Logic on the button bar works! You can now click a button and it will execute a script from a file.
(Slightly later more info edit)
I've added else's to the script interpreter. I also added a couple of "status" user fields that I can store information about features on. So now, the blue button can make a platform go up and down by being attached to the following script file being called on button_down:
f_1 motion = "m -19 0 0 -1000"
f_1 status1 = 1
f_1 motion = "m -19 500 0 1000"
f_1 status1 = 0