what number to use in reactor set active mode

I am trying to set the active mode based on the track name. I have a reactor that responds to a change in track name, and it can set the active mode, but the function to set the active mode only takes a number.  I have not found an easy way to discover the number associated with a given mode. Is there a way to see the mapping? Or even better, a command to get the number based on the mode name?

using css :Version 3.0.1