anchor.diff:  ----
   
   _Example 1B:_
  +Return all nodes with both first name and second name:
   [source, cypher]
   ----
   MATCH (actor)
  -WHERE EXISTS(actor["slogan"])
  +WHERE EXISTS(actor.firstName + actor.lastName)
   RETURN actor
   ----
  -
   
   _Example 2A:_
   
  
positive.code: ----
  
  === Interaction with existing features
  This replaces the pre-existing +has(...)+ function.
  
  == What others do
  
  This is very similar to what SQL does with its EXISTS functionality.
  
  This is also very similar in syntax to what SPARQL does with its EXISTS functionality; the rules regarding identifiers are identical, and the inner query also takes a subquery as input.
  
  == Benefits to this proposal
  
  The existing pattern predicate functionality is very useful, but does not cover all cases.
  Pattern predicates do not allow for introducing identifiers, which makes some queries - such as the one below - difficult to express succinctly:
  
  [source, cypher]
  ----
  
negative.code:            | simple subquery exists
              ;
  
  property exists = "EXISTS", "(", expression ")"
                  ;
  
  subquery exists = "EXISTS", "{", read only clause, { read only clause }, "}" ;
  