Do you mean the UI rule editor? If so, this is currently not implemented. You have some options though…
- Use scripted automation rather than the UI rule editor
- Use the ‘execute a given script’ Action, which is basically #1 but as a ScriptedAction
Either way, you can use the new rule engine, scripted automation, Jython, and the helper libraries to do something like what is documented here… Actions — openHAB Helper Libraries documentation.