Re: [xml] XPath question w/ libxml2

[Daniel Veillard <veillard redhat com>]

On Thu, Apr 15, 2004 at 05:07:40PM -0600, Mark_Vakoc peoplesoft com wrote:
> > So I agree it sounds like this should select no node.
> > The difference though is that at least on my platform this works as
> > expected:
>   
> Yep, not on my platform (win32):
> C:\gsstools\bin>xmllint --shell c:\t.xml
> / > ls
> ---        9 root
> / > xpath root[1]
> Object is a Node Set :
> Set contains 1 nodes:
> 1  ELEMENT root
> / > xpath root[number('NaN')]
> Object is a Node Set :
> Set contains 1 nodes:
> 1  ELEMENT root
> / >
>
> > I'm afraid you might be seeing some weird floating point troubles.
> > Can you try to see if the basic tests from test/XPath/expr/floats
> > work correctly first ? Then it might be number('NaN') failing or
> > the index tests.
>
> Ok, will look into those tests and try and patch it up now that I know
> what the correct behavior should be.

  The fist thing would be to check the NaN initialization in xpath.c
and taht number('NaN') actually produce the value.
  Gut feeling is that there a int number compared to a NaN double 
in the XPath Predicate evaluation which might set an error flag but
not generate a test error. Hopefully a short session with a debugger
should be able to pinpoint the problem,

  good hunting !

Daniel

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