According to FMP 15 documentation,
"A local variable can only be used in script steps in the currently executing script. The value in a local variable is cleared when the script exits."
But my question concerns something just slightly different, namely, is a variable local or global when it's referenced in "Perform script"?
1) Set variable fileName; "Export_file"
2) Perform script "File export"
So in this case, must the variable be "$$fileName" rather than "$fileName," even if there's no Exit script step within the subscript being referred to, "File export"?