anchor.diff:  keyTTL returns [String retval]     		   : {isKeyword(input, "TTL")}? id=ID {retval = $id.text;};
   
   // retval is used with these
  +keyNOT returns [String retval]                     : {isKeyword(input, "NOT")}? id=ID {retval = $id.text;};
  +keySYSTEM returns [String retval]                  : {isKeyword(input, "SYSTEM")}? id=ID {retval = $id.text;};
   keyTEMP returns [String retval]                    : {isKeyword(input, "TEMP")}? id=ID {retval = $id.text;};
  -keySYSTEM returns [String retval]                  : {isKeyword(input, "SYSTEM")}? id=ID {retval = $id.text;};
   keyUNMAPPED returns [String retval]                : {isKeyword(input, "UNMAPPED")}? id=ID {retval = $id.text;};
  -keyNOT returns [String retval]                     : {isKeyword(input, "NOT")}? id=ID {retval = $id.text;};
   
   keyADD                          : {isKeyword(input, "ADD")}? ID;
   keyALIAS                        : {isKeyword(input, "ALIAS")}? ID;
  
positive.code: import org.apache.expreval.expr.nullcomp.*;
  import org.apache.expreval.expr.stringpattern.*;
  import org.apache.expreval.expr.var.*;
  import org.apache.expreval.util.*;
  }
  
  @lexer::header {
  
negative.code: import org.apache.hadoop.hbase.hbql.statement.select.*;
  import org.apache.hadoop.hbase.hbql.executor.*;
  import org.apache.hadoop.hbase.hbql.mapping.*;
  import org.apache.hadoop.hbase.hbql.util.*;
  
  import org.apache.expreval.expr.*;
  import org.apache.expreval.expr.node.*;
  