Inheritance in XML [^*]

Lisa Rein lisarein at
Thu Apr 23 22:22:30 BST 1998

> What are two properties? Type and class? Did you shift from discussing
> properties "concerning" type and class and type and class *as* properties.
> Can you also please defend the distinction between type and class? It
> makes sense in object oriented programming languages (mostly for
> performance reasons), but I don't know that there is any such distinction
> in common usage or in most ontologies. I am prepared to be convinced
> otherwise, but I think that the class/type distinction is specific to OOP
> and is not useful except as an arbitrary distinction, to avoid confusion,
> as it is used in the DSSSL spec. (node class, flow object class vs.
> element type ... you could as easily reverse them and talk of element
> classes and node types...)

It was my understanding that they are all just different names for the
same "things".  At least they are for RDF, right?  In fact, in the RDF
Schema group, as far as the typing (classing) models were concerned,
types and classes were exactly the same (so much so, in fact, that we
went back and forth on which to call them and, conceptually anyway, the
words became so interchangible -- Resulting in a "type system" of
classes :-).  Also, the types/classes and their respective resources (of
which RDF's mission is to describe) WERE classes and node types (that
was my understanding anyway...).

Just when I thought I finally had a clear understanding of the above,
suddenly I'm not so sure.  Someone reassure me....please.


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