Namespace normalizer

This XSLT 2.0 stylesheet performs an identity transform on the input, except that namespace declarations are rewritten such that they all appear on the document element (at the top), while preserving the expanded names of all elements and attributes throughout the document.

For example:

BEFORE:

<foo xmlns="default1">
  <abc:bar xmlns="default2andfoo" xmlns:abc="default1">
    <bat xmlns:foo="default2andfoo" foo:bar="value">
      <bang xmlns="default3">
        <abc:hi xmlns:xyz="unused-uri"/>
      </bang>
    </bat>
  </abc:bar>
</foo>

AFTER:

<foo xmlns="default1" xmlns:foo="default2andfoo" xmlns:ns1="default3" xmlns:xyz="unused-uri">
  <bar>
    <foo:bat foo:bar="value">
      <ns1:bang>
        <hi/>
      </ns1:bang>
    </foo:bat>
  </bar>
</foo>

For more background and detailed considerations on this, as well as an XSLT 1.0 version of this script, see Namespace normalizer.