RE: aggregate , grouping

[Martin Probst]

> Are there really going to be any Xquery implementations that don't offer
> the full axis feature? (If not, why is this feature optional?)

I don't know of an implementation that doesn't provide a full axis
feature. However, with some internal data layouts (some numbering
schemes for splitting trees into tables actually) it can be really
difficult to provide those axis in a efficient fashion, so that's
probably why.

Martin