[Versa] Question about query

[Michael Olson]

>> My question, is what if this is the top level expression and executed
>> on an empty model.  What are the results of the expression?
>>
>> Is it a boolean?
>>
>> Is it null because the resource does not exist?
>>
>> Is it just the resource's URI regardless of whether or not it exists?
>
> Yes.
>
>> I think it should be the empty set.
>
> Why?
>

Be cause it is a "query".  So I guess my feeling is if we want to  
express

<http://foo.com>

as a versa query, then it needs to be a query.

Same with

true

and to me it is a query of whether or not that resource exists in the  
model.

If we don't want it to be  query, but a "pattern", then we would have  
to change the spec so the above two queries are not valid as top level  
queries, but only valid in filter, traverse, and function calls.


As I said in a previous email, it is on my "need" list to support these  
queries.  If we remove them, then I will have to use an extension  
function.

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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