neo4j/neo4j — pull request #1458 by systay (2013-11-12 13:33:33+00:00)
Title: Introduce ternary logic in Cypher

o Make Predicate return Option[Boolean] instead of Boolean
o Introduce isTrue that returns false for all cases except when the
predicate returns Some(true)
o Add logic for IN, ANY, ALL, SINGLE and NONE to handle nulls
o Add a new section on working with nulls to the manual