lisp/xml.el

   1 ;;; xml.el --- XML parser
   2
   3 ;; Copyright (C) 2000, 2001, 2002, 2003, 2004,
   4 ;;   2005, 2006 Free Software Foundation, Inc.
   5
   6 ;; Author: Emmanuel Briot  <briot@gnat.com>
   7 ;; Maintainer: Mark A. Hershberger <mah@everybody.org>
   8 ;; Keywords: xml, data
   9
  10 ;; This file is part of GNU Emacs.
  11
  12 ;; GNU Emacs is free software; you can redistribute it and/or modify
  13 ;; it under the terms of the GNU General Public License as published by
  14 ;; the Free Software Foundation; either version 2, or (at your option)
  15 ;; any later version.
  16
  17 ;; GNU Emacs is distributed in the hope that it will be useful,
  18 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  19 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20 ;; GNU General Public License for more details.
  21
  22 ;; You should have received a copy of the GNU General Public License
  23 ;; along with GNU Emacs; see the file COPYING.  If not, write to the
  24 ;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  25 ;; Boston, MA 02110-1301, USA.
  26
  27 ;;; Commentary:
  28
  29 ;; This file contains a somewhat incomplete non-validating XML parser.  It
  30 ;; parses a file, and returns a list that can be used internally by
  31 ;; any other Lisp libraries.
  32
  33 ;;; FILE FORMAT
  34
  35 ;; The document type declaration may either be ignored or (optionally)
  36 ;; parsed, but currently the parsing will only accept element
  37 ;; declarations.  The XML file is assumed to be well-formed.  In case
  38 ;; of error, the parsing stops and the XML file is shown where the
  39 ;; parsing stopped.
  40 ;;
  41 ;; It also knows how to ignore comments and processing instructions.
  42 ;;
  43 ;; The XML file should have the following format:
  44 ;;    <node1 attr1="name1" attr2="name2" ...>value
  45 ;;       <node2 attr3="name3" attr4="name4">value2</node2>
  46 ;;       <node3 attr5="name5" attr6="name6">value3</node3>
  47 ;;    </node1>
  48 ;; Of course, the name of the nodes and attributes can be anything.  There can
  49 ;; be any number of attributes (or none), as well as any number of children
  50 ;; below the nodes.
  51 ;;
  52 ;; There can be only top level node, but with any number of children below.
  53
  54 ;;; LIST FORMAT
  55
  56 ;; The functions `xml-parse-file', `xml-parse-region' and
  57 ;; `xml-parse-tag' return a list with the following format:
  58 ;;
  59 ;;    xml-list   ::= (node node ...)
  60 ;;    node       ::= (qname attribute-list . child_node_list)
  61 ;;    child_node_list ::= child_node child_node ...
  62 ;;    child_node ::= node | string
  63 ;;    qname      ::= (:namespace-uri . "name") | "name"
  64 ;;    attribute_list ::= ((qname . "value") (qname . "value") ...)
  65 ;;                       | nil
  66 ;;    string     ::= "..."
  67 ;;
  68 ;; Some macros are provided to ease the parsing of this list.
  69 ;; Whitespace is preserved.  Fixme: There should be a tree-walker that
  70 ;; can remove it.
  71
  72 ;; TODO:
  73 ;;  * xml:base, xml:space support
  74 ;;  * more complete DOCTYPE parsing
  75 ;;  * pi support
  76
  77 ;;; Code:
  78
  79 ;; Note that {buffer-substring,match-string}-no-properties were
  80 ;; formerly used in several places, but that removes composition info.
  81
  82 ;;*******************************************************************
  83 ;;**
  84 ;;**  Macros to parse the list
  85 ;;**
  86 ;;*******************************************************************
  87
  88 (defconst xml-undefined-entity "?"
  89   "What to substitute for undefined entities")
  90
  91 (defvar xml-entity-alist
  92   '(("lt"   . "<")
  93     ("gt"   . ">")
  94     ("apos" . "'")
  95     ("quot" . "\"")
  96     ("amp"  . "&"))
  97   "The defined entities.  Entities are added to this when the DTD is parsed.")
  98
  99 (defvar xml-sub-parser nil
 100   "Dynamically set this to a non-nil value if you want to parse an XML fragment.")
 101
 102 (defvar xml-validating-parser nil
 103   "Set to non-nil to get validity checking.")
 104
 105 (defsubst xml-node-name (node)
 106   "Return the tag associated with NODE.
 107 Without namespace-aware parsing, the tag is a symbol.
 108
 109 With namespace-aware parsing, the tag is a cons of a string
 110 representing the uri of the namespace with the local name of the
 111 tag.  For example,
 112
 113     <foo>
 114
 115 would be represented by
 116
 117     '(\"\" . \"foo\")."
 118
 119   (car node))
 120
 121 (defsubst xml-node-attributes (node)
 122   "Return the list of attributes of NODE.
 123 The list can be nil."
 124   (nth 1 node))
 125
 126 (defsubst xml-node-children (node)
 127   "Return the list of children of NODE.
 128 This is a list of nodes, and it can be nil."
 129   (cddr node))
 130
 131 (defun xml-get-children (node child-name)
 132   "Return the children of NODE whose tag is CHILD-NAME.
 133 CHILD-NAME should match the value returned by `xml-node-name'."
 134   (let ((match ()))
 135     (dolist (child (xml-node-children node))
 136       (if (and (listp child)
 137                (equal (xml-node-name child) child-name))
 138           (push child match)))
 139     (nreverse match)))
 140
 141 (defun xml-get-attribute-or-nil (node attribute)
 142   "Get from NODE the value of ATTRIBUTE.
 143 Return nil if the attribute was not found.
 144
 145 See also `xml-get-attribute'."
 146   (cdr (assoc attribute (xml-node-attributes node))))
 147
 148 (defsubst xml-get-attribute (node attribute)
 149   "Get from NODE the value of ATTRIBUTE.
 150 An empty string is returned if the attribute was not found.
 151
 152 See also `xml-get-attribute-or-nil'."
 153   (or (xml-get-attribute-or-nil node attribute) ""))
 154
 155 ;;*******************************************************************
 156 ;;**
 157 ;;**  Creating the list
 158 ;;**
 159 ;;*******************************************************************
 160
 161 ;;;###autoload
 162 (defun xml-parse-file (file &optional parse-dtd parse-ns)
 163   "Parse the well-formed XML file FILE.
 164 If FILE is already visited, use its buffer and don't kill it.
 165 Returns the top node with all its children.
 166 If PARSE-DTD is non-nil, the DTD is parsed rather than skipped.
 167 If PARSE-NS is non-nil, then QNAMES are expanded."
 168   (if (get-file-buffer file)
 169       (with-current-buffer (get-file-buffer file)
 170         (save-excursion
 171           (xml-parse-region (point-min)
 172                             (point-max)
 173                             (current-buffer)
 174                             parse-dtd parse-ns)))
 175     (with-temp-buffer
 176       (insert-file-contents file)
 177       (xml-parse-region (point-min)
 178                         (point-max)
 179                         (current-buffer)
 180                         parse-dtd parse-ns))))
 181
 182
 183 (defvar xml-name-re)
 184 (defvar xml-entity-value-re)
 185 (defvar xml-att-def-re)
 186 (let* ((start-chars (concat "[:alpha:]:_"))
 187        (name-chars  (concat "-[:digit:]." start-chars))
 188        ;;[3]    S          ::=          (#x20 | #x9 | #xD | #xA)+
 189        (whitespace  "[ \t\n\r]"))
 190   ;;[4] NameStartChar ::= ":" | [A-Z] | "_" | [a-z] | [#xC0-#xD6]
 191   ;;                      | [#xD8-#xF6] | [#xF8-#x2FF] | [#x370-#x37D] | [#x37F-#x1FFF]
 192   ;;                      | [#x200C-#x200D] | [#x2070-#x218F] | [#x2C00-#x2FEF] | [#x3001-#xD7FF]
 193   ;;                      | [#xF900-#xFDCF] | [#xFDF0-#xFFFD] | [#x10000-#xEFFFF]
 194   (defvar xml-name-start-char-re (concat "[" start-chars "]"))
 195   ;;[4a] NameChar       ::= NameStartChar | "-" | "." | [0-9] | #xB7 | [#x0300-#x036F] | [#x203F-#x2040]
 196   (defvar xml-name-char-re       (concat "[" name-chars  "]"))
 197   ;;[5] Name     ::= NameStartChar (NameChar)*
 198   (defvar xml-name-re            (concat xml-name-start-char-re xml-name-char-re "*"))
 199   ;;[6] Names    ::= Name (#x20 Name)*
 200   (defvar xml-names-re           (concat xml-name-re "\\(?: " xml-name-re "\\)*"))
 201   ;;[7] Nmtoken ::= (NameChar)+
 202   (defvar xml-nmtoken-re         (concat xml-name-char-re "+"))
 203   ;;[8] Nmtokens ::= Nmtoken (#x20 Nmtoken)*
 204   (defvar xml-nmtokens-re        (concat xml-nmtoken-re "\\(?: " xml-name-re "\\)*"))
 205   ;;[66] CharRef ::= '&#' [0-9]+ ';' | '&#x' [0-9a-fA-F]+ ';'
 206   (defvar xml-char-ref-re        "\\(?:&#[0-9]+;\\|&#x[0-9a-fA-F]+;\\)")
 207   ;;[68] EntityRef   ::= '&' Name ';'
 208   (defvar xml-entity-ref         (concat "&" xml-name-re ";"))
 209   ;;[69] PEReference ::= '%' Name ';'
 210   (defvar xml-pe-reference-re    (concat "%" xml-name-re ";"))
 211   ;;[67] Reference   ::= EntityRef | CharRef
 212   (defvar xml-reference-re       (concat "\\(?:" xml-entity-ref "\\|" xml-char-ref-re "\\)"))
 213   ;;[10]        AttValue           ::=          '"' ([^<&"] | Reference)* '"' |  "'" ([^<&'] | Reference)* "'"
 214   (defvar xml-att-value-re    (concat "\\(?:\"\\(?:[^&\"]\\|" xml-reference-re "\\)*\"\\|"
 215                                       "'\\(?:[^&']\\|" xml-reference-re "\\)*'\\)"))
 216   ;;[56]        TokenizedType      ::=          'ID'       [VC: ID] [VC: One ID per Element Type] [VC: ID Attribute Default]
 217   ;;                                            | 'IDREF'    [VC: IDREF]
 218   ;;                                                  | 'IDREFS'   [VC: IDREF]
 219   ;;                                            | 'ENTITY'   [VC: Entity Name]
 220   ;;                                            | 'ENTITIES' [VC: Entity Name]
 221   ;;                                            | 'NMTOKEN'  [VC: Name Token]
 222   ;;                                            | 'NMTOKENS' [VC: Name Token]
 223   (defvar xml-tokenized-type-re "\\(?:ID\\|IDREF\\|IDREFS\\|ENTITY\\|ENTITIES\\|NMTOKEN\\|NMTOKENS\\)")
 224   ;;[58]        NotationType       ::=          'NOTATION' S '(' S? Name (S? '|' S? Name)* S? ')'
 225   (defvar xml-notation-type-re (concat "\\(?:NOTATION" whitespace "(" whitespace "*" xml-name-re
 226                                        "\\(?:" whitespace "*|" whitespace "*" xml-name-re "\\)*" whitespace "*)\\)"))
 227   ;;[59]        Enumeration        ::=          '(' S? Nmtoken (S? '|' S? Nmtoken)* S? ')'      [VC: Enumeration] [VC: No Duplicate Tokens]
 228   (defvar xml-enumeration-re (concat "\\(?:(" whitespace "*" xml-nmtoken-re
 229                                      "\\(?:" whitespace "*|" whitespace "*" xml-nmtoken-re "\\)*"
 230                                      whitespace ")\\)"))
 231   ;;[57]        EnumeratedType     ::=          NotationType | Enumeration
 232   (defvar xml-enumerated-type-re (concat "\\(?:" xml-notation-type-re "\\|" xml-enumeration-re "\\)"))
 233   ;;[54]        AttType    ::=          StringType | TokenizedType | EnumeratedType
 234   ;;[55]        StringType         ::=          'CDATA'
 235   (defvar xml-att-type-re (concat "\\(?:CDATA\\|" xml-tokenized-type-re "\\|" xml-notation-type-re"\\|" xml-enumerated-type-re "\\)"))
 236   ;;[60]        DefaultDecl        ::=          '#REQUIRED' | '#IMPLIED' | (('#FIXED' S)? AttValue)
 237   (defvar xml-default-decl-re (concat "\\(?:#REQUIRED\\|#IMPLIED\\|\\(?:#FIXED" whitespace "\\)*" xml-att-value-re "\\)"))
 238   ;;[53]        AttDef     ::=          S Name S AttType S DefaultDecl
 239   (defvar xml-att-def-re         (concat "\\(?:" whitespace "*" xml-name-re
 240                                          whitespace "*" xml-att-type-re
 241                                          whitespace "*" xml-default-decl-re "\\)"))
 242   ;;[9] EntityValue ::= '"' ([^%&"] | PEReference | Reference)* '"'
 243   ;;               |  "'" ([^%&'] | PEReference | Reference)* "'"
 244   (defvar xml-entity-value-re    (concat "\\(?:\"\\(?:[^%&\"]\\|" xml-pe-reference-re
 245                                          "\\|" xml-reference-re "\\)*\"\\|'\\(?:[^%&']\\|"
 246                                          xml-pe-reference-re "\\|" xml-reference-re "\\)*'\\)")))
 247 ;;[75] ExternalID ::= 'SYSTEM' S SystemLiteral
 248 ;;                 | 'PUBLIC' S PubidLiteral S SystemLiteral
 249 ;;[76] NDataDecl ::=    S 'NDATA' S
 250 ;;[73] EntityDef  ::= EntityValue| (ExternalID NDataDecl?)
 251 ;;[71] GEDecl     ::= '<!ENTITY' S Name S EntityDef S? '>'
 252 ;;[74] PEDef      ::= EntityValue | ExternalID
 253 ;;[72] PEDecl     ::= '<!ENTITY' S '%' S Name S PEDef S? '>'
 254 ;;[70] EntityDecl ::= GEDecl | PEDecl
 255
 256 ;; Note that this is setup so that we can do whitespace-skipping with
 257 ;; `(skip-syntax-forward " ")', inter alia.  Previously this was slow
 258 ;; compared with `re-search-forward', but that has been fixed.  Also
 259 ;; note that the standard syntax table contains other characters with
 260 ;; whitespace syntax, like NBSP, but they are invalid in contexts in
 261 ;; which we might skip whitespace -- specifically, they're not
 262 ;; NameChars [XML 4].
 263
 264 (defvar xml-syntax-table
 265   (let ((table (make-syntax-table)))
 266     ;; Get space syntax correct per XML [3].
 267     (dotimes (c 31)
 268       (modify-syntax-entry c "." table)) ; all are space in standard table
 269     (dolist (c '(?\t ?\n ?\r))           ; these should be space
 270       (modify-syntax-entry c " " table))
 271     ;; For skipping attributes.
 272     (modify-syntax-entry ?\" "\"" table)
 273     (modify-syntax-entry ?' "\"" table)
 274     ;; Non-alnum name chars should be symbol constituents (`-' and `_'
 275     ;; are OK by default).
 276     (modify-syntax-entry ?. "_" table)
 277     (modify-syntax-entry ?: "_" table)
 278     ;; XML [89]
 279     (unless (featurep 'xemacs)
 280       (dolist (c '(#x00B7 #x02D0 #x02D1 #x0387 #x0640 #x0E46 #x0EC6 #x3005
 281                           #x3031 #x3032 #x3033 #x3034 #x3035 #x309D #x309E #x30FC
 282                           #x30FD #x30FE))
 283         (modify-syntax-entry (decode-char 'ucs c) "w" table)))
 284     ;; Fixme: rest of [4]
 285     table)
 286   "Syntax table used by `xml-parse-region'.")
 287
 288 ;; XML [5]
 289 ;; Note that [:alpha:] matches all multibyte chars with word syntax.
 290 (eval-and-compile
 291   (defconst xml-name-regexp "[[:alpha:]_:][[:alnum:]._:-]*"))
 292
 293 ;; Fixme:  This needs re-writing to deal with the XML grammar properly, i.e.
 294 ;;   document    ::=    prolog element Misc*
 295 ;;   prolog    ::=    XMLDecl? Misc* (doctypedecl Misc*)?
 296
 297 ;;;###autoload
 298 (defun xml-parse-region (beg end &optional buffer parse-dtd parse-ns)
 299   "Parse the region from BEG to END in BUFFER.
 300 If BUFFER is nil, it defaults to the current buffer.
 301 Returns the XML list for the region, or raises an error if the region
 302 is not well-formed XML.
 303 If PARSE-DTD is non-nil, the DTD is parsed rather than skipped,
 304 and returned as the first element of the list.
 305 If PARSE-NS is non-nil, then QNAMES are expanded."
 306   ;; Use fixed syntax table to ensure regexp char classes and syntax
 307   ;; specs DTRT.
 308   (with-syntax-table (standard-syntax-table)
 309     (let ((case-fold-search nil)        ; XML is case-sensitive.
 310           xml result dtd)
 311       (save-excursion
 312         (if buffer
 313             (set-buffer buffer))
 314         (save-restriction
 315           (narrow-to-region beg end)
 316           (goto-char (point-min))
 317           (while (not (eobp))
 318             (if (search-forward "<" nil t)
 319                 (progn
 320                   (forward-char -1)
 321                   (setq result (xml-parse-tag parse-dtd parse-ns))
 322                   (if (and xml result (not xml-sub-parser))
 323                       ;;  translation of rule [1] of XML specifications
 324                       (error "XML: (Not Well-Formed) Only one root tag allowed")
 325                     (cond
 326                      ((null result))
 327                      ((and (listp (car result))
 328                            parse-dtd)
 329                       (setq dtd (car result))
 330                       (if (cdr result)  ; possible leading comment
 331                           (add-to-list 'xml (cdr result))))
 332                      (t
 333                       (add-to-list 'xml result)))))
 334               (goto-char (point-max))))
 335           (if parse-dtd
 336               (cons dtd (nreverse xml))
 337             (nreverse xml)))))))
 338
 339 (defun xml-maybe-do-ns (name default xml-ns)
 340   "Perform any namespace expansion.
 341 NAME is the name to perform the expansion on.
 342 DEFAULT is the default namespace.  XML-NS is a cons of namespace
 343 names to uris.  When namespace-aware parsing is off, then XML-NS
 344 is nil.
 345
 346 During namespace-aware parsing, any name without a namespace is
 347 put into the namespace identified by DEFAULT.  nil is used to
 348 specify that the name shouldn't be given a namespace."
 349   (if (consp xml-ns)
 350       (let* ((nsp (string-match ":" name))
 351              (lname (if nsp (substring name (match-end 0)) name))
 352              (prefix (if nsp (substring name 0 (match-beginning 0)) default))
 353              (special (and (string-equal lname "xmlns") (not prefix)))
 354              ;; Setting default to nil will insure that there is not
 355              ;; matching cons in xml-ns.  In which case we
 356              (ns (or (cdr (assoc (if special "xmlns" prefix)
 357                                  xml-ns))
 358                      "")))
 359         (cons ns (if special "" lname)))
 360     (intern name)))
 361
 362 (defun xml-parse-fragment (&optional parse-dtd parse-ns)
 363   "Parse xml-like fragments."
 364   (let ((xml-sub-parser t)
 365         children)
 366     (while (not (eobp))
 367       (let ((bit (xml-parse-tag
 368                   parse-dtd parse-ns)))
 369         (if children
 370             (setq children (append (list bit) children))
 371           (if (stringp bit)
 372               (setq children (list bit))
 373             (setq children bit)))))
 374     (reverse children)))
 375
 376 (defun xml-parse-tag (&optional parse-dtd parse-ns)
 377   "Parse the tag at point.
 378 If PARSE-DTD is non-nil, the DTD of the document, if any, is parsed and
 379 returned as the first element in the list.
 380 If PARSE-NS is non-nil, then QNAMES are expanded.
 381 Returns one of:
 382  - a list : the matching node
 383  - nil    : the point is not looking at a tag.
 384  - a pair : the first element is the DTD, the second is the node."
 385   (let ((xml-validating-parser (or parse-dtd xml-validating-parser))
 386         (xml-ns (if (consp parse-ns)
 387                     parse-ns
 388                   (if parse-ns
 389                       (list
 390                        ;; Default for empty prefix is no namespace
 391                        (cons ""      "")
 392                        ;; "xml" namespace
 393                        (cons "xml"   "http://www.w3.org/XML/1998/namespace")
 394                        ;; We need to seed the xmlns namespace
 395                        (cons "xmlns" "http://www.w3.org/2000/xmlns/"))))))
 396     (cond
 397      ;; Processing instructions (like the <?xml version="1.0"?> tag at the
 398      ;; beginning of a document).
 399      ((looking-at "<\\?")
 400       (search-forward "?>")
 401       (skip-syntax-forward " ")
 402       (xml-parse-tag parse-dtd xml-ns))
 403      ;;  Character data (CDATA) sections, in which no tag should be interpreted
 404      ((looking-at "<!\\[CDATA\\[")
 405       (let ((pos (match-end 0)))
 406         (unless (search-forward "]]>" nil t)
 407           (error "XML: (Not Well Formed) CDATA section does not end anywhere in the document"))
 408         (concat
 409          (buffer-substring pos (match-beginning 0))
 410          (xml-parse-string))))
 411      ;;  DTD for the document
 412      ((looking-at "<!DOCTYPE")
 413       (let ((dtd (xml-parse-dtd parse-ns)))
 414         (skip-syntax-forward " ")
 415         (if xml-validating-parser
 416             (cons dtd (xml-parse-tag nil xml-ns))
 417           (xml-parse-tag nil xml-ns))))
 418      ;;  skip comments
 419      ((looking-at "<!--")
 420       (search-forward "-->")
 421       nil)
 422      ;;  end tag
 423      ((looking-at "</")
 424       '())
 425      ;;  opening tag
 426      ((looking-at "<\\([^/>[:space:]]+\\)")
 427       (goto-char (match-end 1))
 428
 429       ;; Parse this node
 430       (let* ((node-name (match-string 1))
 431              ;; Parse the attribute list.
 432              (attrs (xml-parse-attlist xml-ns))
 433              children pos)
 434
 435         ;; add the xmlns:* attrs to our cache
 436         (when (consp xml-ns)
 437           (dolist (attr attrs)
 438             (when (and (consp (car attr))
 439                        (equal "http://www.w3.org/2000/xmlns/"
 440                               (caar attr)))
 441               (push (cons (cdar attr) (cdr attr))
 442                     xml-ns))))
 443
 444         (setq children (list attrs (xml-maybe-do-ns node-name "" xml-ns)))
 445
 446         ;; is this an empty element ?
 447         (if (looking-at "/>")
 448             (progn
 449               (forward-char 2)
 450               (nreverse children))
 451
 452           ;; is this a valid start tag ?
 453           (if (eq (char-after) ?>)
 454               (progn
 455                 (forward-char 1)
 456                 ;;  Now check that we have the right end-tag. Note that this
 457                 ;;  one might contain spaces after the tag name
 458                 (let ((end (concat "</" node-name "\\s-*>")))
 459                   (while (not (looking-at end))
 460                     (cond
 461                      ((looking-at "</")
 462                       (error "XML: (Not Well-Formed) Invalid end tag (expecting %s) at pos %d"
 463                              node-name (point)))
 464                      ((= (char-after) ?<)
 465                       (let ((tag (xml-parse-tag nil xml-ns)))
 466                         (when tag
 467                           (push tag children))))
 468                      (t
 469                       (let ((expansion (xml-parse-string)))
 470                         (setq children
 471                               (if (stringp expansion)
 472                                   (if (stringp (car children))
 473                                       ;; The two strings were separated by a comment.
 474                                       (setq children (append (list (concat (car children) expansion))
 475                                                              (cdr children)))
 476                                     (setq children (append (list expansion) children)))
 477                                 (setq children (append expansion children))))))))
 478
 479                   (goto-char (match-end 0))
 480                   (nreverse children)))
 481             ;;  This was an invalid start tag (Expected ">", but didn't see it.)
 482             (error "XML: (Well-Formed) Couldn't parse tag: %s"
 483                    (buffer-substring (- (point) 10) (+ (point) 1)))))))
 484      (t ;; (Not one of PI, CDATA, Comment, End tag, or Start tag)
 485       (unless xml-sub-parser            ; Usually, we error out.
 486         (error "XML: (Well-Formed) Invalid character"))
 487
 488       ;; However, if we're parsing incrementally, then we need to deal
 489       ;; with stray CDATA.
 490       (xml-parse-string)))))
 491
 492 (defun xml-parse-string ()
 493   "Parse the next whatever.  Could be a string, or an element."
 494   (let* ((pos (point))
 495          (string (progn (if (search-forward "<" nil t)
 496                             (forward-char -1)
 497                           (goto-char (point-max)))
 498                         (buffer-substring pos (point)))))
 499     ;; Clean up the string.  As per XML specifications, the XML
 500     ;; processor should always pass the whole string to the
 501     ;; application.  But \r's should be replaced:
 502     ;; http://www.w3.org/TR/2000/REC-xml-20001006#sec-line-ends
 503     (setq pos 0)
 504     (while (string-match "\r\n?" string pos)
 505       (setq string (replace-match "\n" t t string))
 506       (setq pos (1+ (match-beginning 0))))
 507
 508     (xml-substitute-special string)))
 509
 510 (defun xml-parse-attlist (&optional xml-ns)
 511   "Return the attribute-list after point.
 512 Leave point at the first non-blank character after the tag."
 513   (let ((attlist ())
 514         end-pos name)
 515     (skip-syntax-forward " ")
 516     (while (looking-at (eval-when-compile
 517                          (concat "\\(" xml-name-regexp "\\)\\s-*=\\s-*")))
 518       (setq end-pos (match-end 0))
 519       (setq name (xml-maybe-do-ns (match-string 1) nil xml-ns))
 520       (goto-char end-pos)
 521
 522       ;; See also: http://www.w3.org/TR/2000/REC-xml-20001006#AVNormalize
 523
 524       ;; Do we have a string between quotes (or double-quotes),
 525       ;;  or a simple word ?
 526       (if (looking-at "\"\\([^\"]*\\)\"")
 527           (setq end-pos (match-end 0))
 528         (if (looking-at "'\\([^']*\\)'")
 529             (setq end-pos (match-end 0))
 530           (error "XML: (Not Well-Formed) Attribute values must be given between quotes")))
 531
 532       ;; Each attribute must be unique within a given element
 533       (if (assoc name attlist)
 534           (error "XML: (Not Well-Formed) Each attribute must be unique within an element"))
 535
 536       ;; Multiple whitespace characters should be replaced with a single one
 537       ;; in the attributes
 538       (let ((string (match-string 1))
 539             (pos 0))
 540         (replace-regexp-in-string "\\s-\\{2,\\}" " " string)
 541         (let ((expansion (xml-substitute-special string)))
 542           (unless (stringp expansion)
 543                                         ; We say this is the constraint.  It is acctually that
 544                                         ; external entities nor "<" can be in an attribute value.
 545             (error "XML: (Not Well-Formed) Entities in attributes cannot expand into elements"))
 546           (push (cons name expansion) attlist)))
 547
 548       (goto-char end-pos)
 549       (skip-syntax-forward " "))
 550     (nreverse attlist)))
 551
 552 ;;*******************************************************************
 553 ;;**
 554 ;;**  The DTD (document type declaration)
 555 ;;**  The following functions know how to skip or parse the DTD of
 556 ;;**  a document
 557 ;;**
 558 ;;*******************************************************************
 559
 560 ;; Fixme: This fails at least if the DTD contains conditional sections.
 561
 562 (defun xml-skip-dtd ()
 563   "Skip the DTD at point.
 564 This follows the rule [28] in the XML specifications."
 565   (let ((xml-validating-parser nil))
 566     (xml-parse-dtd)))
 567
 568 (defun xml-parse-dtd (&optional parse-ns)
 569   "Parse the DTD at point."
 570   (forward-char (eval-when-compile (length "<!DOCTYPE")))
 571   (skip-syntax-forward " ")
 572   (if (and (looking-at ">")
 573            xml-validating-parser)
 574       (error "XML: (Validity) Invalid DTD (expecting name of the document)"))
 575
 576   ;;  Get the name of the document
 577   (looking-at xml-name-regexp)
 578   (let ((dtd (list (match-string 0) 'dtd))
 579         type element end-pos)
 580     (goto-char (match-end 0))
 581
 582     (skip-syntax-forward " ")
 583     ;; XML [75]
 584     (cond ((looking-at "PUBLIC\\s-+")
 585            (goto-char (match-end 0))
 586            (unless (or (re-search-forward
 587                         "\\=\"\\([[:space:][:alnum:]-'()+,./:=?;!*#@$_%]*\\)\""
 588                         nil t)
 589                        (re-search-forward
 590                         "\\='\\([[:space:][:alnum:]-()+,./:=?;!*#@$_%]*\\)'"
 591                         nil t))
 592              (error "XML: Missing Public ID"))
 593            (let ((pubid (match-string 1)))
 594              (skip-syntax-forward " ")
 595              (unless (or (re-search-forward "\\='\\([^']*\\)'" nil t)
 596                          (re-search-forward "\\=\"\\([^\"]*\\)\"" nil t))
 597                (error "XML: Missing System ID"))
 598              (push (list pubid (match-string 1) 'public) dtd)))
 599           ((looking-at "SYSTEM\\s-+")
 600            (goto-char (match-end 0))
 601            (unless (or (re-search-forward "\\='\\([^']*\\)'" nil t)
 602                        (re-search-forward "\\=\"\\([^\"]*\\)\"" nil t))
 603              (error "XML: Missing System ID"))
 604            (push (list (match-string 1) 'system) dtd)))
 605     (skip-syntax-forward " ")
 606     (if (eq ?> (char-after))
 607         (forward-char)
 608       (if (not (eq (char-after) ?\[))
 609           (error "XML: Bad DTD")
 610         (forward-char)
 611         ;;  Parse the rest of the DTD
 612         ;;  Fixme: Deal with NOTATION, PIs.
 613         (while (not (looking-at "\\s-*\\]"))
 614           (skip-syntax-forward " ")
 615           (cond
 616
 617            ;;  Translation of rule [45] of XML specifications
 618            ((looking-at
 619              "<!ELEMENT\\s-+\\([[:alnum:].%;]+\\)\\s-+\\([^>]+\\)>")
 620
 621             (setq element (match-string 1)
 622                   type    (match-string-no-properties 2))
 623             (setq end-pos (match-end 0))
 624
 625             ;;  Translation of rule [46] of XML specifications
 626             (cond
 627              ((string-match "^EMPTY[ \t\n\r]*$" type) ;; empty declaration
 628               (setq type 'empty))
 629              ((string-match "^ANY[ \t\n\r]*$" type) ;; any type of contents
 630               (setq type 'any))
 631              ((string-match "^(\\(.*\\))[ \t\n\r]*$" type) ;; children ([47])
 632               (setq type (xml-parse-elem-type (match-string 1 type))))
 633              ((string-match "^%[^;]+;[ \t\n\r]*$" type) ;; substitution
 634               nil)
 635              (t
 636               (if xml-validating-parser
 637                   (error "XML: (Validity) Invalid element type in the DTD"))))
 638
 639             ;;  rule [45]: the element declaration must be unique
 640             (if (and (assoc element dtd)
 641                      xml-validating-parser)
 642                 (error "XML: (Validity) Element declarations must be unique in a DTD (<%s>)"
 643                        element))
 644
 645             ;;  Store the element in the DTD
 646             (push (list element type) dtd)
 647             (goto-char end-pos))
 648
 649            ;; Translation of rule [52] of XML specifications
 650            ((looking-at (concat "<!ATTLIST[ \t\n\r]*\\(" xml-name-re
 651                                 "\\)[ \t\n\r]*\\(" xml-att-def-re
 652                                 "\\)*[ \t\n\r]*>"))
 653
 654             ;; We don't do anything with ATTLIST currently
 655             (goto-char (match-end 0)))
 656
 657            ((looking-at "<!--")
 658             (search-forward "-->"))
 659            ((looking-at (concat "<!ENTITY[ \t\n\r]*\\(" xml-name-re
 660                                 "\\)[ \t\n\r]*\\(" xml-entity-value-re
 661                                 "\\)[ \t\n\r]*>"))
 662             (let ((name  (match-string 1))
 663                   (value (substring (match-string 2) 1
 664                                     (- (length (match-string 2)) 1))))
 665               (goto-char (match-end 0))
 666               (setq xml-entity-alist
 667                     (append xml-entity-alist
 668                             (list (cons name
 669                                         (with-temp-buffer
 670                                           (insert value)
 671                                           (goto-char (point-min))
 672                                           (xml-parse-fragment
 673                                            xml-validating-parser
 674                                            parse-ns))))))))
 675            ((or (looking-at (concat "<!ENTITY[ \t\n\r]+\\(" xml-name-re
 676                                     "\\)[ \t\n\r]+SYSTEM[ \t\n\r]+"
 677                                     "\\(\"[^\"]*\"\\|'[^']*'\\)[ \t\n\r]*>"))
 678                 (looking-at (concat "<!ENTITY[ \t\n\r]+\\(" xml-name-re
 679                                     "\\)[ \t\n\r]+PUBLIC[ \t\n\r]+"
 680                                     "\"[- \r\na-zA-Z0-9'()+,./:=?;!*#@$_%]*\""
 681                                     "\\|'[- \r\na-zA-Z0-9()+,./:=?;!*#@$_%]*'"
 682                                     "[ \t\n\r]+\\(\"[^\"]*\"\\|'[^']*'\\)"
 683                                     "[ \t\n\r]*>")))
 684             (let ((name  (match-string 1))
 685                   (file  (substring (match-string 2) 1
 686                                     (- (length (match-string 2)) 1))))
 687               (goto-char (match-end 0))
 688               (setq xml-entity-alist
 689                     (append xml-entity-alist
 690                             (list (cons name (with-temp-buffer
 691                                                (insert-file-contents file)
 692                                                (goto-char (point-min))
 693                                                (xml-parse-fragment
 694                                                 xml-validating-parser
 695                                                 parse-ns))))))))
 696            ;; skip parameter entity declarations
 697            ((or (looking-at (concat "<!ENTITY[ \t\n\r]+%[ \t\n\r]+\\(" xml-name-re
 698                                     "\\)[ \t\n\r]+SYSTEM[ \t\n\r]+"
 699                                     "\\(\"[^\"]*\"\\|'[^']*'\\)[ \t\n\r]*>"))
 700                 (looking-at (concat "<!ENTITY[ \t\n\r]+"
 701                                     "%[ \t\n\r]+"
 702                                     "\\(" xml-name-re "\\)[ \t\n\r]+"
 703                                     "PUBLIC[ \t\n\r]+"
 704                                     "\\(\"[- \r\na-zA-Z0-9'()+,./:=?;!*#@$_%]*\""
 705                                     "\\|'[- \r\na-zA-Z0-9()+,./:=?;!*#@$_%]*'\\)[ \t\n\r]+"
 706                                     "\\(\"[^\"]+\"\\|'[^']+'\\)"
 707                                     "[ \t\n\r]*>")))
 708             (goto-char (match-end 0)))
 709            ;; skip parameter entities
 710            ((looking-at (concat "%" xml-name-re ";"))
 711             (goto-char (match-end 0)))
 712            (t
 713             (when xml-validating-parser
 714               (error "XML: (Validity) Invalid DTD item"))))))
 715       (if (looking-at "\\s-*]>")
 716           (goto-char (match-end 0))))
 717     (nreverse dtd)))
 718
 719 (defun xml-parse-elem-type (string)
 720   "Convert element type STRING into a Lisp structure."
 721
 722   (let (elem modifier)
 723     (if (string-match "(\\([^)]+\\))\\([+*?]?\\)" string)
 724         (progn
 725           (setq elem     (match-string 1 string)
 726                 modifier (match-string 2 string))
 727           (if (string-match "|" elem)
 728               (setq elem (cons 'choice
 729                                (mapcar 'xml-parse-elem-type
 730                                        (split-string elem "|"))))
 731             (if (string-match "," elem)
 732                 (setq elem (cons 'seq
 733                                  (mapcar 'xml-parse-elem-type
 734                                          (split-string elem ",")))))))
 735       (if (string-match "[ \t\n\r]*\\([^+*?]+\\)\\([+*?]?\\)" string)
 736           (setq elem     (match-string 1 string)
 737                 modifier (match-string 2 string))))
 738
 739     (if (and (stringp elem) (string= elem "#PCDATA"))
 740         (setq elem 'pcdata))
 741
 742     (cond
 743      ((string= modifier "+")
 744       (list '+ elem))
 745      ((string= modifier "*")
 746       (list '* elem))
 747      ((string= modifier "?")
 748       (list '\? elem))
 749      (t
 750       elem))))
 751
 752 ;;*******************************************************************
 753 ;;**
 754 ;;**  Substituting special XML sequences
 755 ;;**
 756 ;;*******************************************************************
 757
 758 (defun xml-substitute-special (string)
 759   "Return STRING, after subsituting entity references."
 760   ;; This originally made repeated passes through the string from the
 761   ;; beginning, which isn't correct, since then either "&amp;amp;" or
 762   ;; "&#38;amp;" won't DTRT.
 763
 764   (let ((point 0)
 765         children end-point)
 766     (while (string-match "&\\([^;]*\\);" string point)
 767       (setq end-point (match-end 0))
 768       (let* ((this-part (match-string 1 string))
 769              (prev-part (substring string point (match-beginning 0)))
 770              (entity (assoc this-part xml-entity-alist))
 771              (expansion
 772               (cond ((string-match "#\\([0-9]+\\)" this-part)
 773                      (let ((c (decode-char
 774                                'ucs
 775                                (string-to-number (match-string 1 this-part)))))
 776                        (if c (string c))))
 777                     ((string-match "#x\\([[:xdigit:]]+\\)" this-part)
 778                      (let ((c (decode-char
 779                                'ucs
 780                                (string-to-number (match-string 1 this-part) 16))))
 781                        (if c (string c))))
 782                     (entity
 783                      (cdr entity))
 784                     ((eq (length this-part) 0)
 785                      (error "XML: (Not Well-Formed) No entity given"))
 786                     (t
 787                      (if xml-validating-parser
 788                          (error "XML: (Validity) Undefined entity `%s'"
 789                                 this-part)
 790                        xml-undefined-entity)))))
 791
 792         (cond ((null children)
 793                ;; FIXME: If we have an entity that expands into XML, this won't work.
 794                (setq children
 795                      (concat prev-part expansion)))
 796               ((stringp children)
 797                (if (stringp expansion)
 798                    (setq children (concat children prev-part expansion))
 799                  (setq children (list expansion (concat prev-part children)))))
 800               ((and (stringp expansion)
 801                     (stringp (car children)))
 802                (setcar children (concat prev-part expansion (car children))))
 803               ((stringp expansion)
 804                (setq children (append (concat prev-part expansion)
 805                                       children)))
 806               ((stringp (car children))
 807                (setcar children (concat (car children) prev-part))
 808                (setq children (append expansion children)))
 809               (t
 810                (setq children (list expansion
 811                                     prev-part
 812                                     children))))
 813         (setq point end-point)))
 814     (cond ((stringp children)
 815            (concat children (substring string point)))
 816           ((stringp (car (last children)))
 817            (concat (car (last children)) (substring string point)))
 818           ((null children)
 819            string)
 820           (t
 821            (concat (mapconcat 'identity
 822                               (nreverse children)
 823                               "")
 824                    (substring string point))))))
 825
 826 ;;*******************************************************************
 827 ;;**
 828 ;;**  Printing a tree.
 829 ;;**  This function is intended mainly for debugging purposes.
 830 ;;**
 831 ;;*******************************************************************
 832
 833 (defun xml-debug-print (xml &optional indent-string)
 834   "Outputs the XML in the current buffer.
 835 XML can be a tree or a list of nodes.
 836 The first line is indented with the optional INDENT-STRING."
 837   (setq indent-string (or indent-string ""))
 838   (dolist (node xml)
 839     (xml-debug-print-internal node indent-string)))
 840
 841 (defalias 'xml-print 'xml-debug-print)
 842
 843 (defun xml-debug-print-internal (xml indent-string)
 844   "Outputs the XML tree in the current buffer.
 845 The first line is indented with INDENT-STRING."
 846   (let ((tree xml)
 847         attlist)
 848     (insert indent-string ?< (symbol-name (xml-node-name tree)))
 849
 850     ;;  output the attribute list
 851     (setq attlist (xml-node-attributes tree))
 852     (while attlist
 853       (insert ?\  (symbol-name (caar attlist)) "=\"" (cdar attlist) ?\")
 854       (setq attlist (cdr attlist)))
 855
 856     (setq tree (xml-node-children tree))
 857
 858     (if (null tree)
 859         (insert ?/ ?>)
 860       (insert ?>)
 861
 862       ;;  output the children
 863       (dolist (node tree)
 864         (cond
 865          ((listp node)
 866           (insert ?\n)
 867           (xml-debug-print-internal node (concat indent-string "  ")))
 868          ((stringp node) (insert node))
 869          (t
 870           (error "Invalid XML tree"))))
 871
 872       (when (not (and (null (cdr tree))
 873                       (stringp (car tree))))
 874         (insert ?\n indent-string))
 875       (insert ?< ?/ (symbol-name (xml-node-name xml)) ?>))))
 876
 877 (provide 'xml)
 878
 879 ;; arch-tag: 5864b283-5a68-4b59-a20d-36a72b353b9b
 880 ;;; xml.el ends here