public void outputSQL(StringWriter sw) {
    sw.write(function_name);
    sw.write("(");

    for (Enumeration e = parameters.elements(); e.hasMoreElements(); ) {
      BaseExpression be = (BaseExpression) (e.nextElement());
      be.outputSQL(sw);

      if (e.hasMoreElements()) sw.write(", ");
    }

    sw.write(")");
  }
 @Override
 protected void deepCopy(DuplicateMap map) {
   super.deepCopy(map);
   operands = duplicateList(operands, map);
 }