anchor.diff:  booleanFunctions returns [BooleanValue retval]
   options {backtrack=true; memoize=true;}	
   	: s1=calcExpr n=keyNOT? keyCONTAINS s2=calcExpr		
  -							{retval = new ContainsStmt($s1.retval, ($n.text != null), $s2.retval);}
  -	| s1=calcExpr n=keyNOT? keyLIKE s2=calcExpr 	{retval = new LikeStmt($s1.retval, ($n.text != null), $s2.retval);}
  +							{retval = new ContainsStmt($s1.retval, ($n.retval!=null), $s2.retval);}
  +	| s1=calcExpr n=keyNOT? keyLIKE s2=calcExpr 	{retval = new LikeStmt($s1.retval, ($n.retval!=null), $s2.retval);}
   	| s1=calcExpr n=keyNOT? keyBETWEEN s2=calcExpr keyAND s3=calcExpr		
  -							{retval = new DelegateBetweenStmt($s1.retval, ($n.text != null), $s2.retval, $s3.retval);}
  +							{retval = new DelegateBetweenStmt($s1.retval, ($n.retval!=null), $s2.retval, $s3.retval);}
   	| s1=calcExpr n=keyNOT? keyIN LPAREN l=exprList RPAREN			
  -							{retval = new DelegateInStmt($s1.retval, ($n.text != null), $l.retval);} 
  -	| s1=calcExpr keyIS n=keyNOT? keyNULL		{retval = new DelegateNullCompare(($n.text != null), $s1.retval);}	
  +							{retval = new DelegateInStmt($s1.retval, ($n.retval!=null), $l.retval);} 
  +	| s1=calcExpr keyIS n=keyNOT? keyNULL		{retval = new DelegateNullCompare(($n.retval!=null), $s1.retval);}	
   	;
   
   valueFunctions returns [GenericValue retval]
  
positive.code: keyMAP_FILE_INDEX_INTERVAL returns [String retval] : {isKeyword(input, "MAP_FILE_INDEX_INTERVAL")}? id=ID {retval = $id.text;};
  keyMAX_VERSIONS returns [String retval] 	   : {isKeyword(input, "MAX_VERSIONS")}? id=ID {retval = $id.text;};
  keyTTL returns [String retval]     		   : {isKeyword(input, "TTL")}? id=ID {retval = $id.text;};
  
  keyADD                          : {isKeyword(input, "ADD")}? ID;
  keyALIAS                        : {isKeyword(input, "ALIAS")}? ID;
  
negative.code: 							{retval = new DropQueryExecutorPoolStatement($p.retval, $t.text);}
  	;
  
  indexColumnList returns [List<String> retval]
  @init {retval = Lists.newArrayList();}
  	: a1=indexColumn {retval.add($a1.text);} (COMMA a2=indexColumn {retval.add($a2.text);})*;
  