For purposes of discussion, suppose that you arbitrarily split sequence
serialization from single-item serialization into non-XML formats because I
believe they are actually qualitatively different problems. Referring only
to the sequence serialization side of the problem here, I think the question
is whether XML sequence serialization and parsing has to in fact be
consumable by an XML parser. As I see it, you either end up specifying some
arbitrary set of privileged xml sequence tags:
<?xml version="1.0" encoding="UTF-8"?>
<xml:sequence xmlns:xs="http://www.w3.org/2001/XMLSchema">
<xml:item value="foo" type="xs:string"/>
<xml:item value="5" type="xs:positiveInteger"/>
<xml:item type="document"><bar><bat/></bar></xml:item>
<xml:item type="comment">foo</xml:item>
</xml:sequence>
or you work with a direct serialization as described earlier, possibly with
RDF encodings for type:
(<?xml version="1.0"
encoding="UTF-8"?>,"foo",5^positiveInteger,<bar><bat/></bar>,<!-- foo -->)
I agree those are two of the more obvious choices on the table, but using a
negative word "arbitrary" to describe one, and a positive word "direct" to
describe the other, seems to be prejudging which is a better fit to the
requirements of the use cases, without actually stating any rationale.
Regards,
Michael Kay
http://www.saxonica.com/
http://twitter.com/michaelhkay