How to find running processes (OS 9 and OS X)

[Ian Summerfield]

I'm struggling with AppleScript,  basically I just want to make my own "keep
it up" type program.  Before I launch an application using AppleScript
(which works), I want to check it isn't already running.   I can get the
name of every process in AppleScript, or even the creator type, but how do I
pass that information back to revolution?   In Hypercard Applescript could
simply set a card field,  in Revoluion it doesn't seem to work.

Or is there a better way to get the running processes?  Hypercard I could
just check the contents on the "application" menu!  Can I do similar in
Revolution?