File size: 14,188 Bytes
3dcad1f |
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 |
;;;; (sxml simple) -- a simple interface to the SSAX parser
;;;;
;;;; Copyright (C) 2009, 2010, 2013 Free Software Foundation, Inc.
;;;; Modified 2004 by Andy Wingo <wingo at pobox dot com>.
;;;; Originally written by Oleg Kiselyov <oleg at pobox dot com> as SXML-to-HTML.scm.
;;;;
;;;; This library is free software; you can redistribute it and/or
;;;; modify it under the terms of the GNU Lesser General Public
;;;; License as published by the Free Software Foundation; either
;;;; version 3 of the License, or (at your option) any later version.
;;;;
;;;; This library 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
;;;; Lesser General Public License for more details.
;;;;
;;;; You should have received a copy of the GNU Lesser General Public
;;;; License along with this library; if not, write to the Free Software
;;;; Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
;;;;
;;; Commentary:
;;
;;A simple interface to XML parsing and serialization.
;;
;;; Code:
(define-module (sxml simple)
#:use-module (sxml ssax input-parse)
#:use-module (sxml ssax)
#:use-module (sxml transform)
#:use-module (ice-9 match)
#:export (xml->sxml sxml->xml sxml->string))
;; Helpers from upstream/SSAX.scm.
;;
; ssax:reverse-collect-str LIST-OF-FRAGS -> LIST-OF-FRAGS
; given the list of fragments (some of which are text strings)
; reverse the list and concatenate adjacent text strings.
; We can prove from the general case below that if LIST-OF-FRAGS
; has zero or one element, the result of the procedure is equal?
; to its argument. This fact justifies the shortcut evaluation below.
(define (ssax:reverse-collect-str fragments)
(cond
((null? fragments) '()) ; a shortcut
((null? (cdr fragments)) fragments) ; see the comment above
(else
(let loop ((fragments fragments) (result '()) (strs '()))
(cond
((null? fragments)
(if (null? strs) result
(cons (string-concatenate/shared strs) result)))
((string? (car fragments))
(loop (cdr fragments) result (cons (car fragments) strs)))
(else
(loop (cdr fragments)
(cons
(car fragments)
(if (null? strs) result
(cons (string-concatenate/shared strs) result)))
'())))))))
(define (read-internal-doctype-as-string port)
(string-concatenate/shared
(let loop ()
(let ((fragment
(next-token '() '(#\]) "reading internal DOCTYPE" port)))
(if (eqv? #\> (peek-next-char port))
(begin
(read-char port)
(cons fragment '()))
(cons* fragment "]" (loop)))))))
;; Ideas for the future for this interface:
;;
;; * Allow doctypes to provide parsed entities
;;
;; * Allow validation (the ELEMENTS value from the DOCTYPE handler
;; below)
;;
;; * Parse internal DTDs
;;
;; * Parse external DTDs
;;
(define* (xml->sxml #:optional (string-or-port (current-input-port)) #:key
(namespaces '())
(declare-namespaces? #t)
(trim-whitespace? #f)
(entities '())
(default-entity-handler #f)
(doctype-handler #f))
"Use SSAX to parse an XML document into SXML. Takes one optional
argument, @var{string-or-port}, which defaults to the current input
port."
;; NAMESPACES: alist of PREFIX -> URI. Specifies the symbol prefix
;; that the user wants on elements of a given namespace in the
;; resulting SXML, regardless of the abbreviated namespaces defined in
;; the document by xmlns attributes. If DECLARE-NAMESPACES? is true,
;; these namespaces are treated as if they were declared in the DTD.
;; ENTITIES: alist of SYMBOL -> STRING.
;; NAMESPACES: list of (DOC-PREFIX . (USER-PREFIX . URI)).
;; A DOC-PREFIX of #f indicates that it comes from the user.
;; Otherwise, prefixes are symbols.
(define (munge-namespaces namespaces)
(map (lambda (el)
(match el
((prefix . uri-string)
(cons* (and declare-namespaces? prefix)
prefix
(ssax:uri-string->symbol uri-string)))))
namespaces))
(define (user-namespaces)
(munge-namespaces namespaces))
(define (user-entities)
(if (and default-entity-handler
(not (assq '*DEFAULT* entities)))
(acons '*DEFAULT* default-entity-handler entities)
entities))
(define (name->sxml name)
(match name
((prefix . local-part)
(symbol-append prefix (string->symbol ":") local-part))
(_ name)))
(define (doctype-continuation seed)
(lambda* (#:key (entities '()) (namespaces '()))
(values #f
(append entities (user-entities))
(append (munge-namespaces namespaces) (user-namespaces))
seed)))
;; The SEED in this parser is the SXML: initialized to '() at each new
;; level by the fdown handlers; built in reverse by the fhere parsers;
;; and reverse-collected by the fup handlers.
(define parser
(ssax:make-parser
NEW-LEVEL-SEED ; fdown
(lambda (elem-gi attributes namespaces expected-content seed)
'())
FINISH-ELEMENT ; fup
(lambda (elem-gi attributes namespaces parent-seed seed)
(let ((seed (if trim-whitespace?
(ssax:reverse-collect-str-drop-ws seed)
(ssax:reverse-collect-str seed)))
(attrs (attlist-fold
(lambda (attr accum)
(cons (list (name->sxml (car attr)) (cdr attr))
accum))
'() attributes)))
(acons (name->sxml elem-gi)
(if (null? attrs)
seed
(cons (cons '@ attrs) seed))
parent-seed)))
CHAR-DATA-HANDLER ; fhere
(lambda (string1 string2 seed)
(if (string-null? string2)
(cons string1 seed)
(cons* string2 string1 seed)))
DOCTYPE
;; -> ELEMS ENTITIES NAMESPACES SEED
;;
;; ELEMS is for validation and currently unused.
;;
;; ENTITIES is an alist of parsed entities (symbol -> string).
;;
;; NAMESPACES is as above.
;;
;; SEED builds up the content.
(lambda (port docname systemid internal-subset? seed)
(call-with-values
(lambda ()
(cond
(doctype-handler
(doctype-handler docname systemid
(and internal-subset?
(read-internal-doctype-as-string port))))
(else
(when internal-subset?
(ssax:skip-internal-dtd port))
(values))))
(doctype-continuation seed)))
UNDECL-ROOT
;; This is like the DOCTYPE handler, but for documents that do not
;; have a <!DOCTYPE!> entry.
(lambda (elem-gi seed)
(call-with-values
(lambda ()
(if doctype-handler
(doctype-handler #f #f #f)
(values)))
(doctype-continuation seed)))
PI
((*DEFAULT*
. (lambda (port pi-tag seed)
(cons
(list '*PI* pi-tag (ssax:read-pi-body-as-string port))
seed))))))
(let* ((port (if (string? string-or-port)
(open-input-string string-or-port)
string-or-port))
(elements (reverse (parser port '()))))
`(*TOP* ,@elements)))
(define check-name
(let ((*good-cache* (make-hash-table)))
(lambda (name)
(if (not (hashq-ref *good-cache* name))
(let* ((str (symbol->string name))
(i (string-index str #\:))
(head (or (and i (substring str 0 i)) str))
(tail (and i (substring str (1+ i)))))
(and i (string-index (substring str (1+ i)) #\:)
(error "Invalid QName: more than one colon" name))
(for-each
(lambda (s)
(and s
(or (char-alphabetic? (string-ref s 0))
(eq? (string-ref s 0) #\_)
(error "Invalid name starting character" s name))
(string-for-each
(lambda (c)
(or (char-alphabetic? c) (string-index "0123456789.-_" c)
(error "Invalid name character" c s name)))
s)))
(list head tail))
(hashq-set! *good-cache* name #t))))))
;; The following two functions serialize tags and attributes. They are
;; being used in the node handlers for the post-order function, see
;; below.
(define (attribute-value->xml value port)
(cond
((pair? value)
(attribute-value->xml (car value) port)
(attribute-value->xml (cdr value) port))
((null? value)
*unspecified*)
((string? value)
(string->escaped-xml value port))
((procedure? value)
(with-output-to-port port value))
(else
(string->escaped-xml
(call-with-output-string (lambda (port) (display value port)))
port))))
(define (attribute->xml attr value port)
(check-name attr)
(display attr port)
(display "=\"" port)
(attribute-value->xml value port)
(display #\" port))
(define (element->xml tag attrs body port)
(check-name tag)
(display #\< port)
(display tag port)
(if attrs
(let lp ((attrs attrs))
(if (pair? attrs)
(let ((attr (car attrs)))
(display #\space port)
(if (pair? attr)
(attribute->xml (car attr) (cdr attr) port)
(error "bad attribute" tag attr))
(lp (cdr attrs)))
(if (not (null? attrs))
(error "bad attributes" tag attrs)))))
(if (pair? body)
(begin
(display #\> port)
(let lp ((body body))
(cond
((pair? body)
(sxml->xml (car body) port)
(lp (cdr body)))
((null? body)
(display "</" port)
(display tag port)
(display ">" port))
(else
(error "bad element body" tag body)))))
(display " />" port)))
;; FIXME: ensure name is valid
(define (entity->xml name port)
(display #\& port)
(display name port)
(display #\; port))
;; FIXME: ensure tag and str are valid
(define (pi->xml tag str port)
(display "<?" port)
(display tag port)
(display #\space port)
(display str port)
(display "?>" port))
(define* (sxml->xml tree #:optional (port (current-output-port)))
"Serialize the sxml tree @var{tree} as XML. The output will be written
to the current output port, unless the optional argument @var{port} is
present."
(cond
((pair? tree)
(if (symbol? (car tree))
;; An element.
(let ((tag (car tree)))
(case tag
((*TOP*)
(sxml->xml (cdr tree) port))
((*ENTITY*)
(if (and (list? (cdr tree)) (= (length (cdr tree)) 1))
(entity->xml (cadr tree) port)
(error "bad *ENTITY* args" (cdr tree))))
((*PI*)
(if (and (list? (cdr tree)) (= (length (cdr tree)) 2))
(pi->xml (cadr tree) (caddr tree) port)
(error "bad *PI* args" (cdr tree))))
(else
(let* ((elems (cdr tree))
(attrs (and (pair? elems) (pair? (car elems))
(eq? '@ (caar elems))
(cdar elems))))
(element->xml tag attrs (if attrs (cdr elems) elems) port)))))
;; A nodelist.
(for-each (lambda (x) (sxml->xml x port)) tree)))
((string? tree)
(string->escaped-xml tree port))
((null? tree) *unspecified*)
((not tree) *unspecified*)
((eqv? tree #t) *unspecified*)
((procedure? tree)
(with-output-to-port port tree))
(else
(string->escaped-xml
(call-with-output-string (lambda (port) (display tree port)))
port))))
(define (sxml->string sxml)
"Detag an sxml tree @var{sxml} into a string. Does not perform any
formatting."
(string-concatenate-reverse
(foldts
(lambda (seed tree) ; fdown
'())
(lambda (seed kid-seed tree) ; fup
(append! kid-seed seed))
(lambda (seed tree) ; fhere
(if (string? tree) (cons tree seed) seed))
'()
sxml)))
(define (make-char-quotator char-encoding)
(let ((bad-chars (list->char-set (map car char-encoding))))
;; Check to see if str contains one of the characters in charset,
;; from the position i onward. If so, return that character's index.
;; otherwise, return #f
(define (index-cset str i charset)
(string-index str charset i))
;; The body of the function
(lambda (str port)
(let ((bad-pos (index-cset str 0 bad-chars)))
(if (not bad-pos)
(display str port) ; str had all good chars
(let loop ((from 0) (to bad-pos))
(cond
((>= from (string-length str)) *unspecified*)
((not to)
(display (substring str from (string-length str)) port))
(else
(let ((quoted-char
(cdr (assv (string-ref str to) char-encoding)))
(new-to
(index-cset str (+ 1 to) bad-chars)))
(if (< from to)
(display (substring str from to) port))
(display quoted-char port)
(loop (1+ to) new-to))))))))))
;; Given a string, check to make sure it does not contain characters
;; such as '<' or '&' that require encoding. Return either the original
;; string, or a list of string fragments with special characters
;; replaced by appropriate character entities.
(define string->escaped-xml
(make-char-quotator
'((#\< . "<") (#\> . ">") (#\& . "&") (#\" . """))))
;;; arch-tag: 9c853b25-d82f-42ef-a959-ae26fdc7d1ac
;;; simple.scm ends here
|