RE: Types and Context

[Jonathan Borden <jborden@mediaone.net>]

Simon St.Laurent wrote:

>
> Sure thing.  Now do that with <foo myInt="123"/> and tell me what it
> looks like.

it starts to look complicated, for example Richard Tobin's XML Schema for
the XML Infoset defines such an XML Syntax (akin to XSet). The issue is that
to represent an attribute in XML you can expand the XML into elements
labelled by their corresponding productions e.g.

<element>
	<Name>foo</Name>
	<Attribute>
		<Name>myInt</Name>
		<Value>123</Value>
		<xsi:type>simons:integer</xsi:type>
	</Attribute>
</element>


>
> > the reason that the "typeOf" function is more interesting is that it
> > "understands" the type hierarchy so that the test:
> >
> > typeOf(node, "simonsVeryOwn:integer") and
> > typeOf(node, "xsd:integer") both might be true, yet simply
> testing the value
> > of a type adorning attribute doesn't tell us this.
>
> Again, I'd be a lot happier if there was an XML-based syntax for
> describing that type hierarchy, rather than an API for dealing with it.
> That type information might also be more logically associated with the
> stylesheet than with the document.

well there are a number of XML syntaxes to describe type hierarchies
including:

XML Schema
RDF (Schema)
DAML+OIL
RELAXNG
Schematron
etc.

The point about the "typeOf" function, and the schema algebra (which is a
purely function/predicate based description) is that it is schema syntax
independent, and thus, theoretically, enables plug and play schemata.

-Jonathan