[Issue 170] Update on EXISTS

The EXISTS CG has two proposals under discussion for fixes to the EXISTS 
feature of SPARQL 1.1

Both address SHACL ISSUE-170 in the same way (by different means). Blank 
nodes passed into EXISTS do not participate in basic graph pattern (BGP) 
nor property path (PP) matching, values of variables are restricted to 
the current row after BGP or PP matching.

ISSUE-68 is not specifically about EXISTS but a revised mechanism for
EXIST may be applicable for what is current called "pre-binding".

Proposal-A has the simpler definition:
https://lists.w3.org/Archives/Public/public-sparql-exists/2016Sep/0012.html

Proposal-B covers more uses of EXISTS:

https://lists.w3.org/Archives/Public/public-sparql-exists/2016Sep/0024.html

    and more fully in:

https://w3c.github.io/sparql-exists/docs/sparql-exists.html#an-alternative-to-substitution

Any input from the SHACL-WG would be appreciated.

 Andy

Received on Sunday, 11 December 2016 13:28:18 UTC