another problem with proposal B

• From: Peter F. Patel-Schneider <pfpschneider@gmail.com>
• Date: Wed, 8 Mar 2017 21:32:29 -0800
• To: public-sparql-exists@w3.org
• Message-ID: <a5a296a2-5ce4-7f0b-5956-4167fabb996c@gmail.com>

Here is another problem with proposal B.

Both of the following queries are syntactically valid but have undefined results.

SELECT ?x WHERE {
 BIND ( ex:a AS ?x )
 FILTER EXISTS { SELECT (ex:b AS ?x) WHERE { } }
 }

SELECT ?x WHERE {
 BIND ( ex:a AS ?x )
 FILTER EXISTS { SELECT ?x WHERE { BIND (ex:b AS ?x) } }
 }

The following query however does have defined results

SELECT ?x WHERE {
 BIND ( ex:a AS ?x )
 FILTER EXISTS { SELECT ?y WHERE { BIND (ex:b AS ?x) } }
 }

This problem is different from that that added the disallowing of binding to
filter variables at the top level of the EXISTS argument as in

SELECT ?x WHERE {
 BIND ( ex:a AS ?x )
 FILTER EXISTS { BIND (ex:b AS ?x) }
 }

peter

Received on Thursday, 9 March 2017 05:33:04 UTC