[Versa] Issue 1, better literal and datatype support

[Michael Olson]

I'd like to propose adding better literal and data type support to  
Versa.  I don't think we need to do too much to the spec itself to  
support this.  One thing we need is a literal data type.  This would be  
a representation of a plain (with or without language) or typed  
literal.  I think we leave hard issues like comparison and sorting  
between typed literals to the underlying model.  If the model support  
D-entailment then it can properly compare "01"^^xsd:int and  
"1"^^xsd:int.  If it doesn't....

Besides the addition of the literal datatype, I think all that is  
needed is to determine how the conversions work (should be pretty  
straight forward) and some functions.  ie. it would be nice to filter  
on language and/or datatype in a traversal.

One last thing, we would need to allow these literals as "subjects" in  
traversals.  This does not mean much from the specification point of  
view, maybe just a mention, but implementors will need to understand  
this.

Mike



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Mike Olson                                                Principal  
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mike.olson at fourthought.com                +1 720 253 4662
Fourthought, Inc.                                       
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