[jsdl-wg] Proposed Extension draft document

[Donal K. Fellows]

Michel Drescher wrote:
> Yes I know. Both alternatives -- abstract types and substitutionGroups 
> -- are functionally equivalent. So whichever fits best current tooling 
> (the draft is in quite early stage, though) should be used in the 
> extension. I have no preference, really.
> 
> On the other hand, the substitutionGroup technique requires you to 
> define a default assignment function. I think there is no default 
> assignment function that would be applicable here.

Actually, it doesn't. If the default is an abstract element, then people
have to use the subtypes/elements instead. And it tools up correctly
with at least one (Axis 1.3).

> Hence the example does not omit the SweepGroup element -- "SweepGroup" 
> is an XML Schema group that does not render element start and end tags.
> Again, if tooling does not support that very well if at all, it is a 
> matter of seconds to change that to a plain old contain er element.

Hmm, I'd be tempted to leave the type out then. Cuts confusion for us
bears of little brain. :-)

> The "Parameter" element's value is a XPath expression. So it may 
> evaluate to an attribute's value or element value. If the assignment 
> function is chosen wisely, then it yields strings that contain XML 
> snippets. This way, you can sweep over EPRs...

I'd rather define the assignment values themselves to be XML chunks
otherwise there's the whole question of how much quoting has to be done
to assemble a string containing (in infoset space) <> characters.

Donal.