[liblouis-liblouisxml] Re: Bert, what could cause an XPath expression to return an empty node set?
- From: Bert Frees <bert.frees@xxxxxxxxxxxxxxxx>
- To: liblouis-liblouisxml@xxxxxxxxxxxxx
- Date: Wed, 13 Jan 2010 12:20:13 +0100
I added this peace of code for testing:
xpathexpression = ("//p"); // this is a legal xpath expression
xpathObj = xmlXPathEvalExpression (xpathexpression, xpathCtx);
if(xmlXPathNodeSetIsEmpty(xpathObj->nodesetval)){
printf("Node set is empty\n");
return NULL;
}
I also have to conclude the same: xmlXPathEvalExpression always returns
an object with a empty node list, whatever xpathexpression is used. I
have no clue why :(. The code looks ok to me. Are you sure xpathCtx
points to the right context?
On 12/01/2010 17:58, Bert Frees wrote:
I'm not an xpath expert either, but i'll take a look at the code
tomorrow.
Bert
On 12/01/2010 17:20, John J. Boyer wrote:
Thanks for your patience in testing this feature. Perhaps you can give
me
some clues as to why an xpath expression might be evaluated without
errors but return an empty node set, though the document contains nodes
to which it should apply. After parsing the document I set up an xpath
context, Then look through a table for xpath expressions. If one is
found, it is evaluated with the context to produce an xpath object. The
object is then examined for whatever nodes it may contain and freed. The
scan of the table continues. When it is done the context is also freed.
The code is in do_xpath_expr in the semantics.c module.
Thanks,
John
For a description of the software and to download it go to
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For a description of the software and to download it go to
http://www.jjb-software.com
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