You can’t. Only AppleScript is supported in the smart rule’s Execute Script action.
Also, the solution is much simpler than all that 
Use this form in Script Editor and you can test the Execute Script function on a selection…
tell application id "DNtp"
set sel to (selection as list)
my performSmartRule(sel)
end tell
on performSmartRule(theRecords)
tell application id "DNtp"
repeat with theRecord in theRecords
-- Do stuff
end repeat
end tell
end performSmartRule