Re: A question about Filter Function Expression

As it's a legal extension point, you can't completely ignore 
implementations.

You can talk about "an implementation with no extensions", in which case 
there will be zero results.

     Andy

On 20/12/15 14:11, 韩兴旺 wrote:
> Hi:
>     I want to be sure that , according to SPARQL 1.1 specificition, 
> (do not consider the implementations ), this query SELECT * WHERE {?s 
> ?p ?o  filter(isBlank(?s)) filter(str(?s) = 'nodeID://b10001') } limit 
> 10 must return empty solution(Because the domain of function STR do 
> not contain BlankNode)? And for more examples if filter condition is 
> Regex(?x, '^a'); and if the mapping solution of ?x must be a Literal 
> or it can be a BlankNode or URI?
>     Wish your reply!
>     Your Sincerely
>     Xingwang Han
>
>
> Hi there,
>
> If you ask for JSON or XML results, you'll see that ?s is returned as 
> a bnode so some of this is the presentation of bNodes in the HTML.
> (The TSV format is broken.)
>
> Implementations may add something in any place where the signature 
> does not cover the case, here, STR on a blank node.  It means that a 
> filter may pass more solutions than the basic standard, but not less 
> (well, that was the design in SPARQL 1.0 - it's not so simple in 
> SPARQL 1.1).
>
> Your question is specific to the engine implementation at 
> http://lod.openlinksw.com/sparql
> so you might get a more detailed answer there or in its documentation.
>
>     Andy
>
> On 19/12/15 16:49,  wrote:
> Hi, All :
>     Now, I have a question. Can you help me?
>
>     In sparql 1.1 I find the definition of function str() is that:
>
>
>              17.4.2.5 str
>
>       simple literal STR (literal ltrl)     simple literal STR (IRI rsrc)
>
>     But when I search the query SELECT * WHERE {?s ?p ?o  
> filter(isBlank(?s)) filter(str(?s) = 'nodeID://b10001') } limit 10 ,
>     I think if isBlank(?s)is true, then function str(?s)will not be 
> executed. Because the domin of str do not contain Blank node.
>     I think I will got the empty solution. But when I search this 
> query on the endpoint of *LOD Cloud Cache 
> <http://lod.openlinksw.com/>* on the web site 
> http://lod.openlinksw.com/sparql/,
>     I got the result like the following:
>   s  p  o
> nodeID://b10001  http://www.w3.org/1999/02/22-rdf-syntax-ns#type 
> http://www.w3.org/2002/07/owl#Class
> nodeID://b10001  http://www.w3.org/2002/07/owl#complementOf 
> http://www.w3.org/2002/07/owl#Nothing
>
>
>
>     I fell it is odd, and I want to know why it is so!
>     Thank you very much.
>     Your Best Xingwang
>     Wish your reply.
>