Commit | Line | Data |
---|---|---|
47db06aa GM |
1 | ;; @(#) xml.el --- XML parser |
2 | ||
3 | ;; Copyright (C) 2000 Free Software Foundation, Inc. | |
4 | ||
5 | ;; Author: Emmanuel Briot <briot@gnat.com> | |
6 | ;; Maintainer: Emmanuel Briot <briot@gnat.com> | |
7 | ;; Keywords: xml | |
8 | ||
9 | ;; This file is part of GNU Emacs. | |
10 | ||
11 | ;; GNU Emacs is free software; you can redistribute it and/or modify | |
12 | ;; it under the terms of the GNU General Public License as published by | |
13 | ;; the Free Software Foundation; either version 2, or (at your option) | |
14 | ;; any later version. | |
15 | ||
16 | ;; GNU Emacs is distributed in the hope that it will be useful, | |
17 | ;; but WITHOUT ANY WARRANTY; without even the implied warranty of | |
18 | ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
19 | ;; GNU General Public License for more details. | |
20 | ||
21 | ;; You should have received a copy of the GNU General Public License | |
22 | ;; along with GNU Emacs; see the file COPYING. If not, write to the | |
23 | ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330, | |
24 | ;; Boston, MA 02111-1307, USA. | |
25 | ||
26 | ;;; Commentary: | |
27 | ||
28 | ;; This file contains a full XML parser. It parses a file, and returns a list | |
29 | ;; that can be used internally by any other lisp file. | |
30 | ;; See some example in todo.el | |
31 | ||
32 | ;;; FILE FORMAT | |
33 | ||
34 | ;; It does not parse the DTD, if present in the XML file, but knows how to | |
35 | ;; ignore it. The XML file is assumed to be well-formed. In case of error, the | |
36 | ;; parsing stops and the XML file is shown where the parsing stopped. | |
37 | ;; | |
38 | ;; It also knows how to ignore comments, as well as the special ?xml? tag | |
39 | ;; in the XML file. | |
40 | ;; | |
41 | ;; The XML file should have the following format: | |
42 | ;; <node1 attr1="name1" attr2="name2" ...> value | |
43 | ;; <node2 attr3="name3" attr4="name4"> value2 </node2> | |
44 | ;; <node3 attr5="name5" attr6="name6"> value3 </node3> | |
45 | ;; </node1> | |
46 | ;; Of course, the name of the nodes and attributes can be anything. There can | |
47 | ;; be any number of attributes (or none), as well as any number of children | |
48 | ;; below the nodes. | |
49 | ;; | |
50 | ;; There can be only top level node, but with any number of children below. | |
51 | ||
52 | ;;; LIST FORMAT | |
53 | ||
54 | ;; The functions `xml-parse-file' and `xml-parse-tag' return a list with | |
55 | ;; the following format: | |
56 | ;; | |
57 | ;; xml-list ::= (node node ...) | |
58 | ;; node ::= (tag_name attribute-list . child_node_list) | |
59 | ;; child_node_list ::= child_node child_node ... | |
60 | ;; child_node ::= node | string | |
61 | ;; tag_name ::= string | |
62 | ;; attribute_list ::= (("attribute" . "value") ("attribute" . "value") ...) | |
63 | ;; | nil | |
64 | ;; string ::= "..." | |
65 | ;; | |
66 | ;; Since XML is case insensitive, tag_name is always converted to lower-cases. | |
67 | ;; tag_name is then converted to a symbol (this is not a string, so that the | |
68 | ;; list takes less space in memory and is faster to traverse). | |
69 | ;; | |
70 | ;; Some macros are provided to ease the parsing of this list | |
71 | ||
72 | ;;; Code: | |
73 | ||
74 | ;;******************************************************************* | |
75 | ;;** | |
76 | ;;** Macros to parse the list | |
77 | ;;** | |
78 | ;;******************************************************************* | |
79 | ||
80 | (defmacro xml-node-name (node) | |
81 | "Return the tag associated with NODE. | |
82 | The tag is a lower-case symbol." | |
83 | (list 'car node)) | |
84 | ||
85 | (defmacro xml-node-attributes (node) | |
86 | "Return the list of attributes of NODE. | |
87 | The list can be nil." | |
88 | (list 'nth 1 node)) | |
89 | ||
90 | (defmacro xml-node-children (node) | |
91 | "Return the list of children of NODE. | |
92 | This is a list of nodes, and it can be nil." | |
93 | (list 'cddr node)) | |
94 | ||
95 | (defun xml-get-children (node child-name) | |
96 | "Return the children of NODE whose tag is CHILD-NAME. | |
97 | CHILD-NAME should be a lower case symbol." | |
98 | (let ((children (xml-node-children node)) | |
99 | match) | |
100 | (while children | |
101 | (if (car children) | |
102 | (if (equal (xml-node-name (car children)) child-name) | |
103 | (set 'match (append match (list (car children)))))) | |
104 | (set 'children (cdr children))) | |
105 | match)) | |
106 | ||
107 | (defun xml-get-attribute (node attribute) | |
108 | "Get from NODE the value of ATTRIBUTE. | |
109 | An empty string is returned if the attribute was not found." | |
110 | (if (xml-node-attributes node) | |
111 | (let ((value (assoc attribute (xml-node-attributes node)))) | |
112 | (if value | |
113 | (cdr value) | |
114 | "")) | |
115 | "")) | |
116 | ||
117 | ;;******************************************************************* | |
118 | ;;** | |
119 | ;;** Creating the list | |
120 | ;;** | |
121 | ;;******************************************************************* | |
122 | ||
123 | (defun xml-parse-file (file &optional parse-dtd) | |
124 | "Parse the well-formed XML FILE. | |
125 | Returns the top node with all its children. | |
126 | If PARSE-DTD is non-nil, the DTD is parsed rather than skipped." | |
127 | (find-file file) | |
128 | (let ((xml (xml-parse-region (point-min) | |
129 | (point-max) | |
130 | (current-buffer) | |
131 | parse-dtd))) | |
132 | (kill-buffer (current-buffer)) | |
133 | xml)) | |
134 | ||
135 | (defun xml-parse-region (beg end &optional buffer parse-dtd) | |
136 | "Parse the region from BEG to END in BUFFER. | |
137 | If BUFFER is nil, it defaults to the current buffer. | |
138 | Returns the XML list for the region, or raises an error if the region | |
139 | is not a well-formed XML file. | |
140 | If PARSE-DTD is non-nil, the DTD is parsed rather than skipped, | |
141 | and returned as the first element of the list" | |
142 | (let (xml result dtd) | |
143 | (save-excursion | |
144 | (if buffer | |
145 | (set-buffer buffer)) | |
146 | (goto-char beg) | |
147 | (while (< (point) end) | |
148 | (if (search-forward "<" end t) | |
149 | (progn | |
150 | (forward-char -1) | |
151 | (if (null xml) | |
152 | (progn | |
153 | (set 'result (xml-parse-tag end parse-dtd)) | |
154 | (cond | |
155 | ((listp (car result)) | |
156 | (set 'dtd (car result)) | |
157 | (add-to-list 'xml (cdr result))) | |
158 | (t | |
159 | (add-to-list 'xml result)))) | |
160 | ||
161 | ;; translation of rule [1] of XML specifications | |
162 | (error "XML files can have only one toplevel tag."))) | |
163 | (goto-char end))) | |
164 | (if parse-dtd | |
165 | (cons dtd (reverse xml)) | |
166 | (reverse xml))))) | |
167 | ||
168 | ||
169 | (defun xml-parse-tag (end &optional parse-dtd) | |
170 | "Parse the tag that is just in front of point. | |
171 | The end tag must be found before the position END in the current buffer. | |
172 | If PARSE-DTD is non-nil, the DTD of the document, if any, is parsed and | |
173 | returned as the first element in the list. | |
174 | Returns one of: | |
175 | - a list : the matching node | |
176 | - nil : the point is not looking at a tag. | |
177 | - a cons cell: the first element is the DTD, the second is the node" | |
178 | (cond | |
179 | ;; Processing instructions (like the <?xml version="1.0"?> tag at the | |
180 | ;; beginning of a document) | |
181 | ((looking-at "<\\?") | |
182 | (search-forward "?>" end) | |
183 | (skip-chars-forward " \t\n") | |
184 | (xml-parse-tag end)) | |
185 | ;; Character data (CDATA) sections, in which no tag should be interpreted | |
186 | ((looking-at "<!\\[CDATA\\[") | |
187 | (let ((pos (match-end 0))) | |
188 | (unless (search-forward "]]>" end t) | |
189 | (error "CDATA section does not end anywhere in the document")) | |
190 | (buffer-substring-no-properties pos (match-beginning 0)))) | |
191 | ;; DTD for the document | |
192 | ((looking-at "<!DOCTYPE") | |
193 | (let (dtd) | |
194 | (if parse-dtd | |
195 | (set 'dtd (xml-parse-dtd end)) | |
196 | (xml-skip-dtd end)) | |
197 | (skip-chars-forward " \t\n") | |
198 | (if dtd | |
199 | (cons dtd (xml-parse-tag end)) | |
200 | (xml-parse-tag end)))) | |
201 | ;; skip comments | |
202 | ((looking-at "<!--") | |
203 | (search-forward "-->" end) | |
204 | (skip-chars-forward " \t\n") | |
205 | (xml-parse-tag end)) | |
206 | ;; end tag | |
207 | ((looking-at "</") | |
208 | '()) | |
209 | ;; opening tag | |
210 | ((looking-at "<\\([^/> \t]+\\)") | |
211 | (let* ((node-name (match-string 1)) | |
212 | (children (list (intern (downcase node-name)))) | |
213 | pos) | |
214 | (goto-char (match-end 1)) | |
215 | ||
216 | ;; parses the attribute list | |
217 | (set 'children (append children (list (xml-parse-attlist end)))) | |
218 | ||
219 | ;; is this an empty element ? | |
220 | (if (looking-at "/>") | |
221 | (progn | |
222 | (forward-char 2) | |
223 | (skip-chars-forward " \t\n") | |
224 | (append children '(""))) | |
225 | ||
226 | ;; is this a valid start tag ? | |
227 | (if (= (char-after) ?>) | |
228 | (progn | |
229 | (forward-char 1) | |
230 | (skip-chars-forward " \t\n") | |
231 | (while (not (looking-at (concat "</" node-name ">"))) | |
232 | (cond | |
233 | ((looking-at "</") | |
234 | (error (concat | |
235 | "XML: invalid syntax -- invalid end tag (expecting " | |
236 | node-name | |
237 | ")"))) | |
238 | ((= (char-after) ?<) | |
239 | (set 'children (append children (list (xml-parse-tag end))))) | |
240 | (t | |
241 | (set 'pos (point)) | |
242 | (search-forward "<" end) | |
243 | (forward-char -1) | |
244 | (let ((string (buffer-substring-no-properties pos (point))) | |
245 | (pos 0)) | |
246 | ||
247 | ;; Clean up the string (no newline characters) | |
248 | ;; Not done, since as per XML specifications, the XML processor | |
249 | ;; should always pass the whole string to the application. | |
250 | ;; (while (string-match "\\s +" string pos) | |
251 | ;; (set 'string (replace-match " " t t string)) | |
252 | ;; (set 'pos (1+ (match-beginning 0)))) | |
253 | ||
254 | (set 'children (append children | |
255 | (list (xml-substitute-special string)))))))) | |
256 | (goto-char (match-end 0)) | |
257 | (skip-chars-forward " \t\n") | |
258 | (if (> (point) end) | |
259 | (error "XML: End tag for %s not found before end of region." | |
260 | node-name)) | |
261 | children | |
262 | ) | |
263 | ||
264 | ;; This was an invalid start tag | |
265 | (error "XML: Invalid attribute list") | |
266 | )))) | |
267 | )) | |
268 | ||
269 | (defun xml-parse-attlist (end) | |
270 | "Return the attribute-list that point is looking at. | |
271 | The search for attributes end at the position END in the current buffer. | |
272 | Leaves the point on the first non-blank character after the tag." | |
273 | (let ((attlist '()) | |
274 | name) | |
275 | (skip-chars-forward " \t\n") | |
276 | (while (looking-at "\\([a-zA-Z_:][a-zA-Z0-9.-_:]*\\)[ \t\n]*=[ \t\n]*") | |
277 | (set 'name (intern (downcase (match-string 1)))) | |
278 | (goto-char (match-end 0)) | |
279 | ||
280 | ;; Do we have a string between quotes (or double-quotes), | |
281 | ;; or a simple word ? | |
282 | (unless (looking-at "\"\\([^\"]+\\)\"") | |
283 | (unless (looking-at "'\\([^\"]+\\)'") | |
284 | (error "XML: Attribute values must be given between quotes."))) | |
285 | ||
286 | ;; Each attribute must be unique within a given element | |
287 | (if (assoc name attlist) | |
288 | (error "XML: each attribute must be unique within an element.")) | |
289 | ||
290 | (set 'attlist (append attlist | |
291 | (list (cons name (match-string 1))))) | |
292 | (goto-char (match-end 0)) | |
293 | (skip-chars-forward " \t\n") | |
294 | (if (> (point) end) | |
295 | (error "XML: end of attribute list not found before end of region.")) | |
296 | ) | |
297 | attlist | |
298 | )) | |
299 | ||
300 | ;;******************************************************************* | |
301 | ;;** | |
302 | ;;** The DTD (document type declaration) | |
303 | ;;** The following functions know how to skip or parse the DTD of | |
304 | ;;** a document | |
305 | ;;** | |
306 | ;;******************************************************************* | |
307 | ||
308 | (defun xml-skip-dtd (end) | |
309 | "Skip the DTD that point is looking at. | |
310 | The DTD must end before the position END in the current buffer. | |
311 | The point must be just before the starting tag of the DTD. | |
312 | This follows the rule [28] in the XML specifications." | |
313 | (forward-char (length "<!DOCTYPE")) | |
314 | (if (looking-at "[ \t\n]*>") | |
315 | (error "XML: invalid DTD (excepting name of the document)")) | |
316 | (condition-case nil | |
317 | (progn | |
318 | (forward-word 1) ;; name of the document | |
319 | (skip-chars-forward " \t\n") | |
320 | (if (looking-at "\\[") | |
321 | (re-search-forward "\\][ \t\n]*>" end) | |
322 | (search-forward ">" end))) | |
323 | (error (error "XML: No end to the DTD")))) | |
324 | ||
325 | (defun xml-parse-dtd (end) | |
326 | "Parse the DTD that point is looking at. | |
327 | The DTD must end before the position END in the current buffer." | |
328 | (let (dtd type element end-pos) | |
329 | (forward-char (length "<!DOCTYPE")) | |
330 | (skip-chars-forward " \t\n") | |
331 | (if (looking-at ">") | |
332 | (error "XML: invalid DTD (excepting name of the document)")) | |
333 | ||
334 | ;; Get the name of the document | |
335 | (looking-at "\\sw+") | |
336 | (set 'dtd (list 'dtd (match-string-no-properties 0))) | |
337 | (goto-char (match-end 0)) | |
338 | ||
339 | (skip-chars-forward " \t\n") | |
340 | ||
341 | ;; External DTDs => don't know how to handle them yet | |
342 | (if (looking-at "SYSTEM") | |
343 | (error "XML: Don't know how to handle external DTDs.")) | |
344 | ||
345 | (if (not (= (char-after) ?\[)) | |
346 | (error "XML: Unknown declaration in the DTD.")) | |
347 | ||
348 | ;; Parse the rest of the DTD | |
349 | (forward-char 1) | |
350 | (while (and (not (looking-at "[ \t\n]*\\]")) | |
351 | (<= (point) end)) | |
352 | (cond | |
353 | ||
354 | ;; Translation of rule [45] of XML specifications | |
355 | ((looking-at | |
356 | "[\t \n]*<!ELEMENT[ \t\n]+\\([a-zA-Z0-9.%;]+\\)[ \t\n]+\\([^>]+\\)>") | |
357 | ||
358 | (setq element (intern (downcase (match-string-no-properties 1))) | |
359 | type (match-string-no-properties 2)) | |
360 | (set 'end-pos (match-end 0)) | |
361 | ||
362 | ;; Translation of rule [46] of XML specifications | |
363 | (cond | |
364 | ((string-match "^EMPTY[ \t\n]*$" type) ;; empty declaration | |
365 | (set 'type 'empty)) | |
366 | ((string-match "^ANY[ \t\n]*$" type) ;; any type of contents | |
367 | (set 'type 'any)) | |
368 | ((string-match "^(\\(.*\\))[ \t\n]*$" type) ;; children ([47]) | |
369 | (set 'type (xml-parse-elem-type (match-string-no-properties 1 type)))) | |
370 | ((string-match "^%[^;]+;[ \t\n]*$" type) ;; substitution | |
371 | nil) | |
372 | (t | |
373 | (error "XML: Invalid element type in the DTD"))) | |
374 | ||
375 | ;; rule [45]: the element declaration must be unique | |
376 | (if (assoc element dtd) | |
377 | (error "XML: elements declaration must be unique in a DTD (<%s>)." | |
378 | (symbol-name element))) | |
379 | ||
380 | ;; Store the element in the DTD | |
381 | (set 'dtd (append dtd (list (list element type)))) | |
382 | (goto-char end-pos) | |
383 | ) | |
384 | ||
385 | ||
386 | (t | |
387 | (error "XML: Invalid DTD item")) | |
388 | ) | |
389 | ) | |
390 | ||
391 | ;; Skip the end of the DTD | |
392 | (search-forward ">" end) | |
393 | dtd | |
394 | )) | |
395 | ||
396 | ||
397 | (defun xml-parse-elem-type (string) | |
398 | "Convert a STRING for an element type into an elisp structure." | |
399 | ||
400 | (let (elem modifier) | |
401 | (if (string-match "(\\([^)]+\\))\\([+*?]?\\)" string) | |
402 | (progn | |
403 | (setq elem (match-string 1 string) | |
404 | modifier (match-string 2 string)) | |
405 | (if (string-match "|" elem) | |
406 | (set 'elem (append '(choice) | |
407 | (mapcar 'xml-parse-elem-type | |
408 | (split-string elem "|")))) | |
409 | (if (string-match "," elem) | |
410 | (set 'elem (append '(seq) | |
411 | (mapcar 'xml-parse-elem-type | |
412 | (split-string elem ",")))) | |
413 | ))) | |
414 | (if (string-match "[ \t\n]*\\([^+*?]+\\)\\([+*?]?\\)" string) | |
415 | (setq elem (match-string 1 string) | |
416 | modifier (match-string 2 string)))) | |
417 | ||
418 | (if (and (stringp elem) | |
419 | (string= elem "#PCDATA")) | |
420 | (set 'elem 'pcdata)) | |
421 | ||
422 | (cond | |
423 | ((string= modifier "+") | |
424 | (list '+ elem)) | |
425 | ((string= modifier "*") | |
426 | (list '* elem)) | |
427 | ((string= modifier "?") | |
428 | (list '? elem)) | |
429 | (t | |
430 | elem)))) | |
431 | ||
432 | ||
433 | ;;******************************************************************* | |
434 | ;;** | |
435 | ;;** Substituting special XML sequences | |
436 | ;;** | |
437 | ;;******************************************************************* | |
438 | ||
439 | (defun xml-substitute-special (string) | |
440 | "Return STRING, after subsituting special XML sequences." | |
441 | (while (string-match "&" string) | |
442 | (set 'string (replace-match "&" t nil string))) | |
443 | (while (string-match "<" string) | |
444 | (set 'string (replace-match "<" t nil string))) | |
445 | (while (string-match ">" string) | |
446 | (set 'string (replace-match ">" t nil string))) | |
447 | (while (string-match "'" string) | |
448 | (set 'string (replace-match "'" t nil string))) | |
449 | (while (string-match """ string) | |
450 | (set 'string (replace-match "\"" t nil string))) | |
451 | string) | |
452 | ||
453 | ;;******************************************************************* | |
454 | ;;** | |
455 | ;;** Printing a tree. | |
456 | ;;** This function is intended mainly for debugging purposes. | |
457 | ;;** | |
458 | ;;******************************************************************* | |
459 | ||
460 | (defun xml-debug-print (xml) | |
461 | (while xml | |
462 | (xml-debug-print-internal (car xml) "") | |
463 | (set 'xml (cdr xml))) | |
464 | ) | |
465 | ||
466 | (defun xml-debug-print-internal (xml &optional indent-string) | |
467 | "Outputs the XML tree in the current buffer. | |
468 | The first line indented with INDENT-STRING." | |
469 | (let ((tree xml) | |
470 | attlist) | |
471 | (unless indent-string | |
472 | (set 'indent-string "")) | |
473 | ||
474 | (insert indent-string "<" (symbol-name (xml-node-name tree))) | |
475 | ||
476 | ;; output the attribute list | |
477 | (set 'attlist (xml-node-attributes tree)) | |
478 | (while attlist | |
479 | (insert " ") | |
480 | (insert (symbol-name (caar attlist)) "=\"" (cdar attlist) "\"") | |
481 | (set 'attlist (cdr attlist))) | |
482 | ||
483 | (insert ">") | |
484 | ||
485 | (set 'tree (xml-node-children tree)) | |
486 | ||
487 | ;; output the children | |
488 | (while tree | |
489 | (cond | |
490 | ((listp (car tree)) | |
491 | (insert "\n") | |
492 | (xml-debug-print-internal (car tree) (concat indent-string " ")) | |
493 | ) | |
494 | ((stringp (car tree)) | |
495 | (insert (car tree)) | |
496 | ) | |
497 | (t | |
498 | (error "Invalid XML tree"))) | |
499 | (set 'tree (cdr tree)) | |
500 | ) | |
501 | ||
502 | (insert "\n" indent-string | |
503 | "</" (symbol-name (xml-node-name xml)) ">") | |
504 | )) | |
505 | ||
506 | (provide 'xml) | |
507 | ||
508 | ;;; xml.el ends here |