lisp/descr-text.el

   1 ;;; descr-text.el --- describe text mode  -*- lexical-binding:t -*-
   2
   3 ;; Copyright (C) 1994-1996, 2001-2015 Free Software Foundation, Inc.
   4
   5 ;; Author: Boris Goldowsky <boris@gnu.org>
   6 ;; Maintainer: emacs-devel@gnu.org
   7 ;; Keywords: faces, i18n, Unicode, multilingual
   8
   9 ;; This file is part of GNU Emacs.
  10
  11 ;; GNU Emacs is free software: you can redistribute it and/or modify
  12 ;; it under the terms of the GNU General Public License as published by
  13 ;; the Free Software Foundation, either version 3 of the License, or
  14 ;; (at your option) any later version.
  15
  16 ;; GNU Emacs is distributed in the hope that it will be useful,
  17 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  18 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19 ;; GNU General Public License for more details.
  20
  21 ;; You should have received a copy of the GNU General Public License
  22 ;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
  23
  24 ;;; Commentary:
  25
  26 ;; Describe-Text Mode.
  27
  28 ;;; Code:
  29
  30 (eval-when-compile (require 'quail))
  31 (require 'help-mode)
  32
  33 ;;; Describe-Text Utilities.
  34
  35 (defun describe-text-widget (widget)
  36   "Insert text to describe WIDGET in the current buffer."
  37   (insert-text-button
  38    (symbol-name (if (symbolp widget) widget (car widget)))
  39    'action (lambda (&rest _ignore) (widget-browse widget))
  40    'help-echo "mouse-2, RET: browse this widget")
  41   (insert " ")
  42   (insert-text-button
  43    "(widget)Top" 'type 'help-info 'help-args '("(widget)Top")))
  44
  45 (defun describe-text-sexp (sexp)
  46   "Insert a short description of SEXP in the current buffer."
  47   (let ((pp (condition-case signal
  48                 (pp-to-string sexp)
  49               (error (prin1-to-string signal)))))
  50     (when (string-match-p "\n\\'" pp)
  51       (setq pp (substring pp 0 (1- (length pp)))))
  52
  53     (if (and (not (string-match-p "\n" pp))
  54              (<= (length pp) (- (window-width) (current-column))))
  55         (insert pp)
  56       (insert-text-button
  57        "[Show]" 'action (lambda (&rest _ignore)
  58                           (with-output-to-temp-buffer
  59                               "*Pp Eval Output*"
  60                             (princ pp)))
  61        'help-echo "mouse-2, RET: pretty print value in another buffer"))))
  62
  63 (defun describe-property-list (properties)
  64   "Insert a description of PROPERTIES in the current buffer.
  65 PROPERTIES should be a list of overlay or text properties.
  66 The `category', `face' and `font-lock-face' properties are made
  67 into help buttons that call `describe-text-category' or
  68 `describe-face' when pushed."
  69   ;; Sort the properties by the size of their value.
  70   (dolist (elt (sort (let (ret)
  71                        (while properties
  72                          (push (list (pop properties) (pop properties)) ret))
  73                        ret)
  74                      (lambda (a b) (string< (prin1-to-string (nth 0 a) t)
  75                                             (prin1-to-string (nth 0 b) t)))))
  76     (let ((key (nth 0 elt))
  77           (value (nth 1 elt)))
  78       (insert (propertize (format "  %-20s " key)
  79                           'face 'help-argument-name))
  80       (cond ((eq key 'category)
  81              (insert-text-button
  82               (symbol-name value)
  83               'action (lambda (&rest _ignore)
  84                         (describe-text-category value))
  85               'follow-link t
  86               'help-echo "mouse-2, RET: describe this category"))
  87             ((memq key '(face font-lock-face mouse-face))
  88              (insert-text-button
  89               (format "%S" value)
  90               'type 'help-face 'help-args (list value)))
  91             ((widgetp value)
  92              (describe-text-widget value))
  93             (t
  94              (describe-text-sexp value))))
  95     (insert "\n")))
  96 \f
  97 ;;; Describe-Text Commands.
  98
  99 (defun describe-text-category (category)
 100   "Describe a text property category."
 101   (interactive "SCategory: ")
 102   (help-setup-xref (list #'describe-text-category category)
 103                    (called-interactively-p 'interactive))
 104   (with-help-window (help-buffer)
 105     (with-current-buffer standard-output
 106       (insert "Category " (format "%S" category) ":\n\n")
 107       (describe-property-list (symbol-plist category))
 108       (goto-char (point-min)))))
 109
 110 ;;;###autoload
 111 (defun describe-text-properties (pos &optional output-buffer buffer)
 112   "Describe widgets, buttons, overlays, and text properties at POS.
 113 POS is taken to be in BUFFER or in current buffer if nil.
 114 Interactively, describe them for the character after point.
 115 If optional second argument OUTPUT-BUFFER is non-nil,
 116 insert the output into that buffer, and don't initialize or clear it
 117 otherwise."
 118   (interactive "d")
 119   (let ((src-buf (current-buffer)))
 120     (if buffer (set-buffer buffer) (setq buffer (current-buffer)))
 121   (if (>= pos (point-max))
 122       (error "No character follows specified position"))
 123   (if output-buffer
 124       (describe-text-properties-1 pos output-buffer)
 125     (if (not (or (text-properties-at pos) (overlays-at pos)))
 126         (message "This is plain text.")
 127         (with-temp-buffer
 128             (setq output-buffer (current-buffer))
 129             (insert "Text content at position " (format "%d" pos) ":\n\n")
 130           (set-buffer buffer)
 131           (describe-text-properties-1 pos output-buffer)
 132           (set-buffer src-buf)
 133           (help-setup-xref (list 'describe-text-properties pos nil buffer)
 134                            (called-interactively-p 'interactive))
 135           (with-help-window (help-buffer)
 136             (with-current-buffer standard-output
 137               (buffer-swap-text output-buffer)
 138               (goto-char (point-min)))))))))
 139
 140 (defun describe-text-properties-1 (pos output-buffer)
 141   (let* ((properties (text-properties-at pos))
 142          (overlays (overlays-in pos (1+ pos)))
 143          (wid-field (get-char-property pos 'field))
 144          (wid-button (get-char-property pos 'button))
 145          (wid-doc (get-char-property pos 'widget-doc))
 146          ;; If button.el is not loaded, we have no buttons in the text.
 147          (button (and (fboundp 'button-at) (button-at pos)))
 148          (button-type (and button (button-type button)))
 149          (button-label (and button (button-label button)))
 150          (widget (or wid-field wid-button wid-doc)))
 151     (with-current-buffer output-buffer
 152       ;; Widgets
 153       (when (widgetp widget)
 154         (newline)
 155         (insert (cond (wid-field "This is an editable text area")
 156                       (wid-button "This is an active area")
 157                       (wid-doc "This is documentation text")))
 158         (insert " of a ")
 159         (describe-text-widget widget)
 160         (insert ".\n\n"))
 161       ;; Buttons
 162       (when (and button (not (widgetp wid-button)))
 163         (newline)
 164         (insert "Here is a `" (format "%S" button-type)
 165                 "' button labeled `" button-label "'.\n\n"))
 166       ;; Overlays
 167       (when overlays
 168         (newline)
 169         (if (eq (length overlays) 1)
 170             (insert "There is an overlay here:\n")
 171           (insert "There are " (format "%d" (length overlays))
 172                          " overlays here:\n"))
 173         (dolist (overlay overlays)
 174           (insert " From " (format "%d" (overlay-start overlay))
 175                          " to " (format "%d" (overlay-end overlay)) "\n")
 176           (describe-property-list (overlay-properties overlay)))
 177         (insert "\n"))
 178       ;; Text properties
 179       (when properties
 180         (newline)
 181         (insert "There are text properties here:\n")
 182         (describe-property-list properties)))))
 183 \f
 184 (defcustom describe-char-unidata-list
 185   '(name old-name general-category decomposition)
 186   "List of Unicode-based character property names shown by `describe-char'."
 187   :group 'mule
 188   :version "23.1"
 189   :type '(choice (const :tag "All properties" t)
 190           (set
 191            (const :tag "Unicode name" name)
 192            (const :tag "Unicode old name" old-name)
 193            (const :tag "Unicode general category " general-category)
 194            (const :tag "Unicode canonical combining class"
 195                   canonical-combining-class)
 196            (const :tag "Unicode bidi class" bidi-class)
 197            (const :tag "Unicode decomposition mapping" decomposition)
 198            (const :tag "Unicode decimal digit value" decimal-digit-value)
 199            (const :tag "Unicode digit value" digit-value)
 200            (const :tag "Unicode numeric value" numeric-value)
 201            (const :tag "Unicode mirrored" mirrored)
 202            (const :tag "Unicode ISO 10646 comment" iso-10646-comment)
 203            (const :tag "Unicode simple uppercase mapping" uppercase)
 204            (const :tag "Unicode simple lowercase mapping" lowercase)
 205            (const :tag "Unicode simple titlecase mapping" titlecase))))
 206
 207 (defcustom describe-char-unicodedata-file nil
 208   "Location of Unicode data file.
 209 This is the UnicodeData.txt file from the Unicode Consortium, used for
 210 diagnostics.  If it is non-nil `describe-char' will print data
 211 looked up from it.  This facility is mostly of use to people doing
 212 multilingual development.
 213
 214 This is a fairly large file, not typically present on GNU systems.
 215 At the time of writing it is at the URL
 216 `http://www.unicode.org/Public/UNIDATA/UnicodeData.txt'."
 217   :group 'mule
 218   :version "22.1"
 219   :type '(choice (const :tag "None" nil)
 220                  file))
 221
 222 (defun describe-char-unicode-data (char)
 223   "Return a list of Unicode data for Unicode CHAR.
 224 Each element is a list of a property description and the property value.
 225 The list is null if CHAR isn't found in `describe-char-unicodedata-file'.
 226 This function is semi-obsolete.  Use `get-char-code-property'."
 227   (when describe-char-unicodedata-file
 228     (unless (file-exists-p describe-char-unicodedata-file)
 229       (error "`unicodedata-file' %s not found" describe-char-unicodedata-file))
 230     (with-current-buffer (get-buffer-create " *Unicode Data*")
 231       (when (zerop (buffer-size))
 232         ;; Don't use -literally in case of DOS line endings.
 233         (insert-file-contents describe-char-unicodedata-file))
 234       (goto-char (point-min))
 235       (let ((hex (format "%04X" char))
 236             found first last)
 237         (if (re-search-forward (concat "^" hex) nil t)
 238             (setq found t)
 239           ;; It's not listed explicitly.  Look for ranges, e.g. CJK
 240           ;; ideographs, and check whether it's in one of them.
 241           (while (and (re-search-forward "^\\([^;]+\\);[^;]+First>;" nil t)
 242                       (>= char (setq first
 243                                      (string-to-number (match-string 1) 16)))
 244                       (progn
 245                         (forward-line 1)
 246                         (looking-at "^\\([^;]+\\);[^;]+Last>;")
 247                         (> char
 248                            (setq last
 249                                  (string-to-number (match-string 1) 16))))))
 250           (if (and (>= char first)
 251                    (<= char last))
 252               (setq found t)))
 253         (if found
 254             (let ((fields (mapcar (lambda (elt)
 255                                     (if (> (length elt) 0)
 256                                         elt))
 257                                   (cdr (split-string
 258                                         (buffer-substring
 259                                          (line-beginning-position)
 260                                          (line-end-position))
 261                                         ";")))))
 262               ;; The length depends on whether the last field was empty.
 263               (unless (or (= 13 (length fields))
 264                           (= 14 (length fields)))
 265                 (error "Invalid contents in %s" describe-char-unicodedata-file))
 266               ;; The field names and values lists are slightly
 267               ;; modified from Mule-UCS unidata.el.
 268               (list
 269                (list "Name" (let ((name (nth 0 fields)))
 270                               ;; Check for <..., First>, <..., Last>
 271                               (if (string-match "\\`\\(<[^,]+\\)," name)
 272                                   (concat (match-string 1 name) ">")
 273                                 name)))
 274                (list "Category"
 275                      (let ((val (nth 1 fields)))
 276                        (or (char-code-property-description
 277                             'general-category (intern val))
 278                            val)))
 279                (list "Combining class"
 280                      (let ((val (nth 1 fields)))
 281                        (or (char-code-property-description
 282                             'canonical-combining-class (intern val))
 283                            val)))
 284                (list "Bidi category"
 285                      (let ((val (nth 1 fields)))
 286                        (or (char-code-property-description
 287                             'bidi-class (intern val))
 288                            val)))
 289                (list
 290                 "Decomposition"
 291                 (if (nth 4 fields)
 292                     (let* ((parts (split-string (nth 4 fields)))
 293                            (info (car parts)))
 294                       (if (string-match "\\`<\\(.+\\)>\\'" info)
 295                           (setq info (match-string 1 info))
 296                         (setq info nil))
 297                       (if info (setq parts (cdr parts)))
 298                       (setq parts (mapconcat
 299                                    (lambda (arg)
 300                                      (string (string-to-number arg 16)))
 301                                    parts " "))
 302                       (concat info (if info " ") parts))))
 303                (list "Decimal digit value"
 304                      (nth 5 fields))
 305                (list "Digit value"
 306                      (nth 6 fields))
 307                (list "Numeric value"
 308                      (nth 7 fields))
 309                (list "Mirrored"
 310                      (if (equal "Y" (nth 8 fields))
 311                          "yes"))
 312                (list "Old name" (nth 9 fields))
 313                (list "ISO 10646 comment" (nth 10 fields))
 314                (list "Uppercase" (and (nth 11 fields)
 315                                       (string (string-to-number
 316                                                (nth 11 fields) 16))))
 317                (list "Lowercase" (and (nth 12 fields)
 318                                       (string (string-to-number
 319                                                (nth 12 fields) 16))))
 320                (list "Titlecase" (and (nth 13 fields)
 321                                       (string (string-to-number
 322                                                (nth 13 fields) 16)))))))))))
 323
 324 ;; Not defined on builds without X, but behind display-graphic-p.
 325 (declare-function internal-char-font "fontset.c" (position &optional ch))
 326
 327 ;; Return information about how CHAR is displayed at the buffer
 328 ;; position POS.  If the selected frame is on a graphic display,
 329 ;; return a string "FONT-DRIVER:FONT-NAME (GLYPH-CODE)" where:
 330 ;;   FONT-DRIVER is the font-driver name,
 331 ;;   FONT-NAME is the font name,
 332 ;;   GLYPH-CODE is a hexadigit string representing the glyph-ID.
 333 ;; Otherwise, return a string describing the terminal codes for the
 334 ;; character.
 335 (defun describe-char-display (pos char)
 336   (if (display-graphic-p (selected-frame))
 337       (let ((char-font-info (internal-char-font pos char)))
 338         (if char-font-info
 339             (let ((type (font-get (car char-font-info) :type))
 340                   (name (font-xlfd-name (car char-font-info)))
 341                   (code (cdr char-font-info)))
 342                (if (integerp code)
 343                    (format "%s:%s (#x%02X)" type name code)
 344                  (format "%s:%s (#x%04X%04X)"
 345                          type name (car code) (cdr code))))))
 346     (let* ((charset (get-text-property pos 'charset))
 347            (coding (or (terminal-coding-system) 'us-ascii))
 348            (encoded (encode-coding-char char coding charset)))
 349       (if encoded
 350           (encoded-string-description encoded coding)))))
 351
 352 \f
 353 ;; Return a string of CH with composition for padding on both sides.
 354 ;; It is displayed without overlapping with the left/right columns.
 355 (defsubst describe-char-padded-string (ch)
 356   (if (and (display-multi-font-p)
 357            (internal-char-font nil ch))
 358       (compose-string (string ch) 0 1 (format "\t%c\t" ch))
 359     (string ch)))
 360
 361 ;; Return a nicely formatted list of categories; extended category
 362 ;; description is added to the category name as a tooltip
 363 (defsubst describe-char-categories (category-set)
 364   (let ((mnemonics (category-set-mnemonics category-set)))
 365     (unless (eq mnemonics "")
 366       (list (mapconcat
 367              (lambda (x)
 368                (let* ((c (category-docstring x))
 369                       (doc (if (string-match "\\`\\(.*?\\)\n" c)
 370                                (propertize (match-string 1 c)
 371                                            'help-echo
 372                                            (substring c (1+ (match-end 1))))
 373                              c)))
 374                  (format "%c:%s" x doc)))
 375              mnemonics ", ")))))
 376
 377 (declare-function quail-find-key "quail" (char))
 378
 379 ;;;###autoload
 380 (defun describe-char (pos &optional buffer)
 381   "Describe position POS (interactively, point) and the char after POS.
 382 POS is taken to be in BUFFER, or the current buffer if BUFFER is nil.
 383 The information is displayed in buffer `*Help*'.
 384
 385 The position information includes POS; the total size of BUFFER; the
 386 region limits, if narrowed; the column number; and the horizontal
 387 scroll amount, if the buffer is horizontally scrolled.
 388
 389 The character information includes the character code; charset and
 390 code points in it; syntax; category; how the character is encoded in
 391 BUFFER and in BUFFER's file; character composition information (if
 392 relevant); the font and font glyphs used to display the character;
 393 the character's canonical name and other properties defined by the
 394 Unicode Data Base; and widgets, buttons, overlays, and text properties
 395 relevant to POS."
 396   (interactive "d")
 397   (unless (buffer-live-p buffer) (setq buffer (current-buffer)))
 398   (let ((src-buf (current-buffer)))
 399     (set-buffer buffer)
 400     (if (>= pos (point-max))
 401         (error "No character follows specified position"))
 402     (let* ((char (char-after pos))
 403            (eight-bit-p (and (not enable-multibyte-characters) (>= char 128)))
 404            (charset (if eight-bit-p 'eight-bit
 405                       (or (get-text-property pos 'charset)
 406                           (char-charset char))))
 407            (composition (find-composition pos nil nil t))
 408            (component-chars nil)
 409            (display-table (or (window-display-table)
 410                               buffer-display-table
 411                               standard-display-table))
 412            (disp-vector (and display-table (aref display-table char)))
 413            (multibyte-p enable-multibyte-characters)
 414            (overlays (mapcar (lambda (o) (overlay-properties o))
 415                              (overlays-at pos)))
 416            (char-description (if (not multibyte-p)
 417                                  (single-key-description char)
 418                                (if (< char 128)
 419                                    (single-key-description char)
 420                                  (string-to-multibyte
 421                                   (char-to-string char)))))
 422            (text-props-desc
 423             (let ((tmp-buf (generate-new-buffer " *text-props*")))
 424               (unwind-protect
 425                   (progn
 426                     (describe-text-properties pos tmp-buf)
 427                     (with-current-buffer tmp-buf (buffer-string)))
 428                 (kill-buffer tmp-buf))))
 429            item-list max-width code)
 430
 431       (if multibyte-p
 432           (or (setq code (encode-char char charset))
 433               (setq charset (char-charset char)
 434                     code (encode-char char charset)))
 435         (setq code char))
 436       (cond
 437        ;; Append a PDF character to directional embeddings and
 438        ;; overrides, to prevent potential messup of the following
 439        ;; text.
 440        ((memq char '(?\x202a ?\x202b ?\x202d ?\x202e))
 441         (setq char-description
 442               (concat char-description
 443                       (propertize (string ?\x202c) 'invisible t))))
 444        ;; Append a LRM character to any strong character to avoid
 445        ;; messing up the numerical codepoint.
 446        ((memq (get-char-code-property char 'bidi-class) '(R AL))
 447         (setq char-description
 448               (concat char-description
 449                       (propertize (string ?\x200e) 'invisible t)))))
 450       (when composition
 451         ;; When the composition is trivial (i.e. composed only with the
 452         ;; current character itself without any alternate characters),
 453         ;; we don't show the composition information.  Otherwise, store
 454         ;; two descriptive strings in the first two elements of
 455         ;; COMPOSITION.
 456         (or (catch 'tag
 457               (let ((from (car composition))
 458                     (to (nth 1 composition))
 459                     (components (nth 2 composition))
 460                     ch)
 461                 (if (and (vectorp components) (vectorp (aref components 0)))
 462                     (let ((idx (- pos from))
 463                           (nglyphs (lgstring-glyph-len components))
 464                           (i 0) j glyph glyph-from)
 465                       ;; COMPONENTS is a gstring.  Find a grapheme
 466                       ;; cluster containing the current character.
 467                       (while (and (< i nglyphs)
 468                                   (setq glyph (lgstring-glyph components i))
 469                                   (< (lglyph-to glyph) idx))
 470                         (setq i (1+ i)))
 471                       (if (or (not glyph) (= i nglyphs))
 472                           ;; The composition is broken.
 473                           (throw 'tag nil))
 474                       (setq glyph-from (lglyph-from glyph)
 475                             to (+ from (lglyph-to glyph) 1)
 476                             from (+ from glyph-from)
 477                             j i)
 478                       (while (and (< j nglyphs)
 479                                   (setq glyph (lgstring-glyph components j))
 480                                   (= (lglyph-from glyph) glyph-from))
 481                         (setq j (1+ j)))
 482                       (if (and (= to (1+ from))
 483                                (= i (1- j))
 484                                (setq glyph (lgstring-glyph components i))
 485                                (= char (lglyph-char glyph)))
 486                           ;; The composition is trivial.
 487                           (throw 'tag nil))
 488                       (nconc composition (list i (1- j))))
 489                   (dotimes (i (length components))
 490                     (if (integerp (setq ch (aref components i)))
 491                         (push (cons ch (describe-char-display pos ch))
 492                               component-chars)))
 493                   (setq component-chars (nreverse component-chars)))
 494                 (if (< from pos)
 495                     (if (< (1+ pos) to)
 496                         (setcar composition
 497                                 (concat
 498                                  " with the surrounding characters \""
 499                                  (mapconcat 'describe-char-padded-string
 500                                             (buffer-substring from pos) "")
 501                                  "\" and \""
 502                                  (mapconcat 'describe-char-padded-string
 503                                             (buffer-substring (1+ pos) to) "")
 504                                  "\""))
 505                       (setcar composition
 506                               (concat
 507                                " with the preceding character(s) \""
 508                                (mapconcat 'describe-char-padded-string
 509                                           (buffer-substring from pos) "")
 510                                "\"")))
 511                   (if (< (1+ pos) to)
 512                       (setcar composition
 513                               (concat
 514                                " with the following character(s) \""
 515                                (mapconcat 'describe-char-padded-string
 516                                           (buffer-substring (1+ pos) to) "")
 517                                "\""))
 518                     (setcar composition nil)))
 519                 (setcar (cdr composition)
 520                         (format "composed to form \"%s\" (see below)"
 521                                 (buffer-substring from to)))))
 522             (setq composition nil)))
 523
 524       (setq item-list
 525             `(("position"
 526                ,(let* ((beg      (point-min))
 527                        (end      (point-max))
 528                        (total    (buffer-size))
 529                        (percent  (if (> total 50000) ; Avoid overflow multiplying by 100
 530                                      (/ (+ (/ total 200) (1- pos))  (max (/ total 100) 1))
 531                                    (/ (+ (/ total 2) (* 100 (1- pos)))  (max total 1))))
 532                        (hscroll  (if (= (window-hscroll) 0)
 533                                      ""
 534                                    (format ", Hscroll: %d" (window-hscroll))))
 535                        (col      (current-column)))
 536                   (if (or (/= beg 1)  (/= end (1+ total)))
 537                       (format "%d of %d (%d%%), restriction: <%d-%d>, column: %d%s"
 538                               pos total percent beg end col hscroll)
 539                     (if (= pos end)
 540                         (format "%d of %d (EOB), column: %d%s" pos total col hscroll)
 541                       (format "%d of %d (%d%%), column: %d%s"
 542                               pos total percent col hscroll)))))
 543               ("character"
 544                ,(format "%s (displayed as %s) (codepoint %d, #o%o, #x%x)"
 545                         char-description
 546                         (apply 'propertize char-description
 547                                (text-properties-at pos))
 548                         char char char))
 549               ("preferred charset"
 550                ,`(insert-text-button
 551                   ,(symbol-name charset)
 552                   'type 'help-character-set 'help-args '(,charset))
 553                ,(format "(%s)" (charset-description charset)))
 554               ("code point in charset"
 555                ,(let ((str (if (integerp code)
 556                                (format (if (< code 256) "0x%02X" "0x%04X")
 557                                        code)
 558                              (format "0x%04X%04X" (car code) (cdr code)))))
 559                   (if (<= (charset-dimension charset) 2)
 560                       `(insert-text-button
 561                         ,str
 562                         'action (lambda (&rest ignore)
 563                                   (list-charset-chars ',charset)
 564                                   (with-selected-window
 565                                       (get-buffer-window "*Character List*" 0)
 566                                     (goto-char (point-min))
 567                                     (forward-line 2) ;Skip the header.
 568                                     (let ((case-fold-search nil))
 569                                       (if (search-forward
 570                                            ,(char-to-string char) nil t)
 571                                           (goto-char (match-beginning 0))))))
 572                         'follow-link t
 573                         'help-echo
 574                         "mouse-2, RET: show this character in its character set")
 575                     str)))
 576               ,@(let ((script (aref char-script-table char)))
 577                   (if script
 578                       (list (list "script" (symbol-name script)))))
 579               ("syntax"
 580                ,(let ((syntax (syntax-after pos)))
 581                   (with-temp-buffer
 582                     (internal-describe-syntax-value syntax)
 583                     (buffer-string))))
 584               ("category"
 585                ,@(if (not eight-bit-p)
 586                      (let ((category-set (char-category-set char)))
 587                        (if category-set
 588                            (describe-char-categories category-set)
 589                          '("-- none --")))))
 590               ("to input"
 591                ,@(if (not eight-bit-p)
 592                      (let ((key-list (and (eq input-method-function
 593                                               'quail-input-method)
 594                                           (quail-find-key char))))
 595                        (if (consp key-list)
 596                            (list "type"
 597                                  (concat "\""
 598                                          (mapconcat 'identity
 599                                                     key-list "\" or \"")
 600                                          "\"")
 601                                  "with"
 602                                  `(insert-text-button
 603                                    ,current-input-method
 604                                    'type 'help-input-method
 605                                    'help-args '(,current-input-method))
 606                                  "input method")
 607                          (list
 608                           "type \"C-x 8 RET HEX-CODEPOINT\" or \"C-x 8 RET NAME\"")))))
 609               ("buffer code"
 610                ,(if multibyte-p
 611                     (encoded-string-description
 612                      (string-as-unibyte (char-to-string char)) nil)
 613                   (format "#x%02X" char)))
 614               ("file code"
 615                ,@(if multibyte-p
 616                      (let* ((coding buffer-file-coding-system)
 617                             (encoded (encode-coding-char char coding charset)))
 618                        (if encoded
 619                            (list (encoded-string-description encoded coding)
 620                                  (format "(encoded by coding system %S)"
 621                                          coding))
 622                          (list "not encodable by coding system"
 623                                (symbol-name coding))))
 624                    (list (format "#x%02X" char))))
 625               ("display"
 626                ,(cond
 627                  (disp-vector
 628                   (setq disp-vector (copy-sequence disp-vector))
 629                   (dotimes (i (length disp-vector))
 630                     (aset disp-vector i
 631                           (cons (aref disp-vector i)
 632                                 (describe-char-display
 633                                  pos (glyph-char (aref disp-vector i))))))
 634                   (format "by display table entry [%s] (see below)"
 635                           (mapconcat
 636                            (lambda (x)
 637                              (format "?%c" (glyph-char (car x))))
 638                            disp-vector " ")))
 639                  (composition
 640                   (cadr composition))
 641                  (t
 642                   (let ((display (describe-char-display pos char)))
 643                     (if (display-graphic-p (selected-frame))
 644                         (if display
 645                             (concat "by this font (glyph code)\n    " display)
 646                           "no font available")
 647                       (if display
 648                           (format "terminal code %s" display)
 649                         "not encodable for terminal"))))))
 650               ,@(let ((face
 651                        (if (not (or disp-vector composition))
 652                            (cond
 653                             ((and show-trailing-whitespace
 654                                   (save-excursion (goto-char pos)
 655                                                   (looking-at-p "[ \t]+$")))
 656                              'trailing-whitespace)
 657                             ((and nobreak-char-display char (eq char '#xa0))
 658                              'nobreak-space)
 659                             ((and nobreak-char-display char
 660                                   (memq char '(#xad #x2010 #x2011)))
 661                              'escape-glyph)
 662                             ((and (< char 32) (not (memq char '(9 10))))
 663                              'escape-glyph)))))
 664                   (if face (list (list "hardcoded face"
 665                                        `(insert-text-button ;FIXME: Wrap in lambda!
 666                                          ,(symbol-name face)
 667                                          'type 'help-face
 668                                          'help-args '(,face))))))
 669               ,@(if (not eight-bit-p)
 670                     (let ((unicodedata (describe-char-unicode-data char)))
 671                       (if unicodedata
 672                           (cons (list "Unicode data" "") unicodedata))))))
 673       (setq max-width (apply 'max (mapcar (lambda (x)
 674                                             (if (cadr x) (length (car x)) 0))
 675                                           item-list)))
 676       (set-buffer src-buf)
 677       (help-setup-xref (list 'describe-char pos buffer)
 678                        (called-interactively-p 'interactive))
 679       (with-help-window (help-buffer)
 680         (with-current-buffer standard-output
 681           (set-buffer-multibyte multibyte-p)
 682           (let ((formatter (format "%%%ds:" max-width)))
 683             (dolist (elt item-list)
 684               (when (cadr elt)
 685                 (insert (format formatter (car elt)))
 686                 (dolist (clm (cdr elt))
 687                   (cond ((eq (car-safe clm) 'insert-text-button)
 688                          (insert " ")
 689                          (eval clm))
 690                         ((not (zerop (length clm)))
 691                          (insert " " clm))))
 692                 (insert "\n"))))
 693
 694           (when overlays
 695             (save-excursion
 696               (goto-char (point-min))
 697               (re-search-forward "(displayed as ")
 698               (let ((end (+ (point) (length char-description))))
 699                 (mapc (lambda (props)
 700                         (let ((o (make-overlay (point) end)))
 701                           (while props
 702                             (overlay-put o (car props) (nth 1 props))
 703                             (setq props (cddr props)))))
 704                       overlays))))
 705
 706           (when disp-vector
 707             (insert
 708              "\nThe display table entry is displayed by ")
 709             (if (display-graphic-p (selected-frame))
 710                 (progn
 711                   (insert "these fonts (glyph codes):\n")
 712                   (dotimes (i (length disp-vector))
 713                     (insert (glyph-char (car (aref disp-vector i))) ?:
 714                             (propertize " " 'display '(space :align-to 5))
 715                             (or (cdr (aref disp-vector i)) "-- no font --")
 716                             "\n")
 717                     (let ((face (glyph-face (car (aref disp-vector i)))))
 718                       (when face
 719                         (insert (propertize " " 'display '(space :align-to 5))
 720                                 "face: ")
 721                         (insert (concat "`" (symbol-name face) "'"))
 722                         (insert "\n")))))
 723               (insert "these terminal codes:\n")
 724               (dotimes (i (length disp-vector))
 725                 (insert (car (aref disp-vector i))
 726                         (propertize " " 'display '(space :align-to 5))
 727                         (or (cdr (aref disp-vector i)) "-- not encodable --")
 728                         "\n"))))
 729
 730           (when composition
 731             (insert "\nComposed")
 732             (if (car composition)
 733                 (insert (car composition)))
 734             (if (and (vectorp (nth 2 composition))
 735                      (vectorp (aref (nth 2 composition) 0)))
 736                 (let* ((gstring (nth 2 composition))
 737                        (font (lgstring-font gstring))
 738                        (from (nth 3 composition))
 739                        (to (nth 4 composition))
 740                        glyph)
 741                   (if (fontp font)
 742                       (progn
 743                         (insert " using this font:\n  "
 744                                 (symbol-name (font-get font :type))
 745                                 ?:
 746                                 (aref (query-font font) 0)
 747                                 "\nby these glyphs:\n")
 748                         (while (and (<= from to)
 749                                     (setq glyph (lgstring-glyph gstring from)))
 750                           (insert (format "  %S\n" glyph))
 751                           (setq from (1+ from))))
 752                     (insert " by these characters:\n")
 753                     (while (and (<= from to)
 754                                 (setq glyph (lgstring-glyph gstring from)))
 755                       (insert (format " %c (#x%x)\n"
 756                                       (lglyph-char glyph) (lglyph-char glyph)))
 757                       (setq from (1+ from)))))
 758               (insert " by the rule:\n\t(")
 759               (let ((first t))
 760                 (mapc (lambda (x)
 761                         (if first (setq first nil)
 762                           (insert " "))
 763                         (if (consp x) (insert (format "%S" x))
 764                           (if (= x ?\t) (insert (single-key-description x))
 765                             (insert ??)
 766                             (insert (describe-char-padded-string x)))))
 767                       (nth 2 composition)))
 768               (insert  ")\nThe component character(s) are displayed by ")
 769               (if (display-graphic-p (selected-frame))
 770                   (progn
 771                     (insert "these fonts (glyph codes):")
 772                     (dolist (elt component-chars)
 773                       (if (/= (car elt) ?\t)
 774                           (insert "\n "
 775                                   (describe-char-padded-string (car elt))
 776                                   ?:
 777                                   (propertize " "
 778                                               'display '(space :align-to 5))
 779                                   (or (cdr elt) "-- no font --")))))
 780                 (insert "these terminal codes:")
 781                 (dolist (elt component-chars)
 782                   (insert "\n  " (car elt) ":"
 783                           (propertize " " 'display '(space :align-to 4))
 784                           (or (cdr elt) "-- not encodable --"))))
 785               (insert "\nSee the variable `reference-point-alist' for "
 786                       "the meaning of the rule.\n")))
 787
 788           (unless eight-bit-p
 789             (insert (if (not describe-char-unidata-list)
 790                         "\nCharacter code properties are not shown: "
 791                       "\nCharacter code properties: "))
 792             (insert-text-button
 793              "customize what to show"
 794              'action (lambda (&rest _ignore)
 795                        (customize-variable
 796                         'describe-char-unidata-list))
 797              'follow-link t)
 798             (insert "\n")
 799             (dolist (elt (if (eq describe-char-unidata-list t)
 800                              (nreverse (mapcar 'car char-code-property-alist))
 801                            describe-char-unidata-list))
 802               (let ((val (get-char-code-property char elt))
 803                     description)
 804                 (when val
 805                   (setq description (char-code-property-description elt val))
 806                   (insert (if description
 807                               (format "  %s: %s (%s)\n" elt val description)
 808                             (format "  %s: %s\n" elt val)))))))
 809
 810           (if text-props-desc (insert text-props-desc))
 811           (setq buffer-read-only t))))))
 812
 813 (define-obsolete-function-alias 'describe-char-after 'describe-char "22.1")
 814
 815 (provide 'descr-text)
 816
 817 ;;; descr-text.el ends here