Revelation are gearing up for the release of 9.1.1 shortly and part of this upgrade will be a request made at the recent EMEA RUG meeting in London.
Changes have been made to TCL in the new version. These enhancements will enable developers to limit certain commands so that they can not be run by a particular user. For example, you will be able to expose TCL to your users and at the same time you could restrict access to the CLEARFILE command.
This neat change to TCL will enable users to make better use of TCL, without the application author having to worry about the integrity of the system being compromised in any way.