Algernon Tutorial 3.d
Backward chaining rules

These exercises and examples use the newspaper project included in the examples folder of your Protege installation.

Backward chaining rules

((:add-rule Articles
   ((overdue ?article true)
    <-
    (date-due ?article ?duedate)
    (:DATE ?date ?time)
    (:test (:LISP (after-date ?duedate ?date)))
    )))

((:add-rule Nodes
   ((readyToLaunch ?spacecraft true)
    <-
    (fuelLevel ?spacecraft Full)
    (contains  ?spacecraft ScienceStation)
    (:count ?n ?astronaut (astronaut ?spacecraft ?astronaut))
    (:fail (:neq ?n 7))    ;; or (:test (:LISP (= ?n 7)))
    )))