that is done, we could reinstate the code below.
 225 ;;; For the mean time, here is a dummy placeholder.
 226 ;;;  -- rms
 227 (defun describe-char-unicode-data (char) nil)
 228
 229 ;;; (defcustom describe-char-unicodedata-file nil
 230 ;;;   "Location of Unicode data file.
 231 ;;; This is the UnicodeData.txt file from the Unicode consortium, used for
 232 ;;; diagnostics.  If it is non-nil `describe-char-after' will print data
 233 ;;; looked up from it.  This facility is mostly of use to people doing
 234 ;;; multilingual development.
 235
 236 ;;; This is a fairly large file, not typically present on GNU systems.  At
 237 ;;; the time of writing it is at
 238 ;;; <URL:ftp://www.unicode.org/Public/UNIDATA/UnicodeData.txt>."
 239 ;;;   :group 'mule
 240 ;;;   :version "21.5"
 241 ;;;   :type '(choice (const :tag "None" nil)
 242 ;;;              file))
 243
 244 ;;; ;; We could convert the unidata file into a Lispy form once-for-all
 245 ;;; ;; and distribute it for loading on demand.  It might be made more
 246 ;;; ;; space-efficient by splitting strings word-wise and replacing them
 247 ;;; ;; with lists of symbols interned in a private obarray, e.g.
 248 ;;; ;; "LATIN SMALL LETTER A" => '(LATIN SMALL LETTER A).
 249
 250 ;;; ;; Fixme: Check whether this needs updating for Unicode 4.
 251 ;;; (defun describe-char-unicode-data (char)
 252 ;;;   "Return a list of Unicode data for unicode CHAR.
 253 ;;; Each element is a list of a property description and the property value.
 254 ;;; The list is null if CHAR isn't found in `describe-char-unicodedata-file'."
 255 ;;;   (when describe-char-unicodedata-file
 256 ;;;     (unless (file-exists-p describe-char-unicodedata-file)
 257 ;;;       (error "`unicodedata-file' %s not found" describe-char-unicodedata-file))
 258 ;;;     (save-excursion
 259 ;;;       ;; Find file in fundamental mode to avoid, e.g. flyspell turned
 260 ;;;       ;; on for .txt.  Don't use RAWFILE arg in case of DOS line endings.
 261 ;;;       (set-buffer (let ((auto-mode-alist))
 262 ;;;                 (find-file-noselect describe-char-unicodedata-file)))
 263 ;;;       (goto-char (point-min))
 264 ;;;       (let ((hex (format "%04X" char))
 265 ;;;         found first last)
 266 ;;;     (if (re-search-forward (concat "^" hex) nil t)
 267 ;;;         (setq found t)
 268 ;;;       ;; It's not listed explicitly.  Look for ranges, e.g. CJK
 269 ;;;       ;; ideographs, and check whether it's in one of them.
 270 ;;;       (while (and (re-search-forward "^\\([^;]+\\);[^;]+First>;" nil t)
 271 ;;;                   (>= char (setq first
 272 ;;;                                  (string-to-number (match-string 1) 16)))
 273 ;;;                   (progn
 274 ;;;                     (forward-line 1)
 275 ;;;                     (looking-at "^\\([^;]+\\);[^;]+Last>;")
 276 ;;;                     (> char
 277 ;;;                        (setq last
 278 ;;;                              (string-to-number (match-string 1) 16))))))
 279 ;;;       (if (and (>= char first)
 280 ;;;                (<= char last))
 281 ;;;           (setq found t)))
 282 ;;;     (if found
 283 ;;;         (let ((fields (mapcar (lambda (elt)
 284 ;;;                                 (if (> (length elt) 0)
 285 ;;;                                     elt))
 286 ;;;                               (cdr (split-string
 287 ;;;                                     (buffer-substring
 288 ;;;                                      (line-beginning-position)
 289 ;;;                                      (line-end-position))
 290 ;;;                                     ";")))))
 291 ;;;           ;; The length depends on whether the last field was empty.
 292 ;;;           (unless (or (= 13 (length fields))
 293 ;;;                       (= 14 (length fields)))
 294 ;;;             (error "Invalid contents in %s" describe-char-unicodedata-file))
 295 ;;;           ;; The field names and values lists are slightly
 296 ;;;           ;; modified from Mule-UCS unidata.el.
 297 ;;;           (list
 298 ;;;            (list "Name" (let ((name (nth 0 fields)))
 299 ;;;                           ;; Check for <..., First>, <..., Last>
 300 ;;;                           (if (string-match "\\`\\(<[^,]+\\)," name)
 301 ;;;                               (concat (match-string 1 name) ">")
 302 ;;;                             name)))
 303 ;;;            (list "Category"
 304 ;;;                  (cdr (assoc
 305 ;;;                        (nth 1 fields)
 306 ;;;                        '(("Lu" . "uppercase letter")
 307 ;;;                          ("Ll" . "lowercase letter")
 308 ;;;                          ("Lt" . "titlecase letter")
 309 ;;;                          ("Mn" . "non-spacing mark")
 310 ;;;                          ("Mc" . "spacing-combining mark")
 311 ;;;                          ("Me" . "enclosing mark")
 312 ;;;                          ("Nd" . "decimal digit")
 313 ;;;                          ("Nl" . "letter number")
 314 ;;;                          ("No" . "other number")
 315 ;;;                          ("Zs" . "space separator")
 316 ;;;                          ("Zl" . "line separator")
 317 ;;;                          ("Zp" . "paragraph separator")
 318 ;;;                          ("Cc" . "other control")
 319 ;;;                          ("Cf" . "other format")
 320 ;;;                          ("Cs" . "surrogate")
 321 ;;;                          ("Co" . "private use")
 322 ;;;                          ("Cn" . "not assigned")
 323 ;;;                          ("Lm" . "modifier letter")
 324 ;;;                          ("Lo" . "other letter")
 325 ;;;                          ("Pc" . "connector punctuation")
 326 ;;;                          ("Pd" . "dash punctuation")
 327 ;;;                          ("Ps" . "open punctuation")
 328 ;;;                          ("Pe" . "close punctuation")
 329 ;;;                          ("Pi" . "initial-quotation punctuation")
 330 ;;;                          ("Pf" . "final-quotation punctuation")
 331 ;;;                          ("Po" . "other punctuation")
 332 ;;;                          ("Sm" . "math symbol")
 333 ;;;                          ("Sc" . "currency symbol")
 334 ;;;                          ("Sk" . "modifier symbol")
 335 ;;;                          ("So" . "other symbol")))))
 336 ;;;            (list "Combining class"
 337 ;;;                  (cdr (assoc
 338 ;;;                        (string-to-number (nth 2 fields))
 339 ;;;                        '((0 . "Spacing")
 340 ;;;                          (1 . "Overlays and interior")
 341 ;;;                          (7 . "Nuktas")
 342 ;;;                          (8 . "Hiragana/Katakana voicing marks")
 343 ;;;                          (9 . "Viramas")
 344 ;;;                          (10 . "Start of fixed position classes")
 345 ;;;                          (199 . "End of fixed position classes")
 346 ;;;                          (200 . "Below left attached")
 347 ;;;                          (202 . "Below attached")
 348 ;;;                          (204 . "Below right attached")
 349 ;;;                          (208 . "Left attached (reordrant around \
 350 ;;; single base character)")
 351 ;;;                          (210 . "Right attached")
 352 ;;;                          (212 . "Above left attached")
 353 ;;;                          (214 . "Above attached")
 354 ;;;                          (216 . "Above right attached")
 355 ;;;                          (218 . "Below left")
 356 ;;;                          (220 . "Below")
 357 ;;;                          (222 . "Below right")
 358 ;;;                          (224 . "Left (reordrant around single base \
 359 ;;; character)")
 360 ;;;                          (226 . "Right")
 361 ;;;                          (228 . "Above left")
 362 ;;;                          (230 . "Above")
 363 ;;;                          (232 . "Above right")
 364 ;;;                          (233 . "Double below")
 365 ;;;                          (234 . "Double above")
 366 ;;;                          (240 . "Below (iota subscript)")))))
 367 ;;;            (list "Bidi category"
 368 ;;;                  (cdr (assoc
 369 ;;;                        (nth 3 fields)
 370 ;;;                        '(("L" . "Left-to-Right")
 371 ;;;                          ("LRE" . "Left-to-Right Embedding")
 372 ;;;                          ("LRO" . "Left-to-Right Override")
 373 ;;;                          ("R" . "Right-to-Left")
 374 ;;;                          ("AL" . "Right-to-Left Arabic")
 375 ;;;                          ("RLE" . "Right-to-Left Embedding")
 376 ;;;                          ("RLO" . "Right-to-Left Override")
 377 ;;;                          ("PDF" . "Pop Directional Format")
 378 ;;;                          ("EN" . "European Number")
 379 ;;;                          ("ES" . "European Number Separator")
 380 ;;;                          ("ET" . "European Number Terminator")
 381 ;;;                          ("AN" . "Arabic Number")
 382 ;;;                          ("CS" . "Common Number Separator")
 383 ;;;                          ("NSM" . "Non-Spacing Mark")
 384 ;;;                          ("BN" . "Boundary Neutral")
 385 ;;;                          ("B" . "Paragraph Separator")
 386 ;;;                          ("S" . "Segment Separator")
 387 ;;;                          ("WS" . "Whitespace")
 388 ;;;                          ("ON" . "Other Neutrals")))))
 389 ;;;            (list
 390 ;;;             "Decomposition"
 391 ;;;             (if (nth 4 fields)
 392 ;;;                 (let* ((parts (split-string (nth 4 fields)))
 393 ;;;                        (info (car parts)))
 394 ;;;                   (if (string-match "\\`<\\(.+\\)>\\'" info)
 395 ;;;                       (setq info (match-string 1 info))
 396 ;;;                     (setq info nil))
 397 ;;;                   (if info (setq parts (cdr parts)))
 398 ;;;                   ;; Maybe printing ? for unrepresentable unicodes
 399 ;;;                   ;; here and below should be changed?
 400 ;;;                   (setq parts (mapconcat
 401 ;;;                                (lambda (arg)
 402 ;;;                                  (string (or (decode-char
 403 ;;;                                               'ucs
 404 ;;;                                               (string-to-number arg 16))
 405 ;;;                                              ??)))
 406 ;;;                                parts " "))
 407 ;;;                   (concat info parts))))
 408 ;;;            (list "Decimal digit value"
 409 ;;;                  (nth 5 fields))
 410 ;;;            (list "Digit value"
 411 ;;;                  (nth 6 fields))
 412 ;;;            (list "Numeric value"
 413 ;;;                  (nth 7 fields))
 414 ;;;            (list "Mirrored"
 415 ;;;                  (if (equal "Y" (nth 8 fields))
 416 ;;;                      "yes"))
 417 ;;;            (list "Old name" (nth 9 fields))
 418 ;;;            (list "ISO 10646 comment" (nth 10 fields))
 419 ;;;            (list "Uppercase" (and (nth 11 fields)
 420 ;;;                                   (string (or (decode-char
 421 ;;;                                                'ucs
 422 ;;;                                                (string-to-number
 423 ;;;                                                 (nth 11 fields) 16))
 424 ;;;                                               ??))))
 425 ;;;            (list "Lowercase" (and (nth 12 fields)
 426 ;;;                                   (string (or (decode-char
 427 ;;;                                                'ucs
 428 ;;;                                                (string-to-number
 429 ;;;                                                 (nth 12 fields) 16))
 430 ;;;                                               ??))))
 431 ;;;            (list "Titlecase" (and (nth 13 fields)
 432 ;;;                                   (string (or (decode-char
 433 ;;;                                                'ucs
 434 ;;;                                                (string-to-number
 435 ;;;                                                 (nth 13 fields) 16))
 436 ;;;                                               ??)))))))))))
 437 \f
 438 ;;;###autoload
 439 (defun describe-char (pos)
 440   "Describe the character after POS (interactively, the character after point).
 441 The information includes character code, charset and code points in it,
 442 syntax, category, how the character is encoded in a file,
 443 character composition information (if relevant),
 444 as well as widgets, buttons, overlays, and text properties."
 445   (interactive "d")
 446   (if (>= pos (point-max))
 447       (error "No character follows specified position"))
 448   (let* ((char (char-after pos))
 449          (charset (char-charset char))
 450          (buffer (current-buffer))
 451          (composition (find-composition pos nil nil t))
 452          (composed (if composition (buffer-substring (car composition)
 453                                                      (nth 1 composition))))
 454          (multibyte-p enable-multibyte-characters)
 455          item-list max-width unicode)
 456     (if (eq charset 'unknown)
 457         (setq item-list
 458               `(("character"
 459                  ,(format "%s (0%o, %d, 0x%x) -- invalid character code"
 460                           (if (< char 256)
 461                               (single-key-description char)
 462                             (char-to-string char))
 463                           char char char))))
 464
 465       (if (or (< char 256)
 466               (memq 'mule-utf-8 (find-coding-systems-region pos (1+ pos)))
 467               (get-char-property pos 'untranslated-utf-8))
 468           (setq unicode (or (get-char-property pos 'untranslated-utf-8)
 469                             (encode-char char 'ucs))))
 470       (setq item-list
 471             `(("character"
 472                ,(format "%s (0%o, %d, 0x%x%s)" (if (< char 256)
 473                                                  (single-key-description char)
 474                                                (char-to-string char))
 475                         char char char
 476                         (if unicode
 477                             (format ", U+%04X" unicode)
 478                           "")))
 479               ("charset"
 480                ,(symbol-name charset)
 481                ,(format "(%s)" (charset-description charset)))
 482               ("code point"
 483                ,(let ((split (split-char char)))
 484                   (if (= (charset-dimension charset) 1)
 485                       (format "%d" (nth 1 split))
 486                     (format "%d %d" (nth 1 split) (nth 2 split)))))
 487               ("syntax"
 488                ,(let ((syntax (syntax-after pos)))
 489                   (with-temp-buffer
 490                     (internal-describe-syntax-value syntax)
 491                     (buffer-string))))
 492               ("category"
 493                ,@(let ((category-set (char-category-set char)))
 494                    (if (not category-set)
 495                        '("-- none --")
 496                      (mapcar #'(lambda (x) (format "%c:%s  "
 497                                                    x (category-docstring x)))
 498                              (category-set-mnemonics category-set)))))
 499               ,@(let ((props (aref char-code-property-table char))
 500                       ps)
 501                   (when props
 502                     (while props
 503                       (push (format "%s:" (pop props)) ps)
 504                       (push (format "%s;" (pop props)) ps))
 505                     (list (cons "Properties" (nreverse ps)))))
 506               ("buffer code"
 507                ,(encoded-string-description
 508                  (string-as-unibyte (char-to-string char)) nil))
 509               ("file code"
 510                ,@(let* ((coding buffer-file-coding-system)
 511                         (encoded (encode-coding-char char coding)))
 512                    (if encoded
 513                        (list (encoded-string-description encoded coding)
 514                              (format "(encoded by coding system %S)" coding))
 515                      (list "not encodable by coding system"
 516                            (symbol-name coding)))))
 517               ,(if (display-graphic-p (selected-frame))
 518                    (list "font" (or (internal-char-font pos)
 519                                     "-- none --"))
 520                  (list "terminal code"
 521                        (let* ((coding (terminal-coding-system))
 522                               (encoded (encode-coding-char char coding)))
 523                          (if encoded
 524                              (encoded-string-description encoded coding)
 525                            "not encodable"))))
 526               ,@(let ((unicodedata (and unicode
 527                                         (describe-char-unicode-data unicode))))
 528                   (if unicodedata
 529                       (cons (list "Unicode data" " ") unicodedata))))))
 530     (setq max-width (apply #'max (mapcar #'(lambda (x) (length (car x)))
 531                                          item-list)))
 532     (when (eq (current-buffer) (get-buffer "*Help*"))
 533       (error "Can't describe char in Help buffer"))
 534     (with-output-to-temp-buffer "*Help*"
 535       (with-current-buffer standard-output
 536         (set-buffer-multibyte multibyte-p)
 537         (let ((formatter (format "%%%ds:" max-width)))
 538           (dolist (elt item-list)
 539             (when (cadr elt)
 540               (insert (format formatter (car elt)))
 541               (dolist (clm (cdr elt))
 542                 (when (>= (+ (current-column)
 543                              (or (string-match "\n" clm)
 544                                  (string-width clm)) 1)
 545                           (frame-width))
 546                   (insert "\n")
 547                   (indent-to (1+ max-width)))
 548                 (insert " " clm))
 549               (insert "\n"))))
 550         (when composition
 551           (insert "\nComposed with the "
 552                   (cond
 553                    ((eq pos (car composition)) "following ")
 554                    ((eq (1+ pos) (cadr composition)) "preceding ")
 555                    (t ""))
 556                   "character(s) `"
 557                   (cond
 558                    ((eq pos (car composition)) (substring composed 1))
 559                    ((eq (1+ pos) (cadr composition)) (substring composed 0 -1))
 560                    (t (concat (substring composed 0 (- pos (car composition)))
 561                               "' and `"
 562                               (substring composed (- (1+ pos) (car composition))))))
 563
 564                   "' to form `" composed "'")
 565           (if (nth 3 composition)
 566               (insert ".\n")
 567             (insert "\nby the rule ("
 568                     (mapconcat (lambda (x)
 569                                  (format (if (consp x) "%S" "?%c") x))
 570                                (nth 2 composition)
 571                                " ")
 572                     ").\n"
 573                     "See the variable `reference-point-alist' for "
 574                     "the meaning of the rule.\n")))
 575
 576         (let ((output (current-buffer)))
 577           (with-current-buffer buffer
 578             (describe-text-properties pos output))
 579           (describe-text-mode))))))
 580
 581 (defalias 'describe-char-after 'describe-char)
 582 (make-obsolete 'describe-char-after 'describe-char "21.5")
 583
 584 (provide 'descr-text)
 585
 586 ;;; descr-text.el ends here