code.delx.au - gnu-emacs/blob - lisp/textmodes/enriched.el

   1 ;;; enriched.el --- read and save files in text/enriched format
   2
   3 ;; Copyright (C) 1994-1996, 2001-2011  Free Software Foundation, Inc.
   4
   5 ;; Author: Boris Goldowsky <boris@gnu.org>
   6 ;; Keywords: wp, 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 3 of the License, or
  13 ;; (at your option) 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.  If not, see <http://www.gnu.org/licenses/>.
  22
  23 ;;; Commentary:
  24
  25 ;; This file implements reading, editing, and saving files with
  26 ;; text-properties such as faces, levels of indentation, and true line
  27 ;; breaks distinguished from newlines just used to fit text into the window.
  28
  29 ;; The file format used is the MIME text/enriched format, which is a
  30 ;; standard format defined in internet RFC 1563.  All standard annotations
  31 ;; are supported except for <smaller> and <bigger>, which are currently not
  32 ;; possible to display.
  33
  34 ;; A separate file, enriched.doc, contains further documentation and other
  35 ;; important information about this code.  It also serves as an example
  36 ;; file in text/enriched format.  It should be in the etc directory of your
  37 ;; emacs distribution.
  38
  39 ;;; Code:
  40
  41 (provide 'enriched)
  42
  43 ;;;
  44 ;;; Variables controlling the display
  45 ;;;
  46
  47 (defgroup enriched nil
  48   "Read and save files in text/enriched format."
  49   :group 'wp)
  50
  51 (defcustom enriched-verbose t
  52   "If non-nil, give status messages when reading and writing files."
  53   :type 'boolean
  54   :group 'enriched)
  55
  56 ;;;
  57 ;;; Set up faces & display table
  58 ;;;
  59
  60 ;; Emacs doesn't have a "fixed" face by default, since all faces currently
  61 ;; have to be fixed-width.  So we just pick one that looks different from the
  62 ;; default.
  63 (defface fixed
  64   '((t (:weight bold)))
  65   "Face used for text that must be shown in fixed width.
  66 Currently, Emacs can only display fixed-width fonts, but this may change.
  67 This face is used for text specifically marked as fixed-width, for example
  68 in text/enriched files."
  69   :group 'enriched)
  70
  71 (defface excerpt
  72   '((t (:slant italic)))
  73   "Face used for text that is an excerpt from another document.
  74 This is used in Enriched mode for text explicitly marked as an excerpt."
  75   :group 'enriched)
  76
  77 (defconst enriched-display-table (or (copy-sequence standard-display-table)
  78                                      (make-display-table)))
  79 (aset enriched-display-table ?\f (make-vector (1- (frame-width)) ?-))
  80
  81 (defconst enriched-par-props '(left-margin right-margin justification)
  82   "Text-properties that usually apply to whole paragraphs.
  83 These are set front-sticky everywhere except at hard newlines.")
  84
  85 ;;;
  86 ;;; Variables controlling the file format
  87 ;;;   (bidirectional)
  88
  89 (defconst enriched-initial-annotation
  90   (lambda ()
  91     (format "Content-Type: text/enriched\nText-Width: %d\n\n"
  92             fill-column))
  93   "What to insert at the start of a text/enriched file.
  94 If this is a string, it is inserted.  If it is a list, it should be a lambda
  95 expression, which is evaluated to get the string to insert.")
  96
  97 (defconst enriched-annotation-format "<%s%s>"
  98   "General format of enriched-text annotations.")
  99
 100 (defconst enriched-annotation-regexp "<\\(/\\)?\\([-A-Za-z0-9]+\\)>"
 101   "Regular expression matching enriched-text annotations.")
 102
 103 (defvar enriched-translations
 104   '((face          (bold-italic "bold" "italic")
 105                    (bold        "bold")
 106                    (italic      "italic")
 107                    (underline   "underline")
 108                    (fixed       "fixed")
 109                    (excerpt     "excerpt")
 110                    (default     )
 111                    (nil         enriched-encode-other-face))
 112     (left-margin   (4           "indent"))
 113     (right-margin  (4           "indentright"))
 114     (justification (none        "nofill")
 115                    (right       "flushright")
 116                    (left        "flushleft")
 117                    (full        "flushboth")
 118                    (center      "center"))
 119     (PARAMETER     (t           "param")) ; Argument of preceding annotation
 120     ;; The following are not part of the standard:
 121     (FUNCTION      (enriched-decode-foreground "x-color")
 122                    (enriched-decode-background "x-bg-color")
 123                    (enriched-decode-display-prop "x-display"))
 124     (read-only     (t           "x-read-only"))
 125     (display       (nil         enriched-handle-display-prop))
 126     (unknown       (nil         format-annotate-value))
 127 ;   (font-size     (2           "bigger")       ; unimplemented
 128 ;                  (-2          "smaller"))
 129 )
 130   "List of definitions of text/enriched annotations.
 131 See `format-annotate-region' and `format-deannotate-region' for the definition
 132 of this structure.")
 133
 134 (defconst enriched-ignore
 135   '(front-sticky rear-nonsticky hard)
 136   "Properties that are OK to ignore when saving text/enriched files.
 137 Any property that is neither on this list nor dealt with by
 138 `enriched-translations' will generate a warning.")
 139
 140 ;;; Internal variables
 141
 142 (defcustom enriched-mode-hook nil
 143   "Hook run after entering/leaving Enriched mode.
 144 If you set variables in this hook, you should arrange for them to be restored
 145 to their old values if you leave Enriched mode.  One way to do this is to add
 146 them and their old values to `enriched-old-bindings'."
 147   :type 'hook
 148   :group 'enriched)
 149
 150 (defvar enriched-old-bindings nil
 151   "Store old variable values that we change when entering mode.
 152 The value is a list of \(VAR VALUE VAR VALUE...).")
 153 (make-variable-buffer-local 'enriched-old-bindings)
 154
 155 ;; The next variable is buffer local if and only if Enriched mode is
 156 ;; enabled.  The buffer local value records whether
 157 ;; `default-text-properties' should remain buffer local when disabling
 158 ;; Enriched mode.  For technical reasons, the default value should be t.
 159 (defvar enriched-default-text-properties-local-flag t)
 160
 161 ;; Technical internal variable.  Bound to t if `enriched-mode' is
 162 ;; being rerun by a major mode to allow it to restore buffer-local
 163 ;; variables and to correctly update `enriched-old-bindings'.
 164 (defvar enriched-rerun-flag nil)
 165
 166 ;;;
 167 ;;; Define the mode
 168 ;;;
 169
 170 (put 'enriched-mode 'permanent-local t)
 171 ;;;###autoload
 172 (define-minor-mode enriched-mode
 173   "Minor mode for editing text/enriched files.
 174 These are files with embedded formatting information in the MIME standard
 175 text/enriched format.
 176 Turning the mode on or off runs `enriched-mode-hook'.
 177
 178 More information about Enriched mode is available in the file
 179 etc/enriched.doc in the Emacs distribution directory.
 180
 181 Commands:
 182
 183 \\{enriched-mode-map}"
 184   :group 'enriched :lighter " Enriched"
 185   (cond ((null enriched-mode)
 186          ;; Turn mode off
 187          (setq buffer-file-format (delq 'text/enriched buffer-file-format))
 188          ;; restore old variable values
 189          (while enriched-old-bindings
 190            (set (pop enriched-old-bindings) (pop enriched-old-bindings)))
 191          (unless enriched-default-text-properties-local-flag
 192            (kill-local-variable 'default-text-properties))
 193          (kill-local-variable 'enriched-default-text-properties-local-flag)
 194          (unless use-hard-newlines (use-hard-newlines 0)))
 195
 196         ((and (memq 'text/enriched buffer-file-format)
 197               (not enriched-rerun-flag))
 198          ;; Mode already on; do nothing.
 199          nil)
 200
 201         (t                              ; Turn mode on
 202          (add-to-list 'buffer-file-format 'text/enriched)
 203          ;; Save old variable values before we change them.
 204          ;; These will be restored if we exit Enriched mode.
 205          (setq enriched-old-bindings
 206                (list 'buffer-display-table buffer-display-table
 207                      'default-text-properties default-text-properties
 208                      'use-hard-newlines use-hard-newlines))
 209          (make-local-variable 'enriched-default-text-properties-local-flag)
 210          (setq enriched-default-text-properties-local-flag
 211                (local-variable-p 'default-text-properties))
 212          (make-local-variable 'default-text-properties)
 213          (setq buffer-display-table  enriched-display-table)
 214          (use-hard-newlines 1 (if enriched-rerun-flag 'never nil))
 215          (let ((sticky (plist-get default-text-properties 'front-sticky))
 216                (p enriched-par-props))
 217            (dolist (x p)
 218              (add-to-list 'sticky x))
 219            (if sticky
 220                (setq default-text-properties
 221                      (plist-put default-text-properties
 222                                 'front-sticky sticky)))))))
 223
 224 (defun enriched-before-change-major-mode ()
 225   (when enriched-mode
 226     (while enriched-old-bindings
 227       (set (pop enriched-old-bindings) (pop enriched-old-bindings)))))
 228
 229 (add-hook 'change-major-mode-hook 'enriched-before-change-major-mode)
 230
 231 (defun enriched-after-change-major-mode ()
 232   (when enriched-mode
 233     (let ((enriched-rerun-flag t))
 234       (enriched-mode 1))))
 235
 236 (add-hook 'after-change-major-mode-hook 'enriched-after-change-major-mode)
 237
 238 ;;;
 239 ;;; Keybindings
 240 ;;;
 241
 242 (defvar enriched-mode-map nil
 243   "Keymap for Enriched mode.")
 244
 245 (if (null enriched-mode-map)
 246     (fset 'enriched-mode-map (setq enriched-mode-map (make-sparse-keymap))))
 247
 248 (if (not (assq 'enriched-mode minor-mode-map-alist))
 249     (setq minor-mode-map-alist
 250           (cons (cons 'enriched-mode enriched-mode-map)
 251                 minor-mode-map-alist)))
 252
 253 (define-key enriched-mode-map [remap move-beginning-of-line] 'beginning-of-line-text)
 254 (define-key enriched-mode-map "\C-m" 'reindent-then-newline-and-indent)
 255 (define-key enriched-mode-map
 256   [remap newline-and-indent] 'reindent-then-newline-and-indent)
 257 (define-key enriched-mode-map "\M-j" 'facemenu-justification-menu)
 258 (define-key enriched-mode-map "\M-S" 'set-justification-center)
 259 (define-key enriched-mode-map "\C-x\t" 'increase-left-margin)
 260 (define-key enriched-mode-map "\C-c[" 'set-left-margin)
 261 (define-key enriched-mode-map "\C-c]" 'set-right-margin)
 262
 263 ;;;
 264 ;;; Some functions dealing with text-properties, especially indentation
 265 ;;;
 266
 267 (defun enriched-map-property-regions (prop func &optional from to)
 268   "Apply a function to regions of the buffer based on a text property.
 269 For each contiguous region of the buffer for which the value of PROPERTY is
 270 eq, the FUNCTION will be called.  Optional arguments FROM and TO specify the
 271 region over which to scan.
 272
 273 The specified function receives three arguments: the VALUE of the property in
 274 the region, and the START and END of each region."
 275   (save-excursion
 276     (save-restriction
 277       (if to (narrow-to-region (point-min) to))
 278       (goto-char (or from (point-min)))
 279       (let ((begin (point))
 280             end
 281             (marker (make-marker))
 282             (val (get-text-property (point) prop)))
 283         (while (setq end (text-property-not-all begin (point-max) prop val))
 284           (move-marker marker end)
 285           (funcall func val begin (marker-position marker))
 286           (setq begin (marker-position marker)
 287                 val (get-text-property marker prop)))
 288         (if (< begin (point-max))
 289             (funcall func val begin (point-max)))))))
 290
 291 (put 'enriched-map-property-regions 'lisp-indent-hook 1)
 292
 293 (defun enriched-insert-indentation (&optional from to)
 294   "Indent and justify each line in the region."
 295   (save-excursion
 296     (save-restriction
 297       (if to (narrow-to-region (point-min) to))
 298       (goto-char (or from (point-min)))
 299       (if (not (bolp)) (forward-line 1))
 300       (while (not (eobp))
 301         (if (eolp)
 302             nil ; skip blank lines
 303           (indent-to (current-left-margin))
 304           (justify-current-line t nil t))
 305         (forward-line 1)))))
 306
 307 ;;;
 308 ;;; Encoding Files
 309 ;;;
 310
 311 ;;;###autoload
 312 (defun enriched-encode (from to orig-buf)
 313   (if enriched-verbose (message "Enriched: encoding document..."))
 314   (let ((inhibit-read-only t))
 315     (save-restriction
 316       (narrow-to-region from to)
 317       (delete-to-left-margin)
 318       (unjustify-region)
 319       (goto-char from)
 320       (format-replace-strings '(("<" . "<<")))
 321       (format-insert-annotations
 322        (format-annotate-region from (point-max) enriched-translations
 323                                'enriched-make-annotation enriched-ignore))
 324       (goto-char from)
 325       (insert (if (stringp enriched-initial-annotation)
 326                   enriched-initial-annotation
 327                 (save-excursion
 328                   ;; Eval this in the buffer we are annotating.  This
 329                   ;; fixes a bug which was saving incorrect File-Width
 330                   ;; information, since we were looking at local
 331                   ;; variables in the wrong buffer.
 332                   (if orig-buf (set-buffer orig-buf))
 333                   (funcall enriched-initial-annotation))))
 334       (enriched-map-property-regions 'hard
 335         (lambda (v b e)
 336           (if (and v (= ?\n (char-after b)))
 337               (progn (goto-char b) (insert "\n"))))
 338         (point) nil)
 339       (if enriched-verbose (message nil))
 340       ;; Return new end.
 341       (point-max))))
 342
 343 (defun enriched-make-annotation (internal-ann positive)
 344   "Format an annotation INTERNAL-ANN.
 345 INTERNAL-ANN may be a string, for a flag, or a list of the form (PARAM VALUE).
 346 If POSITIVE is non-nil, this is the opening annotation;
 347 if nil, the matching close."
 348   (cond ((stringp internal-ann)
 349          (format enriched-annotation-format (if positive "" "/") internal-ann))
 350         ;; Otherwise it is an annotation with parameters, represented as a list
 351         (positive
 352          (let ((item (car internal-ann))
 353                (params (cdr internal-ann)))
 354            (concat (format enriched-annotation-format "" item)
 355                    (mapconcat (lambda (i) (concat "<param>" i "</param>"))
 356                               params ""))))
 357         (t (format enriched-annotation-format "/" (car internal-ann)))))
 358
 359 (defun enriched-encode-other-face (old new)
 360   "Generate annotations for random face change.
 361 One annotation each for foreground color, background color, italic, etc."
 362   (cons (and old (enriched-face-ans old))
 363         (and new (enriched-face-ans new))))
 364
 365 (defun enriched-face-ans (face)
 366   "Return annotations specifying FACE.
 367 FACE may be a list of faces instead of a single face;
 368 it can also be anything allowed as an element of a list
 369 which can be the value of the `face' text property."
 370   (cond ((and (consp face) (eq (car face) 'foreground-color))
 371          (list (list "x-color" (cdr face))))
 372         ((and (consp face) (eq (car face) 'background-color))
 373          (list (list "x-bg-color" (cdr face))))
 374         ((and (listp face) (eq (car face) :foreground))
 375          (list (list "x-color" (cadr face))))
 376         ((and (listp face) (eq (car face) :background))
 377          (list (list "x-bg-color" (cadr face))))
 378         ((listp face)
 379          (apply 'append (mapcar 'enriched-face-ans face)))
 380         ((let* ((fg (face-attribute face :foreground))
 381                 (bg (face-attribute face :background))
 382                 (props (face-font face t))
 383                 (ans (cdr (format-annotate-single-property-change
 384                            'face nil props enriched-translations))))
 385            (unless (eq fg 'unspecified)
 386              (setq ans (cons (list "x-color" fg) ans)))
 387            (unless (eq bg 'unspecified)
 388              (setq ans (cons (list "x-bg-color" bg) ans)))
 389            ans))))
 390
 391 ;;;
 392 ;;; Decoding files
 393 ;;;
 394
 395 ;;;###autoload
 396 (defun enriched-decode (from to)
 397   (if enriched-verbose (message "Enriched: decoding document..."))
 398   (use-hard-newlines 1 'never)
 399   (save-excursion
 400     (save-restriction
 401       (narrow-to-region from to)
 402       (goto-char from)
 403
 404       ;; Deal with header
 405       (let ((file-width (enriched-get-file-width)))
 406         (enriched-remove-header)
 407
 408         ;; Deal with newlines
 409         (while (search-forward-regexp "\n\n+" nil t)
 410           (if (current-justification)
 411               (delete-char -1))
 412           (set-hard-newline-properties (match-beginning 0) (point)))
 413
 414         ;; Translate annotations
 415         (format-deannotate-region from (point-max) enriched-translations
 416                                   'enriched-next-annotation)
 417
 418         ;; Indent or fill the buffer
 419         (cond (file-width               ; File was filled to this width
 420                (setq fill-column file-width)
 421                (if enriched-verbose (message "Indenting..."))
 422                (enriched-insert-indentation))
 423               (t                        ; File was not filled.
 424                (if enriched-verbose (message "Filling paragraphs..."))
 425                (fill-region (point-min) (point-max))))
 426         (if enriched-verbose (message nil)))
 427       (point-max))))
 428
 429 (defun enriched-next-annotation ()
 430   "Find and return next text/enriched annotation.
 431 Any \"<<\" strings encountered are converted to \"<\".
 432 Return value is \(begin end name positive-p), or nil if none was found."
 433   (while (and (search-forward "<" nil 1)
 434               (progn (goto-char (match-beginning 0))
 435                      (not (looking-at enriched-annotation-regexp))))
 436     (forward-char 1)
 437     (if (= ?< (char-after (point)))
 438         (delete-char 1)
 439       ;; A single < that does not start an annotation is an error,
 440       ;; which we note and then ignore.
 441       (message "Warning: malformed annotation in file at %s"
 442                (1- (point)))))
 443   (if (not (eobp))
 444       (let* ((beg (match-beginning 0))
 445              (end (match-end 0))
 446              (name (downcase (buffer-substring
 447                               (match-beginning 2) (match-end 2))))
 448              (pos (not (match-beginning 1))))
 449         (list beg end name pos))))
 450
 451 (defun enriched-get-file-width ()
 452   "Look for file width information on this line."
 453   (save-excursion
 454     (if (search-forward "Text-Width: " (+ (point) 1000) t)
 455         (read (current-buffer)))))
 456
 457 (defun enriched-remove-header ()
 458   "Remove file-format header at point."
 459   (while (looking-at "^[-A-Za-z]+: .*\n")
 460     (delete-region (point) (match-end 0)))
 461   (if (looking-at "^\n")
 462       (delete-char 1)))
 463
 464 (defun enriched-decode-foreground (from to &optional color)
 465   (if color
 466       (list from to 'face (list ':foreground color))
 467     (message "Warning: no color specified for <x-color>")
 468     nil))
 469
 470 (defun enriched-decode-background (from to &optional color)
 471   (if color
 472       (list from to 'face (list ':background color))
 473     (message "Warning: no color specified for <x-bg-color>")
 474     nil))
 475 \f
 476 ;;; Handling the `display' property.
 477
 478
 479 (defun enriched-handle-display-prop (old new)
 480   "Return a list of annotations for a change in the `display' property.
 481 OLD is the old value of the property, NEW is the new value.  Value
 482 is a list `(CLOSE OPEN)', where CLOSE is a list of annotations to
 483 close and OPEN a list of annotations to open.  Each of these lists
 484 has the form `(ANNOTATION PARAM ...)'."
 485   (let ((annotation "x-display")
 486         (param (prin1-to-string (or old new))))
 487     (if (null old)
 488         (cons nil (list (list annotation param)))
 489       (cons (list (list annotation param)) nil))))
 490
 491 (defun enriched-decode-display-prop (start end &optional param)
 492   "Decode a `display' property for text between START and END.
 493 PARAM is a `<param>' found for the property.
 494 Value is a list `(START END SYMBOL VALUE)' with START and END denoting
 495 the range of text to assign text property SYMBOL with value VALUE."
 496   (let ((prop (when (stringp param)
 497                 (condition-case ()
 498                     (car (read-from-string param))
 499                   (error nil)))))
 500     (unless prop
 501       (message "Warning: invalid <x-display> parameter %s" param))
 502     (list start end 'display prop)))
 503
 504 ;;; enriched.el ends here