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47f3ce52 AW |
1 | ;;;; (sxml simple) -- a simple interface to the SSAX parser |
2 | ;;;; | |
1488753a | 3 | ;;;; Copyright (C) 2009, 2010, 2013 Free Software Foundation, Inc. |
47f3ce52 AW |
4 | ;;;; Modified 2004 by Andy Wingo <wingo at pobox dot com>. |
5 | ;;;; Originally written by Oleg Kiselyov <oleg at pobox dot com> as SXML-to-HTML.scm. | |
6 | ;;;; | |
7 | ;;;; This library is free software; you can redistribute it and/or | |
8 | ;;;; modify it under the terms of the GNU Lesser General Public | |
9 | ;;;; License as published by the Free Software Foundation; either | |
10 | ;;;; version 3 of the License, or (at your option) any later version. | |
11 | ;;;; | |
12 | ;;;; This library is distributed in the hope that it will be useful, | |
13 | ;;;; but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | ;;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
15 | ;;;; Lesser General Public License for more details. | |
16 | ;;;; | |
17 | ;;;; You should have received a copy of the GNU Lesser General Public | |
18 | ;;;; License along with this library; if not, write to the Free Software | |
19 | ;;;; Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
20 | ;;;; | |
21 | \f | |
22 | ;;; Commentary: | |
23 | ;; | |
24 | ;;A simple interface to XML parsing and serialization. | |
25 | ;; | |
26 | ;;; Code: | |
27 | ||
28 | (define-module (sxml simple) | |
29 | #:use-module (sxml ssax) | |
30 | #:use-module (sxml transform) | |
1488753a | 31 | #:use-module (ice-9 match) |
47f3ce52 | 32 | #:use-module (srfi srfi-13) |
d9fff48e | 33 | #:export (xml->sxml sxml->xml sxml->string)) |
47f3ce52 | 34 | |
1488753a AW |
35 | ;; Helpers from upstream/SSAX.scm. |
36 | ;; | |
37 | ||
38 | (define (ssax:warn port msg . args) | |
39 | (format (current-ssax-error-port) | |
40 | ";;; SSAX warning: ~a ~a\n" msg args)) | |
41 | ||
42 | ; ssax:reverse-collect-str LIST-OF-FRAGS -> LIST-OF-FRAGS | |
43 | ; given the list of fragments (some of which are text strings) | |
44 | ; reverse the list and concatenate adjacent text strings. | |
45 | ; We can prove from the general case below that if LIST-OF-FRAGS | |
46 | ; has zero or one element, the result of the procedure is equal? | |
47 | ; to its argument. This fact justifies the shortcut evaluation below. | |
48 | (define (ssax:reverse-collect-str fragments) | |
49 | (cond | |
50 | ((null? fragments) '()) ; a shortcut | |
51 | ((null? (cdr fragments)) fragments) ; see the comment above | |
52 | (else | |
53 | (let loop ((fragments fragments) (result '()) (strs '())) | |
54 | (cond | |
55 | ((null? fragments) | |
56 | (if (null? strs) result | |
57 | (cons (string-concatenate/shared strs) result))) | |
58 | ((string? (car fragments)) | |
59 | (loop (cdr fragments) result (cons (car fragments) strs))) | |
60 | (else | |
61 | (loop (cdr fragments) | |
62 | (cons | |
63 | (car fragments) | |
64 | (if (null? strs) result | |
65 | (cons (string-concatenate/shared strs) result))) | |
66 | '()))))))) | |
67 | ||
68 | ;; Ideas for the future for this interface: | |
69 | ;; | |
70 | ;; * Allow doctypes to provide parsed entities | |
71 | ;; | |
72 | ;; * Allow validation (the ELEMENTS value from the DOCTYPE handler | |
73 | ;; below) | |
74 | ;; | |
75 | ;; * Parse internal DTDs | |
76 | ;; | |
77 | ;; * Parse external DTDs | |
78 | ;; | |
79 | (define* (xml->sxml #:optional (port (current-input-port)) #:key | |
80 | (namespaces '()) | |
81 | (declare-namespaces? #t) | |
82 | (trim-whitespace? #f) | |
83 | (entities '()) | |
84 | (default-entity-handler #f)) | |
47f3ce52 AW |
85 | "Use SSAX to parse an XML document into SXML. Takes one optional |
86 | argument, @var{port}, which defaults to the current input port." | |
1488753a AW |
87 | ;; NAMESPACES: alist of PREFIX -> URI. Specifies the symbol prefix |
88 | ;; that the user wants on elements of a given namespace in the | |
89 | ;; resulting SXML, regardless of the abbreviated namespaces defined in | |
90 | ;; the document by xmlns attributes. If DECLARE-NAMESPACES? is true, | |
91 | ;; these namespaces are treated as if they were declared in the DTD. | |
92 | ||
93 | ;; ENTITIES: alist of SYMBOL -> STRING. | |
94 | ||
95 | ;; NAMESPACES: list of (DOC-PREFIX . (USER-PREFIX . URI)). | |
96 | ;; A DOC-PREFIX of #f indicates that it comes from the user. | |
97 | ;; Otherwise, prefixes are symbols. | |
98 | (define (user-namespaces) | |
99 | (map (lambda (el) | |
100 | (match el | |
101 | ((prefix . uri-string) | |
102 | (cons* (and declare-namespaces? prefix) | |
103 | prefix | |
104 | (ssax:uri-string->symbol uri-string))))) | |
105 | namespaces)) | |
106 | ||
107 | (define (user-entities) | |
108 | (if (and default-entity-handler | |
109 | (not (assq '*DEFAULT* entities))) | |
110 | (acons '*DEFAULT* default-entity-handler entities) | |
111 | entities)) | |
112 | ||
113 | (define (name->sxml name) | |
114 | (match name | |
115 | ((prefix . local-part) | |
116 | (symbol-append prefix (string->symbol ":") local-part)) | |
117 | (_ name))) | |
118 | ||
119 | ;; The SEED in this parser is the SXML: initialized to '() at each new | |
120 | ;; level by the fdown handlers; built in reverse by the fhere parsers; | |
121 | ;; and reverse-collected by the fup handlers. | |
122 | (define parser | |
123 | (ssax:make-parser | |
124 | NEW-LEVEL-SEED ; fdown | |
125 | (lambda (elem-gi attributes namespaces expected-content seed) | |
126 | '()) | |
127 | ||
128 | FINISH-ELEMENT ; fup | |
129 | (lambda (elem-gi attributes namespaces parent-seed seed) | |
130 | (let ((seed (if trim-whitespace? | |
131 | (ssax:reverse-collect-str-drop-ws seed) | |
132 | (ssax:reverse-collect-str seed))) | |
133 | (attrs (attlist-fold | |
134 | (lambda (attr accum) | |
135 | (cons (list (name->sxml (car attr)) (cdr attr)) | |
136 | accum)) | |
137 | '() attributes))) | |
138 | (acons (name->sxml elem-gi) | |
139 | (if (null? attrs) | |
140 | seed | |
141 | (cons (cons '@ attrs) seed)) | |
142 | parent-seed))) | |
143 | ||
144 | CHAR-DATA-HANDLER ; fhere | |
145 | (lambda (string1 string2 seed) | |
146 | (if (string-null? string2) | |
147 | (cons string1 seed) | |
148 | (cons* string2 string1 seed))) | |
149 | ||
150 | DOCTYPE | |
151 | ;; -> ELEMS ENTITIES NAMESPACES SEED | |
152 | ;; | |
153 | ;; ELEMS is for validation and currently unused. | |
154 | ;; | |
155 | ;; ENTITIES is an alist of parsed entities (symbol -> string). | |
156 | ;; | |
157 | ;; NAMESPACES is as above. | |
158 | ;; | |
159 | ;; SEED builds up the content. | |
160 | (lambda (port docname systemid internal-subset? seed) | |
161 | (when internal-subset? | |
162 | (ssax:warn port "Internal DTD subset is not currently handled ") | |
163 | (ssax:skip-internal-dtd port)) | |
164 | (ssax:warn port "DOCTYPE DECL " docname " " | |
165 | systemid " found and skipped") | |
166 | (values #f (user-entities) (user-namespaces) seed)) | |
167 | ||
168 | UNDECL-ROOT | |
169 | ;; This is like the DOCTYPE handler, but for documents that do not | |
170 | ;; have a <!DOCTYPE!> entry. | |
171 | (lambda (elem-gi seed) | |
172 | (values #f (user-entities) (user-namespaces) seed)) | |
173 | ||
174 | PI | |
175 | ((*DEFAULT* | |
176 | . (lambda (port pi-tag seed) | |
177 | (cons | |
178 | (list '*PI* pi-tag (ssax:read-pi-body-as-string port)) | |
179 | seed)))))) | |
180 | ||
181 | `(*TOP* ,@(reverse (parser port '())))) | |
47f3ce52 | 182 | |
d9fff48e AW |
183 | (define check-name |
184 | (let ((*good-cache* (make-hash-table))) | |
185 | (lambda (name) | |
186 | (if (not (hashq-ref *good-cache* name)) | |
187 | (let* ((str (symbol->string name)) | |
188 | (i (string-index str #\:)) | |
189 | (head (or (and i (substring str 0 i)) str)) | |
190 | (tail (and i (substring str (1+ i))))) | |
191 | (and i (string-index (substring str (1+ i)) #\:) | |
192 | (error "Invalid QName: more than one colon" name)) | |
193 | (for-each | |
194 | (lambda (s) | |
195 | (and s | |
196 | (or (char-alphabetic? (string-ref s 0)) | |
197 | (eq? (string-ref s 0) #\_) | |
198 | (error "Invalid name starting character" s name)) | |
199 | (string-for-each | |
200 | (lambda (c) | |
201 | (or (char-alphabetic? c) (string-index "0123456789.-_" c) | |
202 | (error "Invalid name character" c s name))) | |
203 | s))) | |
204 | (list head tail)) | |
205 | (hashq-set! *good-cache* name #t)))))) | |
206 | ||
207 | ;; The following two functions serialize tags and attributes. They are | |
208 | ;; being used in the node handlers for the post-order function, see | |
209 | ;; below. | |
210 | ||
211 | (define (attribute-value->xml value port) | |
212 | (cond | |
213 | ((pair? value) | |
214 | (attribute-value->xml (car value) port) | |
215 | (attribute-value->xml (cdr value) port)) | |
6901bad0 AW |
216 | ((null? value) |
217 | *unspecified*) | |
d9fff48e AW |
218 | ((string? value) |
219 | (string->escaped-xml value port)) | |
220 | ((procedure? value) | |
221 | (with-output-to-port port value)) | |
222 | (else | |
223 | (string->escaped-xml | |
224 | (call-with-output-string (lambda (port) (display value port))) | |
225 | port)))) | |
226 | ||
227 | (define (attribute->xml attr value port) | |
228 | (check-name attr) | |
229 | (display attr port) | |
230 | (display "=\"" port) | |
231 | (attribute-value->xml value port) | |
232 | (display #\" port)) | |
233 | ||
234 | (define (element->xml tag attrs body port) | |
235 | (check-name tag) | |
236 | (display #\< port) | |
237 | (display tag port) | |
238 | (if attrs | |
239 | (let lp ((attrs attrs)) | |
240 | (if (pair? attrs) | |
241 | (let ((attr (car attrs))) | |
242 | (display #\space port) | |
243 | (if (pair? attr) | |
244 | (attribute->xml (car attr) (cdr attr) port) | |
245 | (error "bad attribute" tag attr)) | |
246 | (lp (cdr attrs))) | |
247 | (if (not (null? attrs)) | |
248 | (error "bad attributes" tag attrs))))) | |
249 | (if (pair? body) | |
250 | (begin | |
251 | (display #\> port) | |
252 | (let lp ((body body)) | |
253 | (cond | |
254 | ((pair? body) | |
255 | (sxml->xml (car body) port) | |
256 | (lp (cdr body))) | |
257 | ((null? body) | |
258 | (display "</" port) | |
259 | (display tag port) | |
260 | (display ">" port)) | |
261 | (else | |
262 | (error "bad element body" tag body))))) | |
263 | (display " />" port))) | |
264 | ||
265 | ;; FIXME: ensure name is valid | |
266 | (define (entity->xml name port) | |
267 | (display #\& port) | |
268 | (display name port) | |
269 | (display #\; port)) | |
270 | ||
271 | ;; FIXME: ensure tag and str are valid | |
272 | (define (pi->xml tag str port) | |
273 | (display "<?" port) | |
274 | (display tag port) | |
275 | (display #\space port) | |
276 | (display str port) | |
277 | (display "?>" port)) | |
47f3ce52 AW |
278 | |
279 | (define* (sxml->xml tree #:optional (port (current-output-port))) | |
280 | "Serialize the sxml tree @var{tree} as XML. The output will be written | |
281 | to the current output port, unless the optional argument @var{port} is | |
282 | present." | |
d9fff48e AW |
283 | (cond |
284 | ((pair? tree) | |
285 | (if (symbol? (car tree)) | |
286 | ;; An element. | |
287 | (let ((tag (car tree))) | |
288 | (case tag | |
289 | ((*TOP*) | |
290 | (sxml->xml (cdr tree) port)) | |
291 | ((*ENTITY*) | |
292 | (if (and (list? (cdr tree)) (= (length (cdr tree)) 1)) | |
293 | (entity->xml (cadr tree) port) | |
294 | (error "bad *ENTITY* args" (cdr tree)))) | |
295 | ((*PI*) | |
296 | (if (and (list? (cdr tree)) (= (length (cdr tree)) 2)) | |
297 | (pi->xml (cadr tree) (caddr tree) port) | |
298 | (error "bad *PI* args" (cdr tree)))) | |
299 | (else | |
300 | (let* ((elems (cdr tree)) | |
301 | (attrs (and (pair? elems) (pair? (car elems)) | |
302 | (eq? '@ (caar elems)) | |
303 | (cdar elems)))) | |
304 | (element->xml tag attrs (if attrs (cdr elems) elems) port))))) | |
305 | ;; A nodelist. | |
306 | (for-each (lambda (x) (sxml->xml x port)) tree))) | |
307 | ((string? tree) | |
308 | (string->escaped-xml tree port)) | |
309 | ((null? tree) *unspecified*) | |
310 | ((not tree) *unspecified*) | |
311 | ((eqv? tree #t) *unspecified*) | |
312 | ((procedure? tree) | |
313 | (with-output-to-port port tree)) | |
314 | (else | |
315 | (string->escaped-xml | |
316 | (call-with-output-string (lambda (port) (display tree port))) | |
317 | port)))) | |
47f3ce52 AW |
318 | |
319 | (define (sxml->string sxml) | |
320 | "Detag an sxml tree @var{sxml} into a string. Does not perform any | |
321 | formatting." | |
322 | (string-concatenate-reverse | |
323 | (foldts | |
324 | (lambda (seed tree) ; fdown | |
325 | '()) | |
326 | (lambda (seed kid-seed tree) ; fup | |
327 | (append! kid-seed seed)) | |
328 | (lambda (seed tree) ; fhere | |
329 | (if (string? tree) (cons tree seed) seed)) | |
330 | '() | |
331 | sxml))) | |
332 | ||
47f3ce52 | 333 | (define (make-char-quotator char-encoding) |
d9fff48e | 334 | (let ((bad-chars (list->char-set (map car char-encoding)))) |
47f3ce52 AW |
335 | |
336 | ;; Check to see if str contains one of the characters in charset, | |
337 | ;; from the position i onward. If so, return that character's index. | |
338 | ;; otherwise, return #f | |
339 | (define (index-cset str i charset) | |
d9fff48e AW |
340 | (string-index str charset i)) |
341 | ||
47f3ce52 | 342 | ;; The body of the function |
d9fff48e | 343 | (lambda (str port) |
47f3ce52 | 344 | (let ((bad-pos (index-cset str 0 bad-chars))) |
d9fff48e AW |
345 | (if (not bad-pos) |
346 | (display str port) ; str had all good chars | |
347 | (let loop ((from 0) (to bad-pos)) | |
348 | (cond | |
349 | ((>= from (string-length str)) *unspecified*) | |
350 | ((not to) | |
351 | (display (substring str from (string-length str)) port)) | |
352 | (else | |
353 | (let ((quoted-char | |
354 | (cdr (assv (string-ref str to) char-encoding))) | |
355 | (new-to | |
356 | (index-cset str (+ 1 to) bad-chars))) | |
357 | (if (< from to) | |
358 | (display (substring str from to) port)) | |
359 | (display quoted-char port) | |
360 | (loop (1+ to) new-to)))))))))) | |
47f3ce52 AW |
361 | |
362 | ;; Given a string, check to make sure it does not contain characters | |
363 | ;; such as '<' or '&' that require encoding. Return either the original | |
364 | ;; string, or a list of string fragments with special characters | |
365 | ;; replaced by appropriate character entities. | |
366 | ||
367 | (define string->escaped-xml | |
368 | (make-char-quotator | |
369 | '((#\< . "<") (#\> . ">") (#\& . "&") (#\" . """)))) | |
370 | ||
371 | ;;; arch-tag: 9c853b25-d82f-42ef-a959-ae26fdc7d1ac | |
372 | ;;; simple.scm ends here | |
373 |