[Versa] Issue 3

[Michael Olson]

>>> So, 1 and 2 we have already.  3 would require promoting statements to
>>> first class Versa datatypes (which I think would have benefits - but
>>> how would statement data types work with the other data types for
>>> conversion to and from, etc..).  4 would just be an extension of the
>>> traversal syntax and would solve the original problem.
>>>
>>
>> What if statement datatypes were the results of a traversal?  Then
>> different functions to convert to the different pieces of the
>> statements.
>>
>> subject(* - rdf:type -> rdf:Property)   would be the set of all
>> resources in the system that are properties.
>
> I thought of this, but I'm vexed by the question of whether those
> subexpressions should all be match lists, or whether object should  
> still
> be a functional predicate.  You take the former approach in your
> example.
>
> Either way, again, it's a backward incompatible change, and calls for
> 2.0.
>

What I don't like about this approach is that if all you want is the  
objects, conceptually, and until we get a good optimizer, you get the  
statements (lots of data) just to trim it back to objects.....


Mike

>
>>> I think if you promote statements to first class objects then you  
>>> also
>>> expose statementUri's and Scopes/Context to Versa.  Currently I can
>>> only expose (or filter by) scopes with the explicit use of a scope
>>> function, however if you model statements as first class objects with
>>> the following properties:
>>>
>>
>> Just wanted to add that context/scope are 4RDF'isms so they should be
>> extension functions to versa.
>
> Well, most engines out there support some context/scope/named-subgraph
> capability, so they're far more than just 4RDFisms.  The idea is also
> there in shadow form in SPQRQL (in the form of named subgraphs).
>
> Despite that, I agree that they should be extensions, just to help keep
> Versa core simpler.
>
>
> --  
> Uche Ogbuji                               Fourthought, Inc.
> http://uche.ogbuji.net                    http://fourthought.com
> http://copia.ogbuji.net                   http://4Suite.org
> Use CSS to display XML, part 2 -  
> http://www-128.ibm.com/developerworks/edu/x-dw-x-xmlcss2-i.html
> XML Output with 4Suite & Amara -  
> http://www.xml.com/pub/a/2005/04/20/py-xml.html
> Use XSLT to prepare XML for import into OpenOffice Calc -  
> http://www.ibm.com/developerworks/xml/library/x-oocalc/
> Schema standardization for top-down semantic transparency -  
> http://www-128.ibm.com/developerworks/xml/library/x-think31.html
>
------------------------------------------------------------------------ 
-----------------
Mike Olson                                                Principal  
Consultant
mike.olson at fourthought.com                +1 720 253 4662
Fourthought, Inc.                                       
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