RE: [XQuery] 2.6.3 Full Axis Feature

The WG considered your feedback and questions and I am replying on
behalf of the WG.

> What is the rationale for the full axis feature?

The WG originally decided to make this an optional feature in XQuery 1.0
since we could not get consensus on adding the axes as a mandatory
feature in XQuery 1.0. One of the major problems with these axes is that
they are very hard to use with static typing because their type
inference rules lose all type information.  In addition at you noted
parent() and root() can be hard to implement in streaming
implementations.

In addition some WG members said there were implementation difficulties
with these axes and that the use of these axes impacted their ability to
create optimized implementations.  These WG members wanted the
flexibility of producing an XQuery implementation without being force to
implement these axes.

> I would strongly urge that this feature be dropped and that support
for
> the axes be mandatory.

The WG has reconsidered the optionality of the axes for XQuery 1.0 and
even considered the possibility of moving the parent and root axes
(along with the .. and leading / syntax) to the optional feature.

The WG decided to stay with the status quo since this was the position
that received the strongest support.

We would be grateful if you could confirm that this response resolves
the questions you raised in your comment.

/paulc

Paul Cotton, Microsoft Canada 
17 Eleanor Drive, Nepean, Ontario K2E 6A3 
Tel: (613) 225-5445 Fax: (425) 936-7329 
mailto:pcotton@microsoft.com

Received on Tuesday, 20 January 2004 18:06:01 UTC