anchor.diff:      ;
   
   argList
  -    : ( nil | OPEN_BRACE DISTINCT? expression ( COMMA expression )* CLOSE_BRACE ) -> DISTINCT? nil* expression*
  +    : nil -> nil
  +    | OPEN_BRACE DISTINCT? expression ( COMMA expression )* CLOSE_BRACE -> DISTINCT? expression*
       ;
   
   expressionList
  
positive.code:     ;
  
  constraint
      : brackettedExpression | builtInCall | functionCall
      ;
  
  functionCall
  
negative.code: 	
  triplesNode
      : OPEN_BRACE graphNode+ CLOSE_BRACE -> ^(COLLECTION graphNode+)
      | lsb=OPEN_SQUARE_BRACKET propertyListNotEmpty[new CommonTree(new CommonToken(VAR,"[]"))] CLOSE_SQUARE_BRACKET -> ^(VAR[$lsb,"[]"] propertyListNotEmpty)
      ;
  
  graphNode
  