xml-dev - Re: A certain difficulty

[David Megginson <david@megginson.com>]

Miles Sabin <msabin@cromwellmedia.co.uk> writes:

> If all you're interested in is representing a formal graph
> structure, then fine. But surely to be interesting we have to
> be able to _interpret_ this stuff (I'm intending the contrast
> between 'formal' and 'interpreted' here in the same sense it's
> used in semantic theories).

The idea of using RDF (or any extensible, distributed
object-representation format) is that you can work with partial
knowledge.  RDF allows that in two ways:

1. If you do not recognize a class, it is still possible to recognize
   some of its properties and act accordingly, i.e.

     unrecognized class megg:Foo has a recognized property megg:rating


2. If you don't recognize a class or property, you may recognize one
   of its superclasses or superproperties, and be able to act
   accordingly, i.e.

     unrecognized class megg:Bungalow is a kind of 
       recognized class megg:House
     unrecognized property megg:length is a kind of 
       recognized property megg:linear-measurement

Traditional OO implementations allow only #2; I actually question how
usable #2 will be for distributed XML objects, since it depends very
heavily on schemas, but #1 is clearly useful.


All the best,


David

-- 
David Megginson                 david@megginson.com
           http://www.megginson.com/

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