XPath and Multiple Namespaces

I'm having nightmares with xpath queries on xml documents with multiple
namespaces.  For example, take the following test file:

<test xmlns="http://main.com" xmlns:sub="http://sub.com">
  <item>
    <subitem>
      <sub:testnode>Testing 1 2 3</sub:testnode>
    </subitem>
  </item>
</test>

You'd expect that I could access the testnode using:
/i:test/i:item/i:subitem/sub:testnode

Where i is a reference to the default namespace specified using
xpath_register_ns() as was suggested in a post on one of the news groups.

But it seems that xpath_register_ns() overwrites previously specified
namespaces, for example:

1  $xpath = $dom->xpath_new_context();
2  xpath_register_ns($xpath,"sub", "http://sub.com");
3  xpath_register_ns($xpath,"i", "http://main.com");
4  $xnode = xpath_eval($xpath,"/i:test");
5  print_r($xnode);

Will find the root node, however swap lines 2 and 3 around and it will fail.
So my problem seems to stem from registering multiple name spaces.

Hope this makes sense and someone can help.

Regards

Dan

---------------------------------------------
       act : making e-learning work
---------------------------------------------

  Daniel Pupius BSc(hons) MA
  Senior Lead Developer
  email: [email protected]

  New Oxford House
  30 Barker's Pool
  Sheffield S1 2HB
  Tel: 0114 278 0798
  Fax: 0114 249 1773

---------------------------------------------
       http://www.actelearning.com/
---------------------------------------------