String getFuncText(String funcText, final int srcPos) {
      if (srcPos == 0) {
        return funcText;
      }

      return FunctionRegistry.invertFuncText(funcText);
    }
creates synthetic predicates that represent "IN (keylist other table)"
ql/src/java/org/apache/hadoop/hive/ql/ppd/SyntheticJoinPredicate.java