It's hard for me to imagin what replacements for "actor $CURRENT" might possibly exist, other than to address the actor by its specific internal name, which of course does work, eg:
 
actor leftEye
actor Mag Base 3
actor box_2
actor LIGHT3

If you don't address the actor by name, or by saying "use the currently selected actor", what other method could be used to specify it? To answer my own question the only thing I can think of would be "actor $ALL", but I doubt that's implimented.

Les: I can’t imagin it.
kuroyume0161: That is why you fail.