Existential Subsequence

[Michael Burbidge]

The tkl test suite contains the following query:

MATCH (n) WHERE exists {
(n)-->()
}
RETURN n

In this query contains the following expression: "exists {(n)-->()}" Or at least according to the grammar WHERE should be followed by an expression.

But I cannot see how "exists {(n)-->()}" is a valid expression according to the grammar. "EXIST" is a valid function name according to https://s3.amazonaws.com/artifacts.opencypher.org/railroad/FunctionInvocation.html. But the function name is to be followed by '(', not '{'.

Can someone point me to the railroad diagram that defines the part of the expression grammar that addresses this expression?

Thanks,

Michael-

[Hannes Voigt]

Hi Michael,

EXIST subqueries are described in a CIP:

https://github.com/opencypher/openCypher/blob/master/cip/1.accepted/CIP2015-05-13-EXISTS.adoc

The related grammar production should be

https://raw.githack.com/openCypher/openCypher/master/tools/grammar-production-links/grammarLink.html?p=ExistentialSubquery (which is an Atom).

Cheers 

-Hannes

--
You received this message because you are subscribed to the Google Groups "openCypher" group.
To unsubscribe from this group and stop receiving emails from it, send an email to opencypher+...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/opencypher/9550fc15-4d3d-48e1-9262-918ec408b599n%40googlegroups.com.

[Michael Burbidge]

Thank you Hannes. I'm new to the openCypher process, forgive me if I'm asking a question that has an obvious answer. It looks like CIPs are proposals that go through various stages and review and are finally merged. It's not clear from the README whether Accepted proposals have been merged or are just accepted for review. And the question I have is why are the test cases for this merged but not the grammar changes?

Michael-