Serialization of XDM

[Michael Kay]

> On the other hand, it seems to me that we already have such a 
> serialization format, and it's XQuery itself - or rather the 
> subset that involves literals, sequence "constructor" (i.e. 
> comma operator), and direct element/attribute/namespace/text 
> constructors. It's as portable as it gets - any XQuery 
> processor can immediately parse it.
> And it doesn't seem to be missing anything from XDM, either.

For some use cases it's important that the format be canonical: that is,
there should only be one way of representing a given sequence.

Also, XQuery doesn't have any direct way of representing the type annotation
on a node: the closest you can get is a validate{} instruction, and the
effect of this is very context-dependent.

Incidentally, one deficiency of the Saxon -wrap format that I mentioned
earlier is that it doesn't contain any information about node identity. If
you have a sequence of three elements with the same name and content, it
won't tell you whether the sequence being serialized contains three distinct
nodes, or a single node repeated three times.

Regards,

Michael Kay
http://www.saxonica.com/
http://twitter.com/michaelhkay