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', `face' and `font-lock-face' properties are made
 103 into widget buttons that call `describe-text-category' or
 104 `describe-face' when pushed."
 105   ;; Sort the properties by the size of their value.
 106   (dolist (elt (sort (let ((ret nil)
 107                            (key nil)
 108                            (val nil)
 109                            (len nil))
 110                        (while properties
 111                          (setq key (pop properties)
 112                                val (pop properties)
 113                                len 0)
 114                          (unless (or (memq key '(category face font-lock-face))
 115                                      (widgetp val))
 116                            (setq val (pp-to-string val)
 117                                  len (length val)))
 118                          (push (list key val len) ret))
 119                        ret)
 120                      (lambda (a b)
 121                        (< (nth 2 a)
 122                           (nth 2 b)))))
 123     (let ((key (nth 0 elt))
 124           (value (nth 1 elt)))
 125       (widget-insert (propertize (format "  %-20s " key)
 126                                  'font-lock-face 'italic))
 127       (cond ((eq key 'category)
 128              (widget-create 'link
 129                             :notify `(lambda (&rest ignore)
 130                                        (describe-text-category ',value))
 131                             (format "%S" value)))
 132             ((memq key '(face font-lock-face))
 133              (widget-create 'link
 134                             :notify `(lambda (&rest ignore)
 135                                        (describe-face ',value))
 136                             (format "%S" value)))
 137             ((widgetp value)
 138              (describe-text-widget value))
 139             (t
 140              (widget-insert value))))
 141     (widget-insert "\n")))
 142 \f
 143 ;;; Describe-Text Commands.
 144
 145 (defun describe-text-category (category)
 146   "Describe a text property category."
 147   (interactive "S")
 148   (save-excursion
 149     (with-output-to-temp-buffer "*Help*"
 150       (set-buffer standard-output)
 151       (widget-insert "Category " (format "%S" category) ":\n\n")
 152       (describe-property-list (symbol-plist category))
 153       (describe-text-mode)
 154       (goto-char (point-min)))))
 155
 156 ;;;###autoload
 157 (defun describe-text-properties (pos &optional output-buffer)
 158   "Describe widgets, buttons, overlays and text properties at POS.
 159 Interactively, describe them for the character after point.
 160 If optional second argument OUTPUT-BUFFER is non-nil,
 161 insert the output into that buffer, and don't initialize or clear it
 162 otherwise."
 163   (interactive "d")
 164   (if (>= pos (point-max))
 165       (error "No character follows specified position"))
 166   (if output-buffer
 167       (describe-text-properties-1 pos output-buffer)
 168     (if (not (or (text-properties-at pos) (overlays-at pos)))
 169         (message "This is plain text.")
 170       (let ((buffer (current-buffer)))
 171         (when (eq buffer (get-buffer "*Help*"))
 172           (error "Can't do self inspection"))
 173         (save-excursion
 174           (with-output-to-temp-buffer "*Help*"
 175             (set-buffer standard-output)
 176             (setq output-buffer (current-buffer))
 177             (widget-insert "Text content at position " (format "%d" pos) ":\n\n")
 178             (with-current-buffer buffer
 179               (describe-text-properties-1 pos output-buffer))
 180             (describe-text-mode)
 181             (goto-char (point-min))))))))
 182
 183 (defun describe-text-properties-1 (pos output-buffer)
 184   (let* ((properties (text-properties-at pos))
 185          (overlays (overlays-at pos))
 186          overlay
 187          (wid-field (get-char-property pos 'field))
 188          (wid-button (get-char-property pos 'button))
 189          (wid-doc (get-char-property pos 'widget-doc))
 190          ;; If button.el is not loaded, we have no buttons in the text.
 191          (button (and (fboundp 'button-at) (button-at pos)))
 192          (button-type (and button (button-type button)))
 193          (button-label (and button (button-label button)))
 194          (widget (or wid-field wid-button wid-doc)))
 195     (with-current-buffer output-buffer
 196       ;; Widgets
 197       (when (widgetp widget)
 198         (newline)
 199         (widget-insert (cond (wid-field "This is an editable text area")
 200                              (wid-button "This is an active area")
 201                              (wid-doc "This is documentation text")))
 202         (widget-insert " of a ")
 203         (describe-text-widget widget)
 204         (widget-insert ".\n\n"))
 205       ;; Buttons
 206       (when (and button (not (widgetp wid-button)))
 207         (newline)
 208         (widget-insert "Here is a " (format "%S" button-type)
 209                        " button labeled `" button-label "'.\n\n"))
 210       ;; Overlays
 211       (when overlays
 212         (newline)
 213         (if (eq (length overlays) 1)
 214             (widget-insert "There is an overlay here:\n")
 215           (widget-insert "There are " (format "%d" (length overlays))
 216                          " overlays here:\n"))
 217         (dolist (overlay overlays)
 218           (widget-insert " From " (format "%d" (overlay-start overlay))
 219                          " to " (format "%d" (overlay-end overlay)) "\n")
 220           (describe-property-list (overlay-properties overlay)))
 221         (widget-insert "\n"))
 222       ;; Text properties
 223       (when properties
 224         (newline)
 225         (widget-insert "There are text properties here:\n")
 226         (describe-property-list properties)))))
 227 \f
 228 ;;; We cannot use the UnicodeData.txt file as such; it is not free.
 229 ;;; We can turn that info a different format and release the result
 230 ;;; as free data.  When that is done, we could reinstate the code below.
 231 ;;; For the mean time, here is a dummy placeholder.
 232 ;;;  -- rms
 233 (defun describe-char-unicode-data (char) nil)
 234
 235 ;;; (defcustom describe-char-unicodedata-file nil
 236 ;;;   "Location of Unicode data file.
 237 ;;; This is the UnicodeData.txt file from the Unicode consortium, used for
 238 ;;; diagnostics.  If it is non-nil `describe-char-after' will print data
 239 ;;; looked up from it.  This facility is mostly of use to people doing
 240 ;;; multilingual development.
 241
 242 ;;; This is a fairly large file, not typically present on GNU systems.  At
 243 ;;; the time of writing it is at
 244 ;;; <URL:ftp://www.unicode.org/Public/UNIDATA/UnicodeData.txt>."
 245 ;;;   :group 'mule
 246 ;;;   :version "21.5"
 247 ;;;   :type '(choice (const :tag "None" nil)
 248 ;;;              file))
 249
 250 ;;; ;; We could convert the unidata file into a Lispy form once-for-all
 251 ;;; ;; and distribute it for loading on demand.  It might be made more
 252 ;;; ;; space-efficient by splitting strings word-wise and replacing them
 253 ;;; ;; with lists of symbols interned in a private obarray, e.g.
 254 ;;; ;; "LATIN SMALL LETTER A" => '(LATIN SMALL LETTER A).
 255
 256 ;;; ;; Fixme: Check whether this needs updating for Unicode 4.
 257 ;;; (defun describe-char-unicode-data (char)
 258 ;;;   "Return a list of Unicode data for unicode CHAR.
 259 ;;; Each element is a list of a property description and the property value.
 260 ;;; The list is null if CHAR isn't found in `describe-char-unicodedata-file'."
 261 ;;;   (when describe-char-unicodedata-file
 262 ;;;     (unless (file-exists-p describe-char-unicodedata-file)
 263 ;;;       (error "`unicodedata-file' %s not found" describe-char-unicodedata-file))
 264 ;;;     (save-excursion
 265 ;;;       ;; Find file in fundamental mode to avoid, e.g. flyspell turned
 266 ;;;       ;; on for .txt.  Don't use RAWFILE arg in case of DOS line endings.
 267 ;;;       (set-buffer (let ((auto-mode-alist))
 268 ;;;                 (find-file-noselect describe-char-unicodedata-file)))
 269 ;;;       (goto-char (point-min))
 270 ;;;       (let ((hex (format "%04X" char))
 271 ;;;         found first last)
 272 ;;;     (if (re-search-forward (concat "^" hex) nil t)
 273 ;;;         (setq found t)
 274 ;;;       ;; It's not listed explicitly.  Look for ranges, e.g. CJK
 275 ;;;       ;; ideographs, and check whether it's in one of them.
 276 ;;;       (while (and (re-search-forward "^\\([^;]+\\);[^;]+First>;" nil t)
 277 ;;;                   (>= char (setq first
 278 ;;;                                  (string-to-number (match-string 1) 16)))
 279 ;;;                   (progn
 280 ;;;                     (forward-line 1)
 281 ;;;                     (looking-at "^\\([^;]+\\);[^;]+Last>;")
 282 ;;;                     (> char
 283 ;;;                        (setq last
 284 ;;;                              (string-to-number (match-string 1) 16))))))
 285 ;;;       (if (and (>= char first)
 286 ;;;                (<= char last))
 287 ;;;           (setq found t)))
 288 ;;;     (if found
 289 ;;;         (let ((fields (mapcar (lambda (elt)
 290 ;;;                                 (if (> (length elt) 0)
 291 ;;;                                     elt))
 292 ;;;                               (cdr (split-string
 293 ;;;                                     (buffer-substring
 294 ;;;                                      (line-beginning-position)
 295 ;;;                                      (line-end-position))
 296 ;;;                                     ";")))))
 297 ;;;           ;; The length depends on whether the last field was empty.
 298 ;;;           (unless (or (= 13 (length fields))
 299 ;;;                       (= 14 (length fields)))
 300 ;;;             (error "Invalid contents in %s" describe-char-unicodedata-file))
 301 ;;;           ;; The field names and values lists are slightly
 302 ;;;           ;; modified from Mule-UCS unidata.el.
 303 ;;;           (list
 304 ;;;            (list "Name" (let ((name (nth 0 fields)))
 305 ;;;                           ;; Check for <..., First>, <..., Last>
 306 ;;;                           (if (string-match "\\`\\(<[^,]+\\)," name)
 307 ;;;                               (concat (match-string 1 name) ">")
 308 ;;;                             name)))
 309 ;;;            (list "Category"
 310 ;;;                  (cdr (assoc
 311 ;;;                        (nth 1 fields)
 312 ;;;                        '(("Lu" . "uppercase letter")
 313 ;;;                          ("Ll" . "lowercase letter")
 314 ;;;                          ("Lt" . "titlecase letter")
 315 ;;;                          ("Mn" . "non-spacing mark")
 316 ;;;                          ("Mc" . "spacing-combining mark")
 317 ;;;                          ("Me" . "enclosing mark")
 318 ;;;                          ("Nd" . "decimal digit")
 319 ;;;                          ("Nl" . "letter number")
 320 ;;;                          ("No" . "other number")
 321 ;;;                          ("Zs" . "space separator")
 322 ;;;                          ("Zl" . "line separator")
 323 ;;;                          ("Zp" . "paragraph separator")
 324 ;;;                          ("Cc" . "other control")
 325 ;;;                          ("Cf" . "other format")
 326 ;;;                          ("Cs" . "surrogate")
 327 ;;;                          ("Co" . "private use")
 328 ;;;                          ("Cn" . "not assigned")
 329 ;;;                          ("Lm" . "modifier letter")
 330 ;;;                          ("Lo" . "other letter")
 331 ;;;                          ("Pc" . "connector punctuation")
 332 ;;;                          ("Pd" . "dash punctuation")
 333 ;;;                          ("Ps" . "open punctuation")
 334 ;;;                          ("Pe" . "close punctuation")
 335 ;;;                          ("Pi" . "initial-quotation punctuation")
 336 ;;;                          ("Pf" . "final-quotation punctuation")
 337 ;;;                          ("Po" . "other punctuation")
 338 ;;;                          ("Sm" . "math symbol")
 339 ;;;                          ("Sc" . "currency symbol")
 340 ;;;                          ("Sk" . "modifier symbol")
 341 ;;;                          ("So" . "other symbol")))))
 342 ;;;            (list "Combining class"
 343 ;;;                  (cdr (assoc
 344 ;;;                        (string-to-number (nth 2 fields))
 345 ;;;                        '((0 . "Spacing")
 346 ;;;                          (1 . "Overlays and interior")
 347 ;;;                          (7 . "Nuktas")
 348 ;;;                          (8 . "Hiragana/Katakana voicing marks")
 349 ;;;                          (9 . "Viramas")
 350 ;;;                          (10 . "Start of fixed position classes")
 351 ;;;                          (199 . "End of fixed position classes")
 352 ;;;                          (200 . "Below left attached")
 353 ;;;                          (202 . "Below attached")
 354 ;;;                          (204 . "Below right attached")
 355 ;;;                          (208 . "Left attached (reordrant around \
 356 ;;; single base character)")
 357 ;;;                          (210 . "Right attached")
 358 ;;;                          (212 . "Above left attached")
 359 ;;;                          (214 . "Above attached")
 360 ;;;                          (216 . "Above right attached")
 361 ;;;                          (218 . "Below left")
 362 ;;;                          (220 . "Below")
 363 ;;;                          (222 . "Below right")
 364 ;;;                          (224 . "Left (reordrant around single base \
 365 ;;; character)")
 366 ;;;                          (226 . "Right")
 367 ;;;                          (228 . "Above left")
 368 ;;;                          (230 . "Above")
 369 ;;;                          (232 . "Above right")
 370 ;;;                          (233 . "Double below")
 371 ;;;                          (234 . "Double above")
 372 ;;;                          (240 . "Below (iota subscript)")))))
 373 ;;;            (list "Bidi category"
 374 ;;;                  (cdr (assoc
 375 ;;;                        (nth 3 fields)
 376 ;;;                        '(("L" . "Left-to-Right")
 377 ;;;                          ("LRE" . "Left-to-Right Embedding")
 378 ;;;                          ("LRO" . "Left-to-Right Override")
 379 ;;;                          ("R" . "Right-to-Left")
 380 ;;;                          ("AL" . "Right-to-Left Arabic")
 381 ;;;                          ("RLE" . "Right-to-Left Embedding")
 382 ;;;                          ("RLO" . "Right-to-Left Override")
 383 ;;;                          ("PDF" . "Pop Directional Format")
 384 ;;;                          ("EN" . "European Number")
 385 ;;;                          ("ES" . "European Number Separator")
 386 ;;;                          ("ET" . "European Number Terminator")
 387 ;;;                          ("AN" . "Arabic Number")
 388 ;;;                          ("CS" . "Common Number Separator")
 389 ;;;                          ("NSM" . "Non-Spacing Mark")
 390 ;;;                          ("BN" . "Boundary Neutral")
 391 ;;;                          ("B" . "Paragraph Separator")
 392 ;;;                          ("S" . "Segment Separator")
 393 ;;;                          ("WS" . "Whitespace")
 394 ;;;                          ("ON" . "Other Neutrals")))))
 395 ;;;            (list
 396 ;;;             "Decomposition"
 397 ;;;             (if (nth 4 fields)
 398 ;;;                 (let* ((parts (split-string (nth 4 fields)))
 399 ;;;                        (info (car parts)))
 400 ;;;                   (if (string-match "\\`<\\(.+\\)>\\'" info)
 401 ;;;                       (setq info (match-string 1 info))
 402 ;;;                     (setq info nil))
 403 ;;;                   (if info (setq parts (cdr parts)))
 404 ;;;                   ;; Maybe printing ? for unrepresentable unicodes
 405 ;;;                   ;; here and below should be changed?
 406 ;;;                   (setq parts (mapconcat
 407 ;;;                                (lambda (arg)
 408 ;;;                                  (string (or (decode-char
 409 ;;;                                               'ucs
 410 ;;;                                               (string-to-number arg 16))
 411 ;;;                                              ??)))
 412 ;;;                                parts " "))
 413 ;;;                   (concat info parts))))
 414 ;;;            (list "Decimal digit value"
 415 ;;;                  (nth 5 fields))
 416 ;;;            (list "Digit value"
 417 ;;;                  (nth 6 fields))
 418 ;;;            (list "Numeric value"
 419 ;;;                  (nth 7 fields))
 420 ;;;            (list "Mirrored"
 421 ;;;                  (if (equal "Y" (nth 8 fields))
 422 ;;;                      "yes"))
 423 ;;;            (list "Old name" (nth 9 fields))
 424 ;;;            (list "ISO 10646 comment" (nth 10 fields))
 425 ;;;            (list "Uppercase" (and (nth 11 fields)
 426 ;;;                                   (string (or (decode-char
 427 ;;;                                                'ucs
 428 ;;;                                                (string-to-number
 429 ;;;                                                 (nth 11 fields) 16))
 430 ;;;                                               ??))))
 431 ;;;            (list "Lowercase" (and (nth 12 fields)
 432 ;;;                                   (string (or (decode-char
 433 ;;;                                                'ucs
 434 ;;;                                                (string-to-number
 435 ;;;                                                 (nth 12 fields) 16))
 436 ;;;                                               ??))))
 437 ;;;            (list "Titlecase" (and (nth 13 fields)
 438 ;;;                                   (string (or (decode-char
 439 ;;;                                                'ucs
 440 ;;;                                                (string-to-number
 441 ;;;                                                 (nth 13 fields) 16))
 442 ;;;                                               ??)))))))))))
 443
 444 ;; Return information about how CHAR is displayed at the buffer
 445 ;; position POS.  If the selected frame is on a graphic display,
 446 ;; return a cons (FONTNAME . GLYPH-CODE).  Otherwise, return a string
 447 ;; describing the terminal codes for the character.
 448 (defun describe-char-display (pos char)
 449   (if (display-graphic-p (selected-frame))
 450       (internal-char-font pos char)
 451     (let* ((coding (terminal-coding-system))
 452            (encoded (encode-coding-char char coding)))
 453       (if encoded
 454           (encoded-string-description encoded coding)))))
 455
 456 \f
 457 ;;;###autoload
 458 (defun describe-char (pos)
 459   "Describe the character after POS (interactively, the character after point).
 460 The information includes character code, charset and code points in it,
 461 syntax, category, how the character is encoded in a file,
 462 character composition information (if relevant),
 463 as well as widgets, buttons, overlays, and text properties."
 464   (interactive "d")
 465   (if (>= pos (point-max))
 466       (error "No character follows specified position"))
 467   (let* ((char (char-after pos))
 468          (charset (char-charset char))
 469          (buffer (current-buffer))
 470          (composition (find-composition pos nil nil t))
 471          (component-chars nil)
 472          (display-table (or (window-display-table)
 473                             buffer-display-table
 474                             standard-display-table))
 475          (disp-vector (and display-table (aref display-table char)))
 476          (multibyte-p enable-multibyte-characters)
 477          text-prop-description
 478          item-list max-width unicode)
 479     (if (eq charset 'unknown)
 480         (setq item-list
 481               `(("character"
 482                  ,(format "%s (0%o, %d, 0x%x) -- invalid character code"
 483                           (if (< char 256)
 484                               (single-key-description char)
 485                             (char-to-string char))
 486                           char char char))))
 487
 488       (if (or (< char 256)
 489               (memq 'mule-utf-8 (find-coding-systems-region pos (1+ pos)))
 490               (get-char-property pos 'untranslated-utf-8))
 491           (setq unicode (or (get-char-property pos 'untranslated-utf-8)
 492                             (encode-char char 'ucs))))
 493       (setq item-list
 494             `(("character"
 495                ,(format "%s (0%o, %d, 0x%x%s)" (if (< char 256)
 496                                                  (single-key-description char)
 497                                                (char-to-string char))
 498                         char char char
 499                         (if unicode
 500                             (format ", U+%04X" unicode)
 501                           "")))
 502               ("charset"
 503                ,(symbol-name charset)
 504                ,(format "(%s)" (charset-description charset)))
 505               ("code point"
 506                ,(let ((split (split-char char)))
 507                   (if (= (charset-dimension charset) 1)
 508                       (format "%d" (nth 1 split))
 509                     (format "%d %d" (nth 1 split) (nth 2 split)))))
 510               ("syntax"
 511                ,(let ((syntax (syntax-after pos)))
 512                   (with-temp-buffer
 513                     (internal-describe-syntax-value syntax)
 514                     (buffer-string))))
 515               ("category"
 516                ,@(let ((category-set (char-category-set char)))
 517                    (if (not category-set)
 518                        '("-- none --")
 519                      (mapcar #'(lambda (x) (format "%c:%s  "
 520                                                    x (category-docstring x)))
 521                              (category-set-mnemonics category-set)))))
 522               ,@(let ((props (aref char-code-property-table char))
 523                       ps)
 524                   (when props
 525                     (while props
 526                       (push (format "%s:" (pop props)) ps)
 527                       (push (format "%s;" (pop props)) ps))
 528                     (list (cons "Properties" (nreverse ps)))))
 529               ("buffer code"
 530                ,(encoded-string-description
 531                  (string-as-unibyte (char-to-string char)) nil))
 532               ("file code"
 533                ,@(let* ((coding buffer-file-coding-system)
 534                         (encoded (encode-coding-char char coding)))
 535                    (if encoded
 536                        (list (encoded-string-description encoded coding)
 537                              (format "(encoded by coding system %S)" coding))
 538                      (list "not encodable by coding system"
 539                            (symbol-name coding)))))
 540               ("display"
 541                ,(cond
 542                  (disp-vector
 543                   (setq disp-vector (copy-sequence disp-vector))
 544                   (dotimes (i (length disp-vector))
 545                     (setq char (aref disp-vector i))
 546                     (aset disp-vector i
 547                           (cons char (describe-char-display pos char))))
 548                   (format "by display table entry [%s] (see below)"
 549                           (mapconcat #'(lambda (x) (format "?%c" (car x)))
 550                                      disp-vector " ")))
 551                  (composition
 552                   (let ((from (car composition))
 553                         (to (nth 1 composition))
 554                         (next (1+ pos))
 555                         (components (nth 2 composition))
 556                         ch)
 557                     (setcar composition
 558                             (and (< from pos) (buffer-substring from pos)))
 559                     (setcar (cdr composition)
 560                             (and (< next to) (buffer-substring next to)))
 561                     (dotimes (i (length components))
 562                       (if (integerp (setq ch (aref components i)))
 563                           (push (cons ch (describe-char-display pos ch))
 564                                 component-chars)))
 565                     (setq component-chars (nreverse component-chars))
 566                     (format "composed to form \"%s\" (see below)"
 567                             (buffer-substring from to))))
 568                  (t
 569                   (let ((display (describe-char-display pos char)))
 570                     (if (display-graphic-p (selected-frame))
 571                         (if display
 572                             (concat
 573                              "by this font (glyph code)\n"
 574                              (format "     %s (0x%02X)"
 575                                      (car display) (cdr display)))
 576                           "no font available")
 577                       (if display
 578                           (format "terminal code %s" display)
 579                         "not encodable for terminal"))))))
 580               ,@(let ((unicodedata (and unicode
 581                                         (describe-char-unicode-data unicode))))
 582                   (if unicodedata
 583                       (cons (list "Unicode data" " ") unicodedata))))))
 584     (setq max-width (apply #'max (mapcar #'(lambda (x) (length (car x)))
 585                                          item-list)))
 586     (setq text-prop-description
 587           (with-temp-buffer
 588             (let ((buf (current-buffer)))
 589               (save-excursion
 590                 (set-buffer buffer)
 591                 (describe-text-properties pos buf)))
 592             (buffer-string)))
 593
 594     (with-output-to-temp-buffer "*Help*"
 595       (with-current-buffer standard-output
 596         (set-buffer-multibyte multibyte-p)
 597         (let ((formatter (format "%%%ds:" max-width)))
 598           (dolist (elt item-list)
 599             (when (cadr elt)
 600               (insert (format formatter (car elt)))
 601               (dolist (clm (cdr elt))
 602                 (when (>= (+ (current-column)
 603                              (or (string-match "\n" clm)
 604                                  (string-width clm)) 1)
 605                           (window-width))
 606                   (insert "\n")
 607                   (indent-to (1+ max-width)))
 608                 (insert " " clm))
 609               (insert "\n"))))
 610
 611         (when disp-vector
 612           (insert
 613            "\nThe display table entry is displayed by ")
 614           (if (display-graphic-p (selected-frame))
 615               (progn
 616                 (insert "these fonts (glyph codes):\n")
 617                 (dotimes (i (length disp-vector))
 618                   (insert (car (aref disp-vector i)) ?:
 619                           (propertize " " 'display '(space :align-to 5))
 620                           (if (cdr (aref disp-vector i))
 621                               (format "%s (0x%02X)" (cadr (aref disp-vector i))
 622                                       (cddr (aref disp-vector i)))
 623                             "-- no font --")
 624                           "\n ")))
 625             (insert "these terminal codes:\n")
 626             (dotimes (i (length disp-vector))
 627               (insert (car (aref disp-vector i))
 628                       (propertize " " 'display '(space :align-to 5))
 629                       (or (cdr (aref disp-vector i)) "-- not encodable --")
 630                       "\n"))))
 631
 632         (when composition
 633           (insert "\nComposed")
 634           (if (car composition)
 635               (if (cadr composition)
 636                   (insert " with the surrounding characters \""
 637                           (car composition) "\" and \""
 638                           (cadr composition) "\"")
 639                 (insert " with the preceding character(s) \""
 640                         (car composition) "\""))
 641             (if (cadr composition)
 642                 (insert " with the following character(s) \""
 643                         (cadr composition) "\"")))
 644           (insert " by the rule:\n\t("
 645                   (mapconcat (lambda (x)
 646                                (format (if (consp x) "%S" "?%c") x))
 647                              (nth 2 composition)
 648                              " ")
 649                   ")")
 650           (insert  "\nThe component character(s) are displayed by ")
 651           (if (display-graphic-p (selected-frame))
 652               (progn
 653                 (insert "these fonts (glyph codes):")
 654                 (dolist (elt component-chars)
 655                   (insert "\n " (car elt) ?:
 656                           (propertize " " 'display '(space :align-to 5))
 657                           (if (cdr elt)
 658                               (format "%s (0x%02X)" (cadr elt) (cddr elt))
 659                             "-- no font --"))))
 660             (insert "these terminal codes:")
 661             (dolist (elt component-chars)
 662               (insert "\n  " (car elt) ":"
 663                       (propertize " " 'display '(space :align-to 5))
 664                       (or (cdr elt) "-- not encodable --"))))
 665           (insert "\nSee the variable `reference-point-alist' for "
 666                   "the meaning of the rule.\n"))
 667
 668         (insert text-prop-description)
 669         (describe-text-mode)))))
 670
 671 (defalias 'describe-char-after 'describe-char)
 672 (make-obsolete 'describe-char-after 'describe-char "21.5")
 673
 674 (provide 'descr-text)
 675
 676 ;;; arch-tag: fc55a498-f3e9-4312-b5bd-98cc02480af1
 677 ;;; descr-text.el ends here