Source

emacs / lisp / xml.el

Full commit
  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
;;; xml.el --- XML parser

;; Copyright (C) 2000, 2001, 2002, 2003, 2004,
;;   2005, 2006 Free Software Foundation, Inc.

;; Author: Emmanuel Briot  <briot@gnat.com>
;; Maintainer: Mark A. Hershberger <mah@everybody.org>
;; Keywords: xml, data

;; This file is part of GNU Emacs.

;; GNU Emacs is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation; either version 2, or (at your option)
;; any later version.

;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs; see the file COPYING.  If not, write to the
;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
;; Boston, MA 02110-1301, USA.

;;; Commentary:

;; This file contains a somewhat incomplete non-validating XML parser.  It
;; parses a file, and returns a list that can be used internally by
;; any other Lisp libraries.

;;; FILE FORMAT

;; The document type declaration may either be ignored or (optionally)
;; parsed, but currently the parsing will only accept element
;; declarations.  The XML file is assumed to be well-formed.  In case
;; of error, the parsing stops and the XML file is shown where the
;; parsing stopped.
;;
;; It also knows how to ignore comments and processing instructions.
;;
;; The XML file should have the following format:
;;    <node1 attr1="name1" attr2="name2" ...>value
;;       <node2 attr3="name3" attr4="name4">value2</node2>
;;       <node3 attr5="name5" attr6="name6">value3</node3>
;;    </node1>
;; Of course, the name of the nodes and attributes can be anything.  There can
;; be any number of attributes (or none), as well as any number of children
;; below the nodes.
;;
;; There can be only top level node, but with any number of children below.

;;; LIST FORMAT

;; The functions `xml-parse-file', `xml-parse-region' and
;; `xml-parse-tag' return a list with the following format:
;;
;;    xml-list   ::= (node node ...)
;;    node       ::= (qname attribute-list . child_node_list)
;;    child_node_list ::= child_node child_node ...
;;    child_node ::= node | string
;;    qname      ::= (:namespace-uri . "name") | "name"
;;    attribute_list ::= ((qname . "value") (qname . "value") ...)
;;                       | nil
;;    string     ::= "..."
;;
;; Some macros are provided to ease the parsing of this list.
;; Whitespace is preserved.  Fixme: There should be a tree-walker that
;; can remove it.

;; TODO:
;;  * xml:base, xml:space support
;;  * more complete DOCTYPE parsing
;;  * pi support

;;; Code:

;; Note that {buffer-substring,match-string}-no-properties were
;; formerly used in several places, but that removes composition info.

;;*******************************************************************
;;**
;;**  Macros to parse the list
;;**
;;*******************************************************************

(defconst xml-undefined-entity "?"
  "What to substitute for undefined entities")

(defvar xml-entity-alist
  '(("lt"   . "<")
    ("gt"   . ">")
    ("apos" . "'")
    ("quot" . "\"")
    ("amp"  . "&"))
  "The defined entities.  Entities are added to this when the DTD is parsed.")

(defvar xml-sub-parser nil
  "Dynamically set this to a non-nil value if you want to parse an XML fragment.")

(defvar xml-validating-parser nil
  "Set to non-nil to get validity checking.")

(defsubst xml-node-name (node)
  "Return the tag associated with NODE.
Without namespace-aware parsing, the tag is a symbol.

With namespace-aware parsing, the tag is a cons of a string
representing the uri of the namespace with the local name of the
tag.  For example,

    <foo>

would be represented by

    '(\"\" . \"foo\")."

  (car node))

(defsubst xml-node-attributes (node)
  "Return the list of attributes of NODE.
The list can be nil."
  (nth 1 node))

(defsubst xml-node-children (node)
  "Return the list of children of NODE.
This is a list of nodes, and it can be nil."
  (cddr node))

(defun xml-get-children (node child-name)
  "Return the children of NODE whose tag is CHILD-NAME.
CHILD-NAME should match the value returned by `xml-node-name'."
  (let ((match ()))
    (dolist (child (xml-node-children node))
      (if (and (listp child)
               (equal (xml-node-name child) child-name))
          (push child match)))
    (nreverse match)))

(defun xml-get-attribute-or-nil (node attribute)
  "Get from NODE the value of ATTRIBUTE.
Return nil if the attribute was not found.

See also `xml-get-attribute'."
  (cdr (assoc attribute (xml-node-attributes node))))

(defsubst xml-get-attribute (node attribute)
  "Get from NODE the value of ATTRIBUTE.
An empty string is returned if the attribute was not found.

See also `xml-get-attribute-or-nil'."
  (or (xml-get-attribute-or-nil node attribute) ""))

;;*******************************************************************
;;**
;;**  Creating the list
;;**
;;*******************************************************************

;;;###autoload
(defun xml-parse-file (file &optional parse-dtd parse-ns)
  "Parse the well-formed XML file FILE.
If FILE is already visited, use its buffer and don't kill it.
Returns the top node with all its children.
If PARSE-DTD is non-nil, the DTD is parsed rather than skipped.
If PARSE-NS is non-nil, then QNAMES are expanded."
  (if (get-file-buffer file)
      (with-current-buffer (get-file-buffer file)
	(save-excursion
	  (xml-parse-region (point-min)
			    (point-max)
			    (current-buffer)
			    parse-dtd parse-ns)))
    (with-temp-buffer
      (insert-file-contents file)
      (xml-parse-region (point-min)
			(point-max)
			(current-buffer)
			parse-dtd parse-ns))))


(defvar xml-name-re)
(defvar xml-entity-value-re)
(defvar xml-att-def-re)
(let* ((start-chars (concat "[:alpha:]:_"))
       (name-chars  (concat "-[:digit:]." start-chars))
       ;;[3]   	S	   ::=   	(#x20 | #x9 | #xD | #xA)+
       (whitespace  "[ \t\n\r]"))
  ;;[4] NameStartChar ::= ":" | [A-Z] | "_" | [a-z] | [#xC0-#xD6] 
  ;;                      | [#xD8-#xF6] | [#xF8-#x2FF] | [#x370-#x37D] | [#x37F-#x1FFF]
  ;;                      | [#x200C-#x200D] | [#x2070-#x218F] | [#x2C00-#x2FEF] | [#x3001-#xD7FF]
  ;;                      | [#xF900-#xFDCF] | [#xFDF0-#xFFFD] | [#x10000-#xEFFFF]
  (defvar xml-name-start-char-re (concat "[" start-chars "]"))
  ;;[4a] NameChar	::= NameStartChar | "-" | "." | [0-9] | #xB7 | [#x0300-#x036F] | [#x203F-#x2040]
  (defvar xml-name-char-re       (concat "[" name-chars  "]"))
  ;;[5] Name     ::= NameStartChar (NameChar)*
  (defvar xml-name-re            (concat xml-name-start-char-re xml-name-char-re "*"))
  ;;[6] Names    ::= Name (#x20 Name)*
  (defvar xml-names-re           (concat xml-name-re "\\(?: " xml-name-re "\\)*"))
  ;;[7] Nmtoken ::= (NameChar)+
  (defvar xml-nmtoken-re         (concat xml-name-char-re "+"))
  ;;[8] Nmtokens ::= Nmtoken (#x20 Nmtoken)*
  (defvar xml-nmtokens-re        (concat xml-nmtoken-re "\\(?: " xml-name-re "\\)*"))
  ;;[66] CharRef ::= '&#' [0-9]+ ';' | '&#x' [0-9a-fA-F]+ ';'
  (defvar xml-char-ref-re        "\\(?:&#[0-9]+;\\|&#x[0-9a-fA-F]+;\\)")
  ;;[68] EntityRef   ::= '&' Name ';'
  (defvar xml-entity-ref         (concat "&" xml-name-re ";"))
  ;;[69] PEReference ::= '%' Name ';'
  (defvar xml-pe-reference-re    (concat "%" xml-name-re ";"))
  ;;[67] Reference   ::= EntityRef | CharRef
  (defvar xml-reference-re       (concat "\\(?:" xml-entity-ref "\\|" xml-char-ref-re "\\)"))
  ;;[10]   	AttValue	   ::=   	'"' ([^<&"] | Reference)* '"' |  "'" ([^<&'] | Reference)* "'"
  (defvar xml-att-value-re    (concat "\\(?:\"\\(?:[^&\"]\\|" xml-reference-re "\\)*\"\\|"
				      "'\\(?:[^&']\\|" xml-reference-re "\\)*'\\)"))
  ;;[56]   	TokenizedType	   ::=   	'ID'	   [VC: ID] [VC: One ID per Element Type] [VC: ID Attribute Default]
  ;;                                            | 'IDREF'    [VC: IDREF]
  ;;                             	              | 'IDREFS'   [VC: IDREF]
  ;;                                            | 'ENTITY'   [VC: Entity Name]
  ;;                                            | 'ENTITIES' [VC: Entity Name]
  ;;                                            | 'NMTOKEN'  [VC: Name Token]
  ;;                                            | 'NMTOKENS' [VC: Name Token]
  (defvar xml-tokenized-type-re "\\(?:ID\\|IDREF\\|IDREFS\\|ENTITY\\|ENTITIES\\|NMTOKEN\\|NMTOKENS\\)")
  ;;[58]   	NotationType	   ::=   	'NOTATION' S '(' S? Name (S? '|' S? Name)* S? ')'
  (defvar xml-notation-type-re (concat "\\(?:NOTATION" whitespace "(" whitespace "*" xml-name-re
				       "\\(?:" whitespace "*|" whitespace "*" xml-name-re "\\)*" whitespace "*)\\)"))
  ;;[59]   	Enumeration	   ::=   	'(' S? Nmtoken (S? '|' S? Nmtoken)* S? ')'	[VC: Enumeration] [VC: No Duplicate Tokens]
  (defvar xml-enumeration-re (concat "\\(?:(" whitespace "*" xml-nmtoken-re 
				     "\\(?:" whitespace "*|" whitespace "*" xml-nmtoken-re "\\)*"
				     whitespace ")\\)"))
  ;;[57]   	EnumeratedType	   ::=   	NotationType | Enumeration
  (defvar xml-enumerated-type-re (concat "\\(?:" xml-notation-type-re "\\|" xml-enumeration-re "\\)"))
  ;;[54]   	AttType	   ::=   	StringType | TokenizedType | EnumeratedType
  ;;[55]   	StringType	   ::=   	'CDATA'
  (defvar xml-att-type-re (concat "\\(?:CDATA\\|" xml-tokenized-type-re "\\|" xml-notation-type-re"\\|" xml-enumerated-type-re "\\)"))
  ;;[60]   	DefaultDecl	   ::=   	'#REQUIRED' | '#IMPLIED' | (('#FIXED' S)? AttValue)
  (defvar xml-default-decl-re (concat "\\(?:#REQUIRED\\|#IMPLIED\\|\\(?:#FIXED" whitespace "\\)*" xml-att-value-re "\\)"))
  ;;[53]   	AttDef	   ::=   	S Name S AttType S DefaultDecl
  (defvar xml-att-def-re         (concat "\\(?:" whitespace "*" xml-name-re
					 whitespace "*" xml-att-type-re
					 whitespace "*" xml-default-decl-re "\\)"))
  ;;[9] EntityValue ::= '"' ([^%&"] | PEReference | Reference)* '"'
  ;;		   |  "'" ([^%&'] | PEReference | Reference)* "'"
  (defvar xml-entity-value-re    (concat "\\(?:\"\\(?:[^%&\"]\\|" xml-pe-reference-re
					 "\\|" xml-reference-re "\\)*\"\\|'\\(?:[^%&']\\|"
					 xml-pe-reference-re "\\|" xml-reference-re "\\)*'\\)")))
;;[75] ExternalID ::= 'SYSTEM' S SystemLiteral
;;                 | 'PUBLIC' S PubidLiteral S SystemLiteral
;;[76] NDataDecl ::=   	S 'NDATA' S 
;;[73] EntityDef  ::= EntityValue| (ExternalID NDataDecl?)
;;[71] GEDecl     ::= '<!ENTITY' S Name S EntityDef S? '>'
;;[74] PEDef      ::= EntityValue | ExternalID
;;[72] PEDecl     ::= '<!ENTITY' S '%' S Name S PEDef S? '>'
;;[70] EntityDecl ::= GEDecl | PEDecl

;; Note that this is setup so that we can do whitespace-skipping with
;; `(skip-syntax-forward " ")', inter alia.  Previously this was slow
;; compared with `re-search-forward', but that has been fixed.  Also
;; note that the standard syntax table contains other characters with
;; whitespace syntax, like NBSP, but they are invalid in contexts in
;; which we might skip whitespace -- specifically, they're not
;; NameChars [XML 4].

(defvar xml-syntax-table
  (let ((table (make-syntax-table)))
    ;; Get space syntax correct per XML [3].
    (dotimes (c 31)
      (modify-syntax-entry c "." table)) ; all are space in standard table
    (dolist (c '(?\t ?\n ?\r))		 ; these should be space
      (modify-syntax-entry c " " table))
    ;; For skipping attributes.
    (modify-syntax-entry ?\" "\"" table)
    (modify-syntax-entry ?' "\"" table)
    ;; Non-alnum name chars should be symbol constituents (`-' and `_'
    ;; are OK by default).
    (modify-syntax-entry ?. "_" table)
    (modify-syntax-entry ?: "_" table)
    ;; XML [89]
    (unless (featurep 'xemacs)
      (dolist (c '(#x00B7 #x02D0 #x02D1 #x0387 #x0640 #x0E46 #x0EC6 #x3005
			  #x3031 #x3032 #x3033 #x3034 #x3035 #x309D #x309E #x30FC
			  #x30FD #x30FE))
	(modify-syntax-entry (decode-char 'ucs c) "w" table)))
    ;; Fixme: rest of [4]
    table)
  "Syntax table used by `xml-parse-region'.")

;; XML [5]
;; Note that [:alpha:] matches all multibyte chars with word syntax.
(eval-and-compile
  (defconst xml-name-regexp "[[:alpha:]_:][[:alnum:]._:-]*"))

;; Fixme:  This needs re-writing to deal with the XML grammar properly, i.e.
;;   document    ::=    prolog element Misc*
;;   prolog    ::=    XMLDecl? Misc* (doctypedecl Misc*)?

;;;###autoload
(defun xml-parse-region (beg end &optional buffer parse-dtd parse-ns)
  "Parse the region from BEG to END in BUFFER.
If BUFFER is nil, it defaults to the current buffer.
Returns the XML list for the region, or raises an error if the region
is not well-formed XML.
If PARSE-DTD is non-nil, the DTD is parsed rather than skipped,
and returned as the first element of the list.
If PARSE-NS is non-nil, then QNAMES are expanded."
  ;; Use fixed syntax table to ensure regexp char classes and syntax
  ;; specs DTRT.
  (with-syntax-table (standard-syntax-table)
    (let ((case-fold-search nil)	; XML is case-sensitive.
 	  xml result dtd)
      (save-excursion
 	(if buffer
 	    (set-buffer buffer))
 	(save-restriction
 	  (narrow-to-region beg end)
	  (goto-char (point-min))
	  (while (not (eobp))
	    (if (search-forward "<" nil t)
		(progn
		  (forward-char -1)
		  (setq result (xml-parse-tag parse-dtd parse-ns))
		  (if (and xml result (not xml-sub-parser))
		      ;;  translation of rule [1] of XML specifications
		      (error "XML: (Not Well-Formed) Only one root tag allowed")
		    (cond
		     ((null result))
		     ((and (listp (car result))
			   parse-dtd)
		      (setq dtd (car result))
		      (if (cdr result)	; possible leading comment
			  (add-to-list 'xml (cdr result))))
		     (t
		      (add-to-list 'xml result)))))
	      (goto-char (point-max))))
	  (if parse-dtd
	      (cons dtd (nreverse xml))
	    (nreverse xml)))))))

(defun xml-maybe-do-ns (name default xml-ns)
  "Perform any namespace expansion.
NAME is the name to perform the expansion on.
DEFAULT is the default namespace.  XML-NS is a cons of namespace
names to uris.  When namespace-aware parsing is off, then XML-NS
is nil.

During namespace-aware parsing, any name without a namespace is
put into the namespace identified by DEFAULT.  nil is used to
specify that the name shouldn't be given a namespace."
  (if (consp xml-ns)
      (let* ((nsp (string-match ":" name))
	     (lname (if nsp (substring name (match-end 0)) name))
	     (prefix (if nsp (substring name 0 (match-beginning 0)) default))
	     (special (and (string-equal lname "xmlns") (not prefix)))
             ;; Setting default to nil will insure that there is not
             ;; matching cons in xml-ns.  In which case we
	     (ns (or (cdr (assoc (if special "xmlns" prefix)
                                 xml-ns))
                     "")))
        (cons ns (if special "" lname)))
    (intern name)))

(defun xml-parse-fragment (&optional parse-dtd parse-ns)
  "Parse xml-like fragments."
  (let ((xml-sub-parser t)
	children)
    (while (not (eobp))
      (let ((bit (xml-parse-tag
		  parse-dtd parse-ns)))
	(if children
	    (setq children (append (list bit) children))
	  (if (stringp bit)
	      (setq children (list bit))
	    (setq children bit)))))
    (reverse children)))

(defun xml-parse-tag (&optional parse-dtd parse-ns)
  "Parse the tag at point.
If PARSE-DTD is non-nil, the DTD of the document, if any, is parsed and
returned as the first element in the list.
If PARSE-NS is non-nil, then QNAMES are expanded.
Returns one of:
 - a list : the matching node
 - nil    : the point is not looking at a tag.
 - a pair : the first element is the DTD, the second is the node."
  (let ((xml-validating-parser (or parse-dtd xml-validating-parser))
	(xml-ns (if (consp parse-ns)
		    parse-ns
		  (if parse-ns
		      (list
		       ;; Default for empty prefix is no namespace
		       (cons ""      "")
		       ;; "xml" namespace
		       (cons "xml"   "http://www.w3.org/XML/1998/namespace")
		       ;; We need to seed the xmlns namespace
		       (cons "xmlns" "http://www.w3.org/2000/xmlns/"))))))
    (cond
     ;; Processing instructions (like the <?xml version="1.0"?> tag at the
     ;; beginning of a document).
     ((looking-at "<\\?")
      (search-forward "?>")
      (skip-syntax-forward " ")
      (xml-parse-tag parse-dtd xml-ns))
     ;;  Character data (CDATA) sections, in which no tag should be interpreted
     ((looking-at "<!\\[CDATA\\[")
      (let ((pos (match-end 0)))
	(unless (search-forward "]]>" nil t)
	  (error "XML: (Not Well Formed) CDATA section does not end anywhere in the document"))
	(concat
	 (buffer-substring pos (match-beginning 0))
	 (xml-parse-string))))
     ;;  DTD for the document
     ((looking-at "<!DOCTYPE")
      (let ((dtd (xml-parse-dtd parse-ns)))
	(skip-syntax-forward " ")
	(if xml-validating-parser
	    (cons dtd (xml-parse-tag nil xml-ns))
	  (xml-parse-tag nil xml-ns))))
     ;;  skip comments
     ((looking-at "<!--")
      (search-forward "-->")
      nil)
     ;;  end tag
     ((looking-at "</")
      '())
     ;;  opening tag
     ((looking-at "<\\([^/>[:space:]]+\\)")
      (goto-char (match-end 1))

      ;; Parse this node
      (let* ((node-name (match-string 1))
	     ;; Parse the attribute list.
	     (attrs (xml-parse-attlist xml-ns))
	     children pos)

	;; add the xmlns:* attrs to our cache
	(when (consp xml-ns)
	  (dolist (attr attrs)
	    (when (and (consp (car attr))
		       (equal "http://www.w3.org/2000/xmlns/"
			      (caar attr)))
	      (push (cons (cdar attr) (cdr attr))
		    xml-ns))))

	(setq children (list attrs (xml-maybe-do-ns node-name "" xml-ns)))

	;; is this an empty element ?
	(if (looking-at "/>")
	    (progn
	      (forward-char 2)
	      (nreverse children))

	  ;; is this a valid start tag ?
	  (if (eq (char-after) ?>)
	      (progn
		(forward-char 1)
		;;  Now check that we have the right end-tag. Note that this
		;;  one might contain spaces after the tag name
		(let ((end (concat "</" node-name "\\s-*>")))
		  (while (not (looking-at end))
		    (cond
		     ((looking-at "</")
		      (error "XML: (Not Well-Formed) Invalid end tag (expecting %s) at pos %d"
			     node-name (point)))
		     ((= (char-after) ?<)
		      (let ((tag (xml-parse-tag nil xml-ns)))
			(when tag
			  (push tag children))))
		     (t
		      (let ((expansion (xml-parse-string)))
			(setq children
			      (if (stringp expansion)
				  (if (stringp (car children))
				      ;; The two strings were separated by a comment.
				      (setq children (append (list (concat (car children) expansion))
							     (cdr children)))
				    (setq children (append (list expansion) children)))
				(setq children (append expansion children))))))))

		  (goto-char (match-end 0))
		  (nreverse children)))
	    ;;  This was an invalid start tag (Expected ">", but didn't see it.)
	    (error "XML: (Well-Formed) Couldn't parse tag: %s"
		   (buffer-substring (- (point) 10) (+ (point) 1)))))))
     (t	;; (Not one of PI, CDATA, Comment, End tag, or Start tag)
      (unless xml-sub-parser		; Usually, we error out.
	(error "XML: (Well-Formed) Invalid character"))

      ;; However, if we're parsing incrementally, then we need to deal
      ;; with stray CDATA.
      (xml-parse-string)))))

(defun xml-parse-string ()
  "Parse the next whatever.  Could be a string, or an element."
  (let* ((pos (point))
	 (string (progn (if (search-forward "<" nil t)
			    (forward-char -1)
			  (goto-char (point-max)))
			(buffer-substring pos (point)))))
    ;; Clean up the string.  As per XML specifications, the XML
    ;; processor should always pass the whole string to the
    ;; application.  But \r's should be replaced:
    ;; http://www.w3.org/TR/2000/REC-xml-20001006#sec-line-ends
    (setq pos 0)
    (while (string-match "\r\n?" string pos)
      (setq string (replace-match "\n" t t string))
      (setq pos (1+ (match-beginning 0))))

    (xml-substitute-special string)))

(defun xml-parse-attlist (&optional xml-ns)
  "Return the attribute-list after point.
Leave point at the first non-blank character after the tag."
  (let ((attlist ())
	end-pos name)
    (skip-syntax-forward " ")
    (while (looking-at (eval-when-compile
			 (concat "\\(" xml-name-regexp "\\)\\s-*=\\s-*")))
      (setq end-pos (match-end 0))
      (setq name (xml-maybe-do-ns (match-string 1) nil xml-ns))
      (goto-char end-pos)

      ;; See also: http://www.w3.org/TR/2000/REC-xml-20001006#AVNormalize

      ;; Do we have a string between quotes (or double-quotes),
      ;;  or a simple word ?
      (if (looking-at "\"\\([^\"]*\\)\"")
	  (setq end-pos (match-end 0))
	(if (looking-at "'\\([^']*\\)'")
	    (setq end-pos (match-end 0))
	  (error "XML: (Not Well-Formed) Attribute values must be given between quotes")))

      ;; Each attribute must be unique within a given element
      (if (assoc name attlist)
	  (error "XML: (Not Well-Formed) Each attribute must be unique within an element"))

      ;; Multiple whitespace characters should be replaced with a single one
      ;; in the attributes
      (let ((string (match-string 1))
	    (pos 0))
	(replace-regexp-in-string "\\s-\\{2,\\}" " " string)
	(let ((expansion (xml-substitute-special string)))
	  (unless (stringp expansion)
					; We say this is the constraint.  It is acctually that
					; external entities nor "<" can be in an attribute value.
	    (error "XML: (Not Well-Formed) Entities in attributes cannot expand into elements"))
	  (push (cons name expansion) attlist)))

      (goto-char end-pos)
      (skip-syntax-forward " "))
    (nreverse attlist)))

;;*******************************************************************
;;**
;;**  The DTD (document type declaration)
;;**  The following functions know how to skip or parse the DTD of
;;**  a document
;;**
;;*******************************************************************

;; Fixme: This fails at least if the DTD contains conditional sections.

(defun xml-skip-dtd ()
  "Skip the DTD at point.
This follows the rule [28] in the XML specifications."
  (let ((xml-validating-parser nil))
    (xml-parse-dtd)))

(defun xml-parse-dtd (&optional parse-ns)
  "Parse the DTD at point."
  (forward-char (eval-when-compile (length "<!DOCTYPE")))
  (skip-syntax-forward " ")
  (if (and (looking-at ">")
	   xml-validating-parser)
      (error "XML: (Validity) Invalid DTD (expecting name of the document)"))

  ;;  Get the name of the document
  (looking-at xml-name-regexp)
  (let ((dtd (list (match-string 0) 'dtd))
	type element end-pos)
    (goto-char (match-end 0))

    (skip-syntax-forward " ")
    ;; XML [75]
    (cond ((looking-at "PUBLIC\\s-+")
	   (goto-char (match-end 0))
	   (unless (or (re-search-forward
			"\\=\"\\([[:space:][:alnum:]-'()+,./:=?;!*#@$_%]*\\)\""
			nil t)
		       (re-search-forward
			"\\='\\([[:space:][:alnum:]-()+,./:=?;!*#@$_%]*\\)'"
			nil t))
	     (error "XML: Missing Public ID"))
	   (let ((pubid (match-string 1)))
	     (skip-syntax-forward " ")
	     (unless (or (re-search-forward "\\='\\([^']*\\)'" nil t)
			 (re-search-forward "\\=\"\\([^\"]*\\)\"" nil t))
	       (error "XML: Missing System ID"))
	     (push (list pubid (match-string 1) 'public) dtd)))
	  ((looking-at "SYSTEM\\s-+")
	   (goto-char (match-end 0))
	   (unless (or (re-search-forward "\\='\\([^']*\\)'" nil t)
		       (re-search-forward "\\=\"\\([^\"]*\\)\"" nil t))
	     (error "XML: Missing System ID"))
	   (push (list (match-string 1) 'system) dtd)))
    (skip-syntax-forward " ")
    (if (eq ?> (char-after))
	(forward-char)
      (if (not (eq (char-after) ?\[))
	  (error "XML: Bad DTD")
	(forward-char)
	;;  Parse the rest of the DTD
	;;  Fixme: Deal with NOTATION, PIs.
	(while (not (looking-at "\\s-*\\]"))
	  (skip-syntax-forward " ")
	  (cond

	   ;;  Translation of rule [45] of XML specifications
	   ((looking-at
	     "<!ELEMENT\\s-+\\([[:alnum:].%;]+\\)\\s-+\\([^>]+\\)>")

	    (setq element (match-string 1)
		  type    (match-string-no-properties 2))
	    (setq end-pos (match-end 0))

	    ;;  Translation of rule [46] of XML specifications
	    (cond
	     ((string-match "^EMPTY[ \t\n\r]*$" type) ;; empty declaration
	      (setq type 'empty))
	     ((string-match "^ANY[ \t\n\r]*$" type) ;; any type of contents
	      (setq type 'any))
	     ((string-match "^(\\(.*\\))[ \t\n\r]*$" type) ;; children ([47])
	      (setq type (xml-parse-elem-type (match-string 1 type))))
	     ((string-match "^%[^;]+;[ \t\n\r]*$" type)	;; substitution
	      nil)
	     (t
	      (if xml-validating-parser 
		  (error "XML: (Validity) Invalid element type in the DTD"))))

	    ;;  rule [45]: the element declaration must be unique
	    (if (and (assoc element dtd)
		     xml-validating-parser)
		(error "XML: (Validity) Element declarations must be unique in a DTD (<%s>)"
		       element))

	    ;;  Store the element in the DTD
	    (push (list element type) dtd)
	    (goto-char end-pos))

	   ;; Translation of rule [52] of XML specifications
	   ((looking-at (concat "<!ATTLIST[ \t\n\r]*\\(" xml-name-re
				"\\)[ \t\n\r]*\\(" xml-att-def-re
				"\\)*[ \t\n\r]*>"))

	    ;; We don't do anything with ATTLIST currently
	    (goto-char (match-end 0)))

	   ((looking-at "<!--")
	    (search-forward "-->"))
	   ((looking-at (concat "<!ENTITY[ \t\n\r]*\\(" xml-name-re
				"\\)[ \t\n\r]*\\(" xml-entity-value-re
				"\\)[ \t\n\r]*>"))
	    (let ((name  (match-string 1))
		  (value (substring (match-string 2) 1
				    (- (length (match-string 2)) 1))))
	      (goto-char (match-end 0))
	      (setq xml-entity-alist
		    (append xml-entity-alist
			    (list (cons name 
					(with-temp-buffer
					  (insert value)
					  (goto-char (point-min))
					  (xml-parse-fragment
					   xml-validating-parser
					   parse-ns))))))))
	   ((or (looking-at (concat "<!ENTITY[ \t\n\r]+\\(" xml-name-re
				    "\\)[ \t\n\r]+SYSTEM[ \t\n\r]+"
				    "\\(\"[^\"]*\"\\|'[^']*'\\)[ \t\n\r]*>"))
		(looking-at (concat "<!ENTITY[ \t\n\r]+\\(" xml-name-re
				    "\\)[ \t\n\r]+PUBLIC[ \t\n\r]+"
				    "\"[- \r\na-zA-Z0-9'()+,./:=?;!*#@$_%]*\""
				    "\\|'[- \r\na-zA-Z0-9()+,./:=?;!*#@$_%]*'"
				    "[ \t\n\r]+\\(\"[^\"]*\"\\|'[^']*'\\)"
				    "[ \t\n\r]*>")))
	    (let ((name  (match-string 1))
		  (file  (substring (match-string 2) 1
				    (- (length (match-string 2)) 1))))
	      (goto-char (match-end 0))
	      (setq xml-entity-alist
		    (append xml-entity-alist
			    (list (cons name (with-temp-buffer
					       (insert-file-contents file)
					       (goto-char (point-min))
					       (xml-parse-fragment
						xml-validating-parser
						parse-ns))))))))
	   ;; skip parameter entity declarations
	   ((or (looking-at (concat "<!ENTITY[ \t\n\r]+%[ \t\n\r]+\\(" xml-name-re
				    "\\)[ \t\n\r]+SYSTEM[ \t\n\r]+"
				    "\\(\"[^\"]*\"\\|'[^']*'\\)[ \t\n\r]*>"))
		(looking-at (concat "<!ENTITY[ \t\n\r]+"
				    "%[ \t\n\r]+"
				    "\\(" xml-name-re "\\)[ \t\n\r]+"
				    "PUBLIC[ \t\n\r]+"
				    "\\(\"[- \r\na-zA-Z0-9'()+,./:=?;!*#@$_%]*\""
				    "\\|'[- \r\na-zA-Z0-9()+,./:=?;!*#@$_%]*'\\)[ \t\n\r]+"
				    "\\(\"[^\"]+\"\\|'[^']+'\\)"
				    "[ \t\n\r]*>")))
	    (goto-char (match-end 0)))
	   ;; skip parameter entities
	   ((looking-at (concat "%" xml-name-re ";"))
	    (goto-char (match-end 0)))
	   (t
	    (when xml-validating-parser
	      (error "XML: (Validity) Invalid DTD item"))))))
      (if (looking-at "\\s-*]>")
	  (goto-char (match-end 0))))
    (nreverse dtd)))

(defun xml-parse-elem-type (string)
  "Convert element type STRING into a Lisp structure."

  (let (elem modifier)
    (if (string-match "(\\([^)]+\\))\\([+*?]?\\)" string)
	(progn
	  (setq elem     (match-string 1 string)
		modifier (match-string 2 string))
	  (if (string-match "|" elem)
	      (setq elem (cons 'choice
			       (mapcar 'xml-parse-elem-type
				       (split-string elem "|"))))
	    (if (string-match "," elem)
		(setq elem (cons 'seq
				 (mapcar 'xml-parse-elem-type
					 (split-string elem ",")))))))
      (if (string-match "[ \t\n\r]*\\([^+*?]+\\)\\([+*?]?\\)" string)
	  (setq elem	 (match-string 1 string)
		modifier (match-string 2 string))))

    (if (and (stringp elem) (string= elem "#PCDATA"))
	(setq elem 'pcdata))

    (cond
     ((string= modifier "+")
      (list '+ elem))
     ((string= modifier "*")
      (list '* elem))
     ((string= modifier "?")
      (list '\? elem))
     (t
      elem))))

;;*******************************************************************
;;**
;;**  Substituting special XML sequences
;;**
;;*******************************************************************

(defun xml-substitute-special (string)
  "Return STRING, after subsituting entity references."
  ;; This originally made repeated passes through the string from the
  ;; beginning, which isn't correct, since then either "&amp;amp;" or
  ;; "&#38;amp;" won't DTRT.

  (let ((point 0)
	children end-point)
    (while (string-match "&\\([^;]*\\);" string point)
      (setq end-point (match-end 0))
      (let* ((this-part (match-string 1 string))
	     (prev-part (substring string point (match-beginning 0)))
	     (entity (assoc this-part xml-entity-alist))
	     (expansion 
	      (cond ((string-match "#\\([0-9]+\\)" this-part)
		     (let ((c (decode-char
			       'ucs
			       (string-to-number (match-string 1 this-part)))))
		       (if c (string c))))
		    ((string-match "#x\\([[:xdigit:]]+\\)" this-part)
		     (let ((c (decode-char
			       'ucs
			       (string-to-number (match-string 1 this-part) 16))))
		       (if c (string c))))
		    (entity
		     (cdr entity))
		    ((eq (length this-part) 0)
		     (error "XML: (Not Well-Formed) No entity given"))
		    (t
		     (if xml-validating-parser
			 (error "XML: (Validity) Undefined entity `%s'"
				this-part)
		       xml-undefined-entity)))))

	(cond ((null children)
	       ;; FIXME: If we have an entity that expands into XML, this won't work.
	       (setq children
		     (concat prev-part expansion)))
	      ((stringp children)
	       (if (stringp expansion)
		   (setq children (concat children prev-part expansion))
		 (setq children (list expansion (concat prev-part children)))))
	      ((and (stringp expansion)
		    (stringp (car children)))
	       (setcar children (concat prev-part expansion (car children))))
	      ((stringp expansion)
	       (setq children (append (concat prev-part expansion)
				      children)))
	      ((stringp (car children))
	       (setcar children (concat (car children) prev-part))
	       (setq children (append expansion children)))
	      (t
	       (setq children (list expansion
				    prev-part
				    children))))
	(setq point end-point)))
    (cond ((stringp children)
	   (concat children (substring string point)))
	  ((stringp (car (last children)))
	   (concat (car (last children)) (substring string point)))
	  ((null children)
	   string)
	  (t
	   (concat (mapconcat 'identity
			      (nreverse children)
			      "")
		   (substring string point))))))

;;*******************************************************************
;;**
;;**  Printing a tree.
;;**  This function is intended mainly for debugging purposes.
;;**
;;*******************************************************************

(defun xml-debug-print (xml &optional indent-string)
  "Outputs the XML in the current buffer.
XML can be a tree or a list of nodes.
The first line is indented with the optional INDENT-STRING."
  (setq indent-string (or indent-string ""))
  (dolist (node xml)
    (xml-debug-print-internal node indent-string)))

(defalias 'xml-print 'xml-debug-print)

(defun xml-debug-print-internal (xml indent-string)
  "Outputs the XML tree in the current buffer.
The first line is indented with INDENT-STRING."
  (let ((tree xml)
	attlist)
    (insert indent-string ?< (symbol-name (xml-node-name tree)))

    ;;  output the attribute list
    (setq attlist (xml-node-attributes tree))
    (while attlist
      (insert ?\  (symbol-name (caar attlist)) "=\"" (cdar attlist) ?\")
      (setq attlist (cdr attlist)))

    (setq tree (xml-node-children tree))

    (if (null tree)
	(insert ?/ ?>)
      (insert ?>)

      ;;  output the children
      (dolist (node tree)
	(cond
	 ((listp node)
	  (insert ?\n)
	  (xml-debug-print-internal node (concat indent-string "  ")))
	 ((stringp node) (insert node))
	 (t
	  (error "Invalid XML tree"))))

      (when (not (and (null (cdr tree))
		      (stringp (car tree))))
	(insert ?\n indent-string))
      (insert ?< ?/ (symbol-name (xml-node-name xml)) ?>))))

(provide 'xml)

;; arch-tag: 5864b283-5a68-4b59-a20d-36a72b353b9b
;;; xml.el ends here