code.delx.au - gnu-emacs/blob - lisp/descr-text.el

   1 ;;; descr-text.el --- describe text mode
   2
   3 ;; Copyright (c) 1994, 95, 96, 2001, 02, 03, 04 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' and `face' properties are made into widget buttons
 103 that call `describe-text-category' or `describe-face' 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 (memq key '(category face))
 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             ((eq key 'face)
 132              (widget-create 'link
 133                             :notify `(lambda (&rest ignore)
 134                                        (describe-face ',value))
 135                             (format "%S" value)))
 136             ((widgetp value)
 137              (describe-text-widget value))
 138             (t
 139              (widget-insert value))))
 140     (widget-insert "\n")))
 141 \f
 142 ;;; Describe-Text Commands.
 143
 144 (defun describe-text-category (category)
 145   "Describe a text property category."
 146   (interactive "S")
 147   (save-excursion
 148     (with-output-to-temp-buffer "*Help*"
 149       (set-buffer standard-output)
 150       (widget-insert "Category " (format "%S" category) ":\n\n")
 151       (describe-property-list (symbol-plist category))
 152       (describe-text-mode)
 153       (goto-char (point-min)))))
 154
 155 ;;;###autoload
 156 (defun describe-text-properties (pos &optional output-buffer)
 157   "Describe widgets, buttons, overlays and text properties at POS.
 158 Interactively, describe them for the character after point.
 159 If optional second argument OUTPUT-BUFFER is non-nil,
 160 insert the output into that buffer, and don't initialize or clear it
 161 otherwise."
 162   (interactive "d")
 163   (if (>= pos (point-max))
 164       (error "No character follows specified position"))
 165   (if output-buffer
 166       (describe-text-properties-1 pos output-buffer)
 167     (if (not (or (text-properties-at pos) (overlays-at pos)))
 168         (message "This is plain text.")
 169       (let ((buffer (current-buffer)))
 170         (when (eq buffer (get-buffer "*Help*"))
 171           (error "Can't do self inspection"))
 172         (save-excursion
 173           (with-output-to-temp-buffer "*Help*"
 174             (set-buffer standard-output)
 175             (setq output-buffer (current-buffer))
 176             (widget-insert "Text content at position " (format "%d" pos) ":\n\n")
 177             (with-current-buffer buffer
 178               (describe-text-properties-1 pos output-buffer))
 179             (describe-text-mode)
 180             (goto-char (point-min))))))))
 181
 182 (defun describe-text-properties-1 (pos output-buffer)
 183   (let* ((properties (text-properties-at pos))
 184          (overlays (overlays-at pos))
 185          overlay
 186          (wid-field (get-char-property pos 'field))
 187          (wid-button (get-char-property pos 'button))
 188          (wid-doc (get-char-property pos 'widget-doc))
 189          ;; If button.el is not loaded, we have no buttons in the text.
 190          (button (and (fboundp 'button-at) (button-at pos)))
 191          (button-type (and button (button-type button)))
 192          (button-label (and button (button-label button)))
 193          (widget (or wid-field wid-button wid-doc)))
 194     (with-current-buffer output-buffer
 195       ;; Widgets
 196       (when (widgetp widget)
 197         (newline)
 198         (widget-insert (cond (wid-field "This is an editable text area")
 199                              (wid-button "This is an active area")
 200                              (wid-doc "This is documentation text")))
 201         (widget-insert " of a ")
 202         (describe-text-widget widget)
 203         (widget-insert ".\n\n"))
 204       ;; Buttons
 205       (when (and button (not (widgetp wid-button)))
 206         (newline)
 207         (widget-insert "Here is a " (format "%S" button-type)
 208                        " button labeled `" button-label "'.\n\n"))
 209       ;; Overlays
 210       (when overlays
 211         (newline)
 212         (if (eq (length overlays) 1)
 213             (widget-insert "There is an overlay here:\n")
 214           (widget-insert "There are " (format "%d" (length overlays))
 215                          " overlays here:\n"))
 216         (dolist (overlay overlays)
 217           (widget-insert " From " (format "%d" (overlay-start overlay))
 218                          " to " (format "%d" (overlay-end overlay)) "\n")
 219           (describe-property-list (overlay-properties overlay)))
 220         (widget-insert "\n"))
 221       ;; Text properties
 222       (when properties
 223         (newline)
 224         (widget-insert "There are text properties here:\n")
 225         (describe-property-list properties)))))
 226 \f
 227 ;;; We cannot use the UnicodeData.txt file as such; it is not free.
 228 ;;; We can turn that info a different format and release the result
 229 ;;; as free data.  When that is done, we could reinstate the code below.
 230 ;;; For the mean time, here is a dummy placeholder.
 231 ;;;  -- rms
 232 (defun describe-char-unicode-data (char) nil)
 233
 234 ;;; (defcustom describe-char-unicodedata-file nil
 235 ;;;   "Location of Unicode data file.
 236 ;;; This is the UnicodeData.txt file from the Unicode consortium, used for
 237 ;;; diagnostics.  If it is non-nil `describe-char-after' will print data
 238 ;;; looked up from it.  This facility is mostly of use to people doing
 239 ;;; multilingual development.
 240
 241 ;;; This is a fairly large file, not typically present on GNU systems.  At
 242 ;;; the time of writing it is at
 243 ;;; <URL:ftp://www.unicode.org/Public/UNIDATA/UnicodeData.txt>."
 244 ;;;   :group 'mule
 245 ;;;   :version "21.5"
 246 ;;;   :type '(choice (const :tag "None" nil)
 247 ;;;              file))
 248
 249 ;;; ;; We could convert the unidata file into a Lispy form once-for-all
 250 ;;; ;; and distribute it for loading on demand.  It might be made more
 251 ;;; ;; space-efficient by splitting strings word-wise and replacing them
 252 ;;; ;; with lists of symbols interned in a private obarray, e.g.
 253 ;;; ;; "LATIN SMALL LETTER A" => '(LATIN SMALL LETTER A).
 254
 255 ;;; ;; Fixme: Check whether this needs updating for Unicode 4.
 256 ;;; (defun describe-char-unicode-data (char)
 257 ;;;   "Return a list of Unicode data for unicode CHAR.
 258 ;;; Each element is a list of a property description and the property value.
 259 ;;; The list is null if CHAR isn't found in `describe-char-unicodedata-file'."
 260 ;;;   (when describe-char-unicodedata-file
 261 ;;;     (unless (file-exists-p describe-char-unicodedata-file)
 262 ;;;       (error "`unicodedata-file' %s not found" describe-char-unicodedata-file))
 263 ;;;     (save-excursion
 264 ;;;       ;; Find file in fundamental mode to avoid, e.g. flyspell turned
 265 ;;;       ;; on for .txt.  Don't use RAWFILE arg in case of DOS line endings.
 266 ;;;       (set-buffer (let ((auto-mode-alist))
 267 ;;;                 (find-file-noselect describe-char-unicodedata-file)))
 268 ;;;       (goto-char (point-min))
 269 ;;;       (let ((hex (format "%04X" char))
 270 ;;;         found first last)
 271 ;;;     (if (re-search-forward (concat "^" hex) nil t)
 272 ;;;         (setq found t)
 273 ;;;       ;; It's not listed explicitly.  Look for ranges, e.g. CJK
 274 ;;;       ;; ideographs, and check whether it's in one of them.
 275 ;;;       (while (and (re-search-forward "^\\([^;]+\\);[^;]+First>;" nil t)
 276 ;;;                   (>= char (setq first
 277 ;;;                                  (string-to-number (match-string 1) 16)))
 278 ;;;                   (progn
 279 ;;;                     (forward-line 1)
 280 ;;;                     (looking-at "^\\([^;]+\\);[^;]+Last>;")
 281 ;;;                     (> char
 282 ;;;                        (setq last
 283 ;;;                              (string-to-number (match-string 1) 16))))))
 284 ;;;       (if (and (>= char first)
 285 ;;;                (<= char last))
 286 ;;;           (setq found t)))
 287 ;;;     (if found
 288 ;;;         (let ((fields (mapcar (lambda (elt)
 289 ;;;                                 (if (> (length elt) 0)
 290 ;;;                                     elt))
 291 ;;;                               (cdr (split-string
 292 ;;;                                     (buffer-substring
 293 ;;;                                      (line-beginning-position)
 294 ;;;                                      (line-end-position))
 295 ;;;                                     ";")))))
 296 ;;;           ;; The length depends on whether the last field was empty.
 297 ;;;           (unless (or (= 13 (length fields))
 298 ;;;                       (= 14 (length fields)))
 299 ;;;             (error "Invalid contents in %s" describe-char-unicodedata-file))
 300 ;;;           ;; The field names and values lists are slightly
 301 ;;;           ;; modified from Mule-UCS unidata.el.
 302 ;;;           (list
 303 ;;;            (list "Name" (let ((name (nth 0 fields)))
 304 ;;;                           ;; Check for <..., First>, <..., Last>
 305 ;;;                           (if (string-match "\\`\\(<[^,]+\\)," name)
 306 ;;;                               (concat (match-string 1 name) ">")
 307 ;;;                             name)))
 308 ;;;            (list "Category"
 309 ;;;                  (cdr (assoc
 310 ;;;                        (nth 1 fields)
 311 ;;;                        '(("Lu" . "uppercase letter")
 312 ;;;                          ("Ll" . "lowercase letter")
 313 ;;;                          ("Lt" . "titlecase letter")
 314 ;;;                          ("Mn" . "non-spacing mark")
 315 ;;;                          ("Mc" . "spacing-combining mark")
 316 ;;;                          ("Me" . "enclosing mark")
 317 ;;;                          ("Nd" . "decimal digit")
 318 ;;;                          ("Nl" . "letter number")
 319 ;;;                          ("No" . "other number")
 320 ;;;                          ("Zs" . "space separator")
 321 ;;;                          ("Zl" . "line separator")
 322 ;;;                          ("Zp" . "paragraph separator")
 323 ;;;                          ("Cc" . "other control")
 324 ;;;                          ("Cf" . "other format")
 325 ;;;                          ("Cs" . "surrogate")
 326 ;;;                          ("Co" . "private use")
 327 ;;;                          ("Cn" . "not assigned")
 328 ;;;                          ("Lm" . "modifier letter")
 329 ;;;                          ("Lo" . "other letter")
 330 ;;;                          ("Pc" . "connector punctuation")
 331 ;;;                          ("Pd" . "dash punctuation")
 332 ;;;                          ("Ps" . "open punctuation")
 333 ;;;                          ("Pe" . "close punctuation")
 334 ;;;                          ("Pi" . "initial-quotation punctuation")
 335 ;;;                          ("Pf" . "final-quotation punctuation")
 336 ;;;                          ("Po" . "other punctuation")
 337 ;;;                          ("Sm" . "math symbol")
 338 ;;;                          ("Sc" . "currency symbol")
 339 ;;;                          ("Sk" . "modifier symbol")
 340 ;;;                          ("So" . "other symbol")))))
 341 ;;;            (list "Combining class"
 342 ;;;                  (cdr (assoc
 343 ;;;                        (string-to-number (nth 2 fields))
 344 ;;;                        '((0 . "Spacing")
 345 ;;;                          (1 . "Overlays and interior")
 346 ;;;                          (7 . "Nuktas")
 347 ;;;                          (8 . "Hiragana/Katakana voicing marks")
 348 ;;;                          (9 . "Viramas")
 349 ;;;                          (10 . "Start of fixed position classes")
 350 ;;;                          (199 . "End of fixed position classes")
 351 ;;;                          (200 . "Below left attached")
 352 ;;;                          (202 . "Below attached")
 353 ;;;                          (204 . "Below right attached")
 354 ;;;                          (208 . "Left attached (reordrant around \
 355 ;;; single base character)")
 356 ;;;                          (210 . "Right attached")
 357 ;;;                          (212 . "Above left attached")
 358 ;;;                          (214 . "Above attached")
 359 ;;;                          (216 . "Above right attached")
 360 ;;;                          (218 . "Below left")
 361 ;;;                          (220 . "Below")
 362 ;;;                          (222 . "Below right")
 363 ;;;                          (224 . "Left (reordrant around single base \
 364 ;;; character)")
 365 ;;;                          (226 . "Right")
 366 ;;;                          (228 . "Above left")
 367 ;;;                          (230 . "Above")
 368 ;;;                          (232 . "Above right")
 369 ;;;                          (233 . "Double below")
 370 ;;;                          (234 . "Double above")
 371 ;;;                          (240 . "Below (iota subscript)")))))
 372 ;;;            (list "Bidi category"
 373 ;;;                  (cdr (assoc
 374 ;;;                        (nth 3 fields)
 375 ;;;                        '(("L" . "Left-to-Right")
 376 ;;;                          ("LRE" . "Left-to-Right Embedding")
 377 ;;;                          ("LRO" . "Left-to-Right Override")
 378 ;;;                          ("R" . "Right-to-Left")
 379 ;;;                          ("AL" . "Right-to-Left Arabic")
 380 ;;;                          ("RLE" . "Right-to-Left Embedding")
 381 ;;;                          ("RLO" . "Right-to-Left Override")
 382 ;;;                          ("PDF" . "Pop Directional Format")
 383 ;;;                          ("EN" . "European Number")
 384 ;;;                          ("ES" . "European Number Separator")
 385 ;;;                          ("ET" . "European Number Terminator")
 386 ;;;                          ("AN" . "Arabic Number")
 387 ;;;                          ("CS" . "Common Number Separator")
 388 ;;;                          ("NSM" . "Non-Spacing Mark")
 389 ;;;                          ("BN" . "Boundary Neutral")
 390 ;;;                          ("B" . "Paragraph Separator")
 391 ;;;                          ("S" . "Segment Separator")
 392 ;;;                          ("WS" . "Whitespace")
 393 ;;;                          ("ON" . "Other Neutrals")))))
 394 ;;;            (list
 395 ;;;             "Decomposition"
 396 ;;;             (if (nth 4 fields)
 397 ;;;                 (let* ((parts (split-string (nth 4 fields)))
 398 ;;;                        (info (car parts)))
 399 ;;;                   (if (string-match "\\`<\\(.+\\)>\\'" info)
 400 ;;;                       (setq info (match-string 1 info))
 401 ;;;                     (setq info nil))
 402 ;;;                   (if info (setq parts (cdr parts)))
 403 ;;;                   ;; Maybe printing ? for unrepresentable unicodes
 404 ;;;                   ;; here and below should be changed?
 405 ;;;                   (setq parts (mapconcat
 406 ;;;                                (lambda (arg)
 407 ;;;                                  (string (or (decode-char
 408 ;;;                                               'ucs
 409 ;;;                                               (string-to-number arg 16))
 410 ;;;                                              ??)))
 411 ;;;                                parts " "))
 412 ;;;                   (concat info parts))))
 413 ;;;            (list "Decimal digit value"
 414 ;;;                  (nth 5 fields))
 415 ;;;            (list "Digit value"
 416 ;;;                  (nth 6 fields))
 417 ;;;            (list "Numeric value"
 418 ;;;                  (nth 7 fields))
 419 ;;;            (list "Mirrored"
 420 ;;;                  (if (equal "Y" (nth 8 fields))
 421 ;;;                      "yes"))
 422 ;;;            (list "Old name" (nth 9 fields))
 423 ;;;            (list "ISO 10646 comment" (nth 10 fields))
 424 ;;;            (list "Uppercase" (and (nth 11 fields)
 425 ;;;                                   (string (or (decode-char
 426 ;;;                                                'ucs
 427 ;;;                                                (string-to-number
 428 ;;;                                                 (nth 11 fields) 16))
 429 ;;;                                               ??))))
 430 ;;;            (list "Lowercase" (and (nth 12 fields)
 431 ;;;                                   (string (or (decode-char
 432 ;;;                                                'ucs
 433 ;;;                                                (string-to-number
 434 ;;;                                                 (nth 12 fields) 16))
 435 ;;;                                               ??))))
 436 ;;;            (list "Titlecase" (and (nth 13 fields)
 437 ;;;                                   (string (or (decode-char
 438 ;;;                                                'ucs
 439 ;;;                                                (string-to-number
 440 ;;;                                                 (nth 13 fields) 16))
 441 ;;;                                               ??)))))))))))
 442
 443 ;; Return information about how CHAR is displayed at the buffer
 444 ;; position POS.  If the selected frame is on a graphic display,
 445 ;; return a cons (FONTNAME . GLYPH-CODE).  Otherwise, return a string
 446 ;; describing the terminal codes for the character.
 447 (defun describe-char-display (pos char)
 448   (if (display-graphic-p (selected-frame))
 449       (internal-char-font pos char)
 450     (let* ((coding (terminal-coding-system))
 451            (encoded (encode-coding-char char coding)))
 452       (if encoded
 453           (encoded-string-description encoded coding)))))
 454
 455 \f
 456 ;;;###autoload
 457 (defun describe-char (pos)
 458   "Describe the character after POS (interactively, the character after point).
 459 The information includes character code, charset and code points in it,
 460 syntax, category, how the character is encoded in a file,
 461 character composition information (if relevant),
 462 as well as widgets, buttons, overlays, and text properties."
 463   (interactive "d")
 464   (if (>= pos (point-max))
 465       (error "No character follows specified position"))
 466   (let* ((char (char-after pos))
 467          (charset (char-charset char))
 468          (buffer (current-buffer))
 469          (composition (find-composition pos nil nil t))
 470          (component-chars nil)
 471          (display-table (or (window-display-table)
 472                             buffer-display-table
 473                             standard-display-table))
 474          (disp-vector (and display-table (aref display-table char)))
 475          (multibyte-p enable-multibyte-characters)
 476          item-list max-width unicode)
 477     (if (eq charset 'unknown)
 478         (setq item-list
 479               `(("character"
 480                  ,(format "%s (0%o, %d, 0x%x) -- invalid character code"
 481                           (if (< char 256)
 482                               (single-key-description char)
 483                             (char-to-string char))
 484                           char char char))))
 485
 486       (if (or (< char 256)
 487               (memq 'mule-utf-8 (find-coding-systems-region pos (1+ pos)))
 488               (get-char-property pos 'untranslated-utf-8))
 489           (setq unicode (or (get-char-property pos 'untranslated-utf-8)
 490                             (encode-char char 'ucs))))
 491       (setq item-list
 492             `(("character"
 493                ,(format "%s (0%o, %d, 0x%x%s)" (if (< char 256)
 494                                                  (single-key-description char)
 495                                                (char-to-string char))
 496                         char char char
 497                         (if unicode
 498                             (format ", U+%04X" unicode)
 499                           "")))
 500               ("charset"
 501                ,(symbol-name charset)
 502                ,(format "(%s)" (charset-description charset)))
 503               ("code point"
 504                ,(let ((split (split-char char)))
 505                   (if (= (charset-dimension charset) 1)
 506                       (format "%d" (nth 1 split))
 507                     (format "%d %d" (nth 1 split) (nth 2 split)))))
 508               ("syntax"
 509                ,(let ((syntax (syntax-after pos)))
 510                   (with-temp-buffer
 511                     (internal-describe-syntax-value syntax)
 512                     (buffer-string))))
 513               ("category"
 514                ,@(let ((category-set (char-category-set char)))
 515                    (if (not category-set)
 516                        '("-- none --")
 517                      (mapcar #'(lambda (x) (format "%c:%s  "
 518                                                    x (category-docstring x)))
 519                              (category-set-mnemonics category-set)))))
 520               ,@(let ((props (aref char-code-property-table char))
 521                       ps)
 522                   (when props
 523                     (while props
 524                       (push (format "%s:" (pop props)) ps)
 525                       (push (format "%s;" (pop props)) ps))
 526                     (list (cons "Properties" (nreverse ps)))))
 527               ("buffer code"
 528                ,(encoded-string-description
 529                  (string-as-unibyte (char-to-string char)) nil))
 530               ("file code"
 531                ,@(let* ((coding buffer-file-coding-system)
 532                         (encoded (encode-coding-char char coding)))
 533                    (if encoded
 534                        (list (encoded-string-description encoded coding)
 535                              (format "(encoded by coding system %S)" coding))
 536                      (list "not encodable by coding system"
 537                            (symbol-name coding)))))
 538               ("display"
 539                ,(cond
 540                  (disp-vector
 541                   (setq disp-vector (copy-sequence disp-vector))
 542                   (dotimes (i (length disp-vector))
 543                     (setq char (aref disp-vector i))
 544                     (aset disp-vector i
 545                           (cons char (describe-char-display pos char))))
 546                   (format "by display table entry [%s] (see below)"
 547                           (mapconcat #'(lambda (x) (format "?%c" (car x)))
 548                                      disp-vector " ")))
 549                  (composition
 550                   (let ((from (car composition))
 551                         (to (nth 1 composition))
 552                         (next (1+ pos))
 553                         (components (nth 2 composition))
 554                         ch)
 555                     (setcar composition
 556                             (and (< from pos) (buffer-substring from pos)))
 557                     (setcar (cdr composition)
 558                             (and (< next to) (buffer-substring next to)))
 559                     (dotimes (i (length components))
 560                       (if (integerp (setq ch (aref components i)))
 561                           (push (cons ch (describe-char-display pos ch))
 562                                 component-chars)))
 563                     (setq component-chars (nreverse component-chars))
 564                     (format "composed to form \"%s\" (see below)"
 565                             (buffer-substring from to))))
 566                  (t
 567                   (let ((display (describe-char-display pos char)))
 568                     (if (display-graphic-p (selected-frame))
 569                         (if display
 570                             (concat
 571                              "by this font (glyph code)\n"
 572                              (format "     %s (0x%02X)"
 573                                      (car display) (cdr display)))
 574                           "no font available")
 575                       (if display
 576                           (format "terminal code %s" display)
 577                         "not encodable for terminal"))))))
 578               ,@(let ((unicodedata (and unicode
 579                                         (describe-char-unicode-data unicode))))
 580                   (if unicodedata
 581                       (cons (list "Unicode data" " ") unicodedata))))))
 582     (setq max-width (apply #'max (mapcar #'(lambda (x) (length (car x)))
 583                                          item-list)))
 584     (when (eq (current-buffer) (get-buffer "*Help*"))
 585       (error "Can't describe char in Help buffer"))
 586     (with-output-to-temp-buffer "*Help*"
 587       (with-current-buffer standard-output
 588         (set-buffer-multibyte multibyte-p)
 589         (let ((formatter (format "%%%ds:" max-width)))
 590           (dolist (elt item-list)
 591             (when (cadr elt)
 592               (insert (format formatter (car elt)))
 593               (dolist (clm (cdr elt))
 594                 (when (>= (+ (current-column)
 595                              (or (string-match "\n" clm)
 596                                  (string-width clm)) 1)
 597                           (window-width))
 598                   (insert "\n")
 599                   (indent-to (1+ max-width)))
 600                 (insert " " clm))
 601               (insert "\n"))))
 602
 603         (when disp-vector
 604           (insert
 605            "\nThe display table entry is displayed by ")
 606           (if (display-graphic-p (selected-frame))
 607               (progn
 608                 (insert "these fonts (glyph codes):\n")
 609                 (dotimes (i (length disp-vector))
 610                   (insert (car (aref disp-vector i)) ?:
 611                           (propertize " " 'display '(space :align-to 5))
 612                           (if (cdr (aref disp-vector i))
 613                               (format "%s (0x%02X)" (cadr (aref disp-vector i))
 614                                       (cddr (aref disp-vector i)))
 615                             "-- no font --")
 616                           "\n ")))
 617             (insert "these terminal codes:\n")
 618             (dotimes (i (length disp-vector))
 619               (insert (car (aref disp-vector i))
 620                       (propertize " " 'display '(space :align-to 5))
 621                       (or (cdr (aref disp-vector i)) "-- not encodable --")
 622                       "\n"))))
 623
 624         (when composition
 625           (insert "\nComposed")
 626           (if (car composition)
 627               (if (cadr composition)
 628                   (insert " with the surrounding characters \""
 629                           (car composition) "\" and \""
 630                           (cadr composition) "\"")
 631                 (insert " with the preceding character(s) \""
 632                         (car composition) "\""))
 633             (if (cadr composition)
 634                 (insert " with the following character(s) \""
 635                         (cadr composition) "\"")))
 636           (insert " by the rule:\n\t("
 637                   (mapconcat (lambda (x)
 638                                (format (if (consp x) "%S" "?%c") x))
 639                              (nth 2 composition)
 640                              " ")
 641                   ")")
 642           (insert  "\nThe component character(s) are displayed by ")
 643           (if (display-graphic-p (selected-frame))
 644               (progn
 645                 (insert "these fonts (glyph codes):")
 646                 (dolist (elt component-chars)
 647                   (insert "\n " (car elt) ?:
 648                           (propertize " " 'display '(space :align-to 5))
 649                           (if (cdr elt)
 650                               (format "%s (0x%02X)" (cadr elt) (cddr elt))
 651                             "-- no font --"))))
 652             (insert "these terminal codes:")
 653             (dolist (elt component-chars)
 654               (insert "\n  " (car elt) ":"
 655                       (propertize " " 'display '(space :align-to 5))
 656                       (or (cdr elt) "-- not encodable --"))))
 657           (insert "\nSee the variable `reference-point-alist' for "
 658                   "the meaning of the rule.\n"))
 659
 660         (let ((output (current-buffer)))
 661           (with-current-buffer buffer
 662             (describe-text-properties pos output))
 663           (describe-text-mode))))))
 664
 665 (defalias 'describe-char-after 'describe-char)
 666 (make-obsolete 'describe-char-after 'describe-char "21.5")
 667
 668 (provide 'descr-text)
 669
 670 ;;; arch-tag: fc55a498-f3e9-4312-b5bd-98cc02480af1
 671 ;;; descr-text.el ends here