#old-style

(operator LOAD-TRUCK
  (params
   (<obj> OBJECT)
   (<truck> TRUCK)
   (<loc> LOCATION))
  (preconds
   (at <truck> <loc>) (at <obj> <loc>))
  (effects
   (in <obj> <truck>) (at <truck> <loc>)))

(operator LOAD-AIRPLANE
  (params
   (<obj> OBJECT)
   (<airplane> AIRPLANE)
   (<loc> LOCATION))
  (preconds
   (at <obj> <loc>) (at <airplane> <loc>))
  (effects
   (in <obj> <airplane>) (at <airplane> <loc>)))

(operator UNLOAD-TRUCK
  (params
   (<obj> OBJECT)
   (<truck> TRUCK)
   (<loc> LOCATION))
  (preconds
   (at <truck> <loc>) (in <obj> <truck>))
  (effects
   (at <obj> <loc>) (at <truck> <loc>)))

(operator UNLOAD-AIRPLANE
  (params
   (<obj> OBJECT)
   (<airplane> AIRPLANE)
   (<loc> LOCATION))
  (preconds
   (in <obj> <airplane>) (at <airplane> <loc>))
  (effects
   (at <obj> <loc>) (at <airplane> <loc>)))

(operator DRIVE-TRUCK
  (params
   (<truck> TRUCK)
   (<loc-from> LOCATION)
   (<loc-to> LOCATION)
   (<city> CITY))
  (preconds
   (at <truck> <loc-from>)
   (loc-at <loc-from> <city>)
   (loc-at <loc-to> <city>))
  (effects
   (at <truck> <loc-to>)
   (loc-at <loc-from> <city>)
   (loc-at <loc-to> <city>)))

(operator FLY-AIRPLANE
  (params
   (<airplane> AIRPLANE)
   (<loc-from> AIRPORT)
   (<loc-to> AIRPORT))
  (preconds
   (at <airplane> <loc-from>))
  (effects
   (at <airplane> <loc-to>)))