Re: Features and Properties versus Extensions

"David Orchard" <dorchard@bea.com> writes:
> > It seems to me that this is a new data model layered on top
> > of the XML data model, and I'd probably actually want a new
> > query language for it or at least an xpath function.  What
> > I'd really like is to ask "get the property with
> > name=httpauthentication in the binding element and follow the
> > f&p rules to generate it".  Something like
> > "property[@name="httpauthentication"]/binding/operation[@name=
> > "op2"" where the property function evaluates the name in the
> > context that it is given.
> >
> > Is this roughly right?
>
> I think this is perhaps an interesting direction to think about, but
> certainly not necessary to make the model useful.  WSDL itself, as many
> application dialects are, seems to be "a new data model layered on top
> of the XML data model", no?

IMO the simplest way to provide an XPath query language for F&P
is to add an XPath extension as DaveO suggests, but not at the
top level:

/definitions/binding/operation[@name="op2"]/x:property("httpauthentication")

The semantics of x:property(string) can be defined to navigate the
"parent" hierarchy of properties.

Another option is to introduce an extension axis for properties, but that's
a bit more complicated .. esp. for users.

No, I'm not suggesting that WSDL define any such query mechanisms.

Sanjiva.