Re: [Exist-open] xpath descendant bug

[Michael B. <mbe...@mb...>]

Bryan Rasmussen wrote:


> Hi the following xpath returns nothing
>
> /xs:schema[descendant::xs:complexType[@name]]
>

Bug! Simple test
==========
let $doc :=
<top>
        <section>
         <div2 xml:id="d1">
             <p>In div with id d1</p>
       </div2>
      <div2>
             <p>In div with no id</p>
     </div2>
      </section>
        <section>
         <div2>
             <p>In div with no id</p>
       </div2>
     <div2>
             <p>In div with no id</p>
    </div2>
      </section>
</top>

return $doc//section[descendant::div2[@xml:id]]

================================

In eXist this returns nothing, in Saxon it correctly returns

<?xml version="1.0" encoding="UTF-8"?>
<section>
   <div2 xml:id="d1">
      <p>In div with id d1</p>
   </div2>
   <div2>
      <p>In div with no id</p>
   </div2>
</section>
========================================

> I suppose the reason is that the descendant axis only applies to element
> content, but it seems to me that the attribute name is not on the
> descendant axis by xpath rules.

Don't forget that you can change axis at each and every step in an XPath,
and within a predicate expression. So just because you start off down the
descendant axis doesn't mean you can't turn to look along the attribute axis
of whatever node(s) are selected at a given step. Saxon does just that and
sees what it ought to. eXist apparently sees nothing, though it certainly
should.

Michael Beddow