function name as an argument

[Boyin Huang]

I know that I can pass an variable into a script by using script argument,
or by using a global-variable name.

My question is: Can we pass a function name (defined in *.gsf)into a
script?

For example, I have two rainbow definition rb1 and rb2, and I want to use
different rainbows in different plots. So it would be convient if I can
pass the function name (rb1 or rb2) into a pre-written plotting script.