Re: WSD WG requests to XML Schema WG

Hi folks!

David Orchard wrote:
> If an older receiver gets the <name xsi:type="nameType2">, how does it
> know that nameType2 is an extension of nameType?  Is there some way of
> saying "because  the receiver knows about nameType1 and it gets an
> element called name, it can ignore anything that is different between
> nameType1 and nameType2?

We had this same issue in a lot of the early SOAP encoding conversations,
and I remember talking through this in detail with Eric Prud'Hommeaux back
in 2000 in the context of object types and inheritance.  We came up with a
parentTypes="" (not sure what we called it tho) attribute which would allow
self-describing inheritance hierarchies for compatible extension types,
though it never went beyond that into any of the WG's.

If you know the schema for <name>, I think it's OK to simply ignore the
xsi:type - assuming what you're receiving is still schema-valid with respect
to the base type, it shouldn't matter if you don't understand the new type.

I believe .NET used to (or maybe still does) *always* ignore the xsi:type
attribute....

--Glen