various issues

Digitome Ltd digitome at
Fri Apr 11 18:12:15 BST 1997

>Peter Murray-Rust writes:
 > I think I start to understand.  By 'structure' you mean the tree structure
 > of each DTD?  In which case AFs are a way of providing multiple views of the
 > same document?

An AF is like a virtual class in OO-speak. HyTime is a bit like a set of 
virtual class definitions. From these virtual classes you derive your own
classes (DTDs) that inherit from their super-class(HyTime).

Multiple inheritance is allowwed. That is, a given DTD can inherit from
multiple AF super-classes.

I am on dodgier ground now but I think AF's are virtual rather than pure virtual
classes. I.e.  an AF can be a DTD if you want it to.

Hope this helps,


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