The W3C XML Schema Working Group has published a list of strong concerns regarding the XInclude Last Call Working Draft and its lack of harmonization with the "other foundation specifications."

Mary Holstege, for the W3C XML Schema Working Group, has posted a list of inconsistencies between XInclude and other W3C and IETF specifications (including W3C XML Schema):

We believe that the XInclude specification defines a foundation specification that has to be harmonized carefully with the other foundation specifications.

The list includes the following points:

1. XInclude should "be crystal clear which Infoset properties are adjusted, and how, and further that it should specify rules so that core invariants are maintained" especially with properties mentioned as needing specific processing in the Last Call WD such as namespaces, base, notations and entities and PSVI properties.
2. The overall processing model is undefined and "it is not possible to know whether XInclude will be applied before or after validation" impacting the ability to write schemas for documents using XInclude.
3. XInclude shouldn't "erase all record that XInclude processing has occurred".
4. XInclude should follow the IETF specifications for fragment identifiers or give a better justification for violating them.
5. The W3C XML Schema included in the XInclude specification "does not quite capture the expressed constraints".
6. The W3C XML Schema WG is "doubtful whether it is appropriate to mandate normalized characters in all circumstances".

The first three points show the difficulty of progressing foundation specifications as independent pieces of work, and the case of type aware XPath/XInclude is an interesting puzzle.

Other stories:

• XML Inclusions enters Last Call
• Berners-Lee announces W3C XML Schema Recommendation