[xml] Xpath and default attribute value

[Jean Senellart <senellart systran fr>]

Hi,

I have a probably trivial question about XPath and test on default value - but I do not see where is my 
misunderstanding. I have following xml with embedded dtd - just note the default value "0" for attribute "st".

--------
<?xml version="1.0" encoding="iso-8859-1"?>
<!DOCTYPE test_unit [
<!ELEMENT test_unit EMPTY>
<!ATTLIST test_unit st  (ok|failed|disabled|skipped|0)     "0">
]>
<test_unit/>
--------
It seemed to me that I should find "/test_unit[ st=0]" but it does not*

What I found in specification, which seems related to this point is 
(http://www.w3.org/TR/xpath#attribute-nodes):
> NOTE: It is possible for default attributes to be declared in an external DTD or an external parameter 
> entity. The XML Recommendation does not require an XML processor to read an external DTD or an external 
> parameter unless it is validating. A stylesheet or other facility that assumes that the XPath tree contains 
> default attribute values declared in an external DTD or parameter entity may not work with some 
> non-validating XML processors

my reformulation of this is: with a validating XML processor, we could assume the tree contains default 
attribute value and therefore should not "/test_unit[ st=0]" match in my example?

thank you for any answer on this point

Jean

*here is the test:

  xmlDoValidityCheckingDefaultValue=1;
  xmlInitParser();
  xmlParserCtxtPtr ctxt = xmlCreateFileParserCtxt(argv[1]);
  if (ctxt == NULL) {
    return(0);
  }
  xmlParseDocument(ctxt);
  xmlDocPtr Doc=ctxt->myDoc;
  if (!ctxt->valid) {
    fprintf(stderr,"document not valid\n");
    exit(0);
  }
  xmlXPathContextPtr ctx=xmlXPathNewContext(Doc);
  
  // check that the "st" attribute gets its value from dtd
  fprintf(stderr,"value of 'st' attribute:%s\n",xmlGetProp(xmlDocGetRootElement(Doc),(const xmlChar*)"st"));


  xmlXPathObjectPtr optval1=xmlXPathEval((const xmlChar*)"//test_unit[ st=0]",ctx);
  if (!xmlXPathCastToBoolean (optval1)) {
    fprintf(stderr,"match on //test_unit[ st=0] failed\n");
  } 

  xmlXPathObjectPtr optval2=xmlXPathEval((const xmlChar*)"//test_unit",ctx);
  if (!xmlXPathCastToBoolean (optval2)) {
    fprintf(stderr,"match on //test_unit[ st=0] failed\n");
}