(deftemp Animal (slot loc (default greencouch)) (slot on-top-of (default roof)) (slot hold (default nothing))) (deftemp thing (slot name (default NONE)) (slot loc (default NONE)) (slot on-top-of (default roof)) (slot mass (default light weight))) (deftemp chest (slot name (default NONE)) (slot contents (default NONE)) (slot unlocked-by (default NONE))) (deftemp goal-was (slot act (default NONE)) (multislot args)) (defrule hold chest to get of roof \"\" (goal-was (act unlock) (args ?chest)) (thing (name ?chest) (on-top-of ~roof) (mass light weight)) (Animal (hold ~?chest)) (not (goal-was (act hold) (args ?chest))) => (assert (goal-was (act hold) (args ?chest)))) (defrule put-chest-on-roof \"\" (goal-was (act unlock) (args ?chest)) ?Animal <- (Animal (loc ?place) (on-top-of ?on) (hold ?chest)) ?thing <- (thing (name ?chest)) => (printout t \"Animal throws the \" ?chest \" off the \" ?on \" onto the roof.\" crlf) (modify ?Animal (hold blank)) (modify ?thing (loc ?place) (on-top-of roof))) (defrule get-key-to-unlock \"\" (goal-was (act unlock) (args ?obj)) (thing (name ?obj) (on-top-of roof)) (chest (name ?obj) (unlocked-by ?key)) (Animal (hold ~?key)) (not (goal-was (act hold) (args ?key))) => (assert (goal-was (act hold) (args ?key)))) (defrule move-to-chest-with-key \"\" (goal-was (act unlock) (args ?chest)) (Animal (loc ?mplace) (hold ?key)) (thing (name ?chest) (loc ?cplace&~?mplace) (on-top-of roof)) (chest (name ?chest) (unlocked-by ?key)) (not (goal-was (act walk-to) (args ?cplace))) => (assert (goal-was (act walk-to) (args ?cplace)))) (defrule unlock-chest-with-key \"\" ?goal <- (goal-was (act unlock) (args ?name)) ?chest <- (chest (name ?name) (contents ?contents) (unlocked-by ?key)) (thing (name ?name) (loc ?place) (on-top-of ?on)) (Animal (loc ?place) (on-top-of ?on) (hold ?key)) => (printout t \"Animal opens the \" ?name \" with the \" ?key \" revealing the \" ?contents \".\" crlf) (modify ?chest (contents nothing)) (assert (thing (name ?contents) (loc ?place) (on-top-of ?name))) (retract ?goal)) ;;;********************* ;;;* HOLD OBJECT RULES * ;;;********************* (defrule unlock-chest-to-hold-object \"\" (goal-was (act hold) (args ?obj)) (chest (name ?chest) (contents ?obj)) (not (goal-was (act unlock) (args ?chest))) => (assert (goal-was (act unlock) (args ?chest)))) (defrule use-ladder-to-hold \"\" (goal-was (act hold) (args ?obj)) (thing (name ?obj) (loc ?place) (on-top-of ceiling) (mass light weight)) (not (thing (name ladder) (loc ?place))) (not (goal-was (act move) (args ladder ?place))) => (assert (goal-was (act move) (args ladder ?place)))) (defrule climb-ladder-to-hold \"\" (goal-was (act hold) (args ?obj)) (thing (name ?obj) (loc ?place) (on-top-of ceiling) (mass light weight)) (thing (name ladder) (loc ?place) (on-top-of roof)) (Animal (on-top-of ~ladder)) (not (goal-was (act on) (args ladder))) => (assert (goal-was (act on) (args ladder)))) (defrule grab-object-from-ladder \"\" ?goal <- (goal-was (act hold) (args ?.

1. (deftemp Animal
(slot loc
(default greencouch))
(slot on-top-of
(default roof))
(slot hold
(default nothing)))
(deftemp thing
(slot name
(default NONE))
(slot loc
(default NONE))
(slot on-top-of
(default roof))
(slot mass
(default light weight)))
(deftemp chest
(slot name
(default NONE))
(slot contents
(default NONE))
(slot unlocked-by
(default NONE)))
(deftemp goal-was
(slot act
(default NONE))
(multislot args))
(defrule hold chest to get of roof ""
(goal-was (act unlock) (args ?chest))
(thing (name ?chest) (on-top-of ~roof) (mass light weight))
(Animal (hold ~?chest))
(not (goal-was (act hold) (args ?chest)))

2. =>
(assert (goal-was (act hold) (args ?chest))))
(defrule put-chest-on-roof ""
(goal-was (act unlock) (args ?chest))
?Animal <- (Animal (loc ?place) (on-top-of ?on) (hold ?chest))
?thing <- (thing (name ?chest))
=>
(printout t "Animal throws the " ?chest " off the "
?on " onto the roof." crlf)
(modify ?Animal (hold blank))
(modify ?thing (loc ?place) (on-top-of roof)))
(defrule get-key-to-unlock ""
(goal-was (act unlock) (args ?obj))
(thing (name ?obj) (on-top-of roof))
(chest (name ?obj) (unlocked-by ?key))
(Animal (hold ~?key))
(not (goal-was (act hold) (args ?key)))
=>
(assert (goal-was (act hold) (args ?key))))
(defrule move-to-chest-with-key ""
(goal-was (act unlock) (args ?chest))
(Animal (loc ?mplace) (hold ?key))
(thing (name ?chest) (loc ?cplace&~?mplace) (on-top-of roof))
(chest (name ?chest) (unlocked-by ?key))
(not (goal-was (act walk-to) (args ?cplace)))
=>
(assert (goal-was (act walk-to) (args ?cplace))))
(defrule unlock-chest-with-key ""
?goal <- (goal-was (act unlock) (args ?name))
?chest <- (chest (name ?name) (contents ?contents) (unlocked-by ?key))
(thing (name ?name) (loc ?place) (on-top-of ?on))
(Animal (loc ?place) (on-top-of ?on) (hold ?key))
=>
(printout t "Animal opens the " ?name " with the " ?key
" revealing the " ?contents "." crlf)
(modify ?chest (contents nothing))

3. (assert (thing (name ?contents) (loc ?place) (on-top-of ?name)))
(retract ?goal))
;;;*********************
;;;* HOLD OBJECT RULES *
;;;*********************
(defrule unlock-chest-to-hold-object ""
(goal-was (act hold) (args ?obj))
(chest (name ?chest) (contents ?obj))
(not (goal-was (act unlock) (args ?chest)))
=>
(assert (goal-was (act unlock) (args ?chest))))
(defrule use-ladder-to-hold ""
(goal-was (act hold) (args ?obj))
(thing (name ?obj) (loc ?place) (on-top-of ceiling) (mass light weight))
(not (thing (name ladder) (loc ?place)))
(not (goal-was (act move) (args ladder ?place)))
=>
(assert (goal-was (act move) (args ladder ?place))))
(defrule climb-ladder-to-hold ""
(goal-was (act hold) (args ?obj))
(thing (name ?obj) (loc ?place) (on-top-of ceiling) (mass light weight))
(thing (name ladder) (loc ?place) (on-top-of roof))
(Animal (on-top-of ~ladder))
(not (goal-was (act on) (args ladder)))
=>
(assert (goal-was (act on) (args ladder))))
(defrule grab-object-from-ladder ""
?goal <- (goal-was (act hold) (args ?name))
?thing <- (thing (name ?name) (loc ?place)
(on-top-of ceiling) (mass light weight))
(thing (name ladder) (loc ?place))
?Animal <- (Animal (loc ?place) (on-top-of ladder) (hold blank))
=>
(printout t "Animal grabs the " ?name "." crlf)
(modify ?thing (loc held) (on-top-of held))
(modify ?Animal (hold ?name))

4. (retract ?goal))
(defrule climb-to-hold ""
(goal-was (act hold) (args ?obj))
(thing (name ?obj) (loc ?place) (on-top-of ?on&~ceiling) (mass light weight))
(Animal (loc ?place) (on-top-of ~?on))
(not (goal-was (act on) (args ?on)))
=>
(assert (goal-was (act on) (args ?on))))
(defrule walk-to-hold ""
(goal-was (act hold) (args ?obj))
(thing (name ?obj) (loc ?place) (on-top-of ~ceiling) (mass light weight))
(Animal (loc ~?place))
(not (goal-was (act walk-to) (args ?place)))
=>
(assert (goal-was (act walk-to) (args ?place))))
(defrule drop-to-hold ""
(goal-was (act hold) (args ?obj))
(thing (name ?obj) (loc ?place) (on-top-of ?on) (mass light weight))
(Animal (loc ?place) (on-top-of ?on) (hold ~blank))
(not (goal-was (act hold) (args blank)))
=>
(assert (goal-was (act hold) (args blank))))
(defrule grab-object ""
?goal <- (goal-was (act hold) (args ?name))
?thing <- (thing (name ?name) (loc ?place)
(on-top-of ?on) (mass light weight))
?Animal <- (Animal (loc ?place) (on-top-of ?on) (hold blank))
=>
(printout t "Animal grabs the " ?name "." crlf)
(modify ?thing (loc held) (on-top-of held))
(modify ?Animal (hold ?name))
(retract ?goal))
(defrule drop-object ""
?goal <- (goal-was (act hold) (args blank))
?Animal <- (Animal (loc ?place)
(on-top-of ?on)

5. (hold ?name&~blank))
?thing <- (thing (name ?name))
=>
(printout t "Animal drops the " ?name "." crlf)
(modify ?Animal (hold blank))
(modify ?thing (loc ?place) (on-top-of ?on))
(retract ?goal))
;;;*********************
;;;* MOVE OBJECT RULES *
;;;*********************
(defrule unlock-chest-to-move-object ""
(goal-was (act move) (args ?obj ?))
(chest (name ?chest) (contents ?obj))
(not (goal-was (act unlock) (args ?chest)))
=>
(assert (goal-was (act unlock) (args ?chest))))
(defrule hold-object-to-move ""
(goal-was (act move) (args ?obj ?place))
(thing (name ?obj) (loc ~?place) (mass light weight))
(Animal (hold ~?obj))
(not (goal-was (act hold) (args ?obj)))
=>
(assert (goal-was (act hold) (args ?obj))))
(defrule move-object-to-place ""
(goal-was (act move) (args ?obj ?place))
(Animal (loc ~?place) (hold ?obj))
(not (goal-was (act walk-to) (args ?place)))
=>
(assert (goal-was (act walk-to) (args ?place))))
(defrule drop-object-once-moved ""
?goal <- (goal-was (act move) (args ?name ?place))
?Animal <- (Animal (loc ?place) (hold ?obj))
?thing <- (thing (name ?name) (mass light weight))
=>
(printout t "Animal drops the " ?name "." crlf)
(modify ?Animal (hold blank))

6. (modify ?thing (loc ?place) (on-top-of roof))
(retract ?goal))
(defrule already-moved-object ""
?goal <- (goal-was (act move) (args ?obj ?place))
(thing (name ?obj) (loc ?place))
=>
(retract ?goal))
;;;***********************
;;;* WALK TO PLACE RULES *
;;;***********************
(defrule already-at-place ""
?goal <- (goal-was (act walk-to) (args ?place))
(Animal (loc ?place))
=>
(retract ?goal))
(defrule get-on-roof-to-walk ""
(goal-was (act walk-to) (args ?place))
(Animal (loc ~?place) (on-top-of ~roof))
(not (goal-was (act on) (args roof)))
=>
(assert (goal-was (act on) (args roof))))
(defrule walk-hold-nothing ""
?goal <- (goal-was (act walk-to) (args ?place))
?Animal <- (Animal (loc ~?place) (on-top-of roof) (hold blank))
=>
(printout t "Animal walks to " ?place "." crlf)
(modify ?Animal (loc ?place))
(retract ?goal))
(defrule walk-hold-object ""
?goal <- (goal-was (act walk-to) (args ?place))
?Animal <- (Animal (loc ~?place) (on-top-of roof) (hold ?obj&~blank))
=>
(printout t "Animal walks to " ?place " hold the " ?obj "." crlf)
(modify ?Animal (loc ?place))
(retract ?goal))
;;;***********************

7. ;;;* GET ON OBJECT RULES *
;;;***********************
(defrule jump-onto-roof ""
?goal <- (goal-was (act on) (args roof))
?Animal <- (Animal (on-top-of ?on&~roof))
=>
(printout t "Animal jumps off the " ?on " onto the roof." crlf)
(modify ?Animal (on-top-of roof))
(retract ?goal))
(defrule walk-to-place-to-climb ""
(goal-was (act on) (args ?obj))
(thing (name ?obj) (loc ?place))
(Animal (loc ~?place))
(not (goal-was (act walk-to) (args ?place)))
=>
(assert (goal-was (act walk-to) (args ?place))))
(defrule drop-to-climb ""
(goal-was (act on) (args ?obj))
(thing (name ?obj) (loc ?place))
(Animal (loc ?place) (hold ~blank))
(not (goal-was (act hold) (args blank)))
=>
(assert (goal-was (act hold) (args blank))))
(defrule climb-indirectly ""
(goal-was (act on) (args ?obj))
(thing (name ?obj) (loc ?place) (on-top-of ?on))
(Animal (loc ?place) (on-top-of ~?on&~?obj) (hold blank))
(not (goal-was (act on) (args ?on)))
=>
(assert (goal-was (act on) (args ?on))))
(defrule climb-directly ""
?goal <- (goal-was (act on) (args ?obj))
(thing (name ?obj) (loc ?place) (on-top-of ?on))
?Animal <- (Animal (loc ?place) (on-top-of ?on) (hold blank))
=>
(printout t "Animal climbs onto the " ?obj "." crlf)

8. (modify ?Animal (on-top-of ?obj))
(retract ?goal))
(defrule already-on-object ""
?goal <- (goal-was (act on) (args ?obj))
(Animal (on-top-of ?obj))
=>
(retract ?goal))
;;;********************
;;;* EAT OBJECT RULES *
;;;********************
(defrule hold-to-eat ""
(goal-was (act eat) (args ?obj))
(Animal (hold ~?obj))
(not (goal-was (act hold) (args ?obj)))
=>
(assert (goal-was (act hold) (args ?obj))))
(defrule satisfy-hunger ""
?goal <- (goal-was (act eat) (args ?name))
?Animal <- (Animal (hold ?name))
?thing <- (thing (name ?name))
=>
(printout t "Animal eats the " ?name "." crlf)
(modify ?Animal (hold blank))
(retract ?goal ?thing))
;;;**********************
;;;* INITIAL STATE *
;;;**********************
(deffacts startup ""
(Animal (loc t5-7) (on-top-of greencouch) (hold blank))
(thing (name greencouch) (loc t5-7) (mass heavy))
(thing (name red-couch) (loc t2-2) (mass heavy))
(thing (name big-pillow) (loc t2-2) (on-top-of red-couch))
(thing (name red-chest) (loc t2-2) (on-top-of big-pillow))
(chest (name red-chest) (contents ladder) (unlocked-by red-key))
(thing (name blue-chest) (loc t7-7) (on-top-of ceiling))
(chest (name blue-chest) (contents bananas) (unlocked-by blue-key))

9. (thing (name blue-couch) (loc t8-8) (mass heavy))
(thing (name green-chest) (loc t8-8) (on-top-of ceiling))
(chest (name green-chest) (contents blue-key) (unlocked-by red-key))
(thing (name red-key) (loc t1-3))
(goal-was (act eat) (args bananas)))
Solution
(deftemp Animal
(slot loc
(default greencouch))
(slot on-top-of
(default roof))
(slot hold
(default nothing)))
(deftemp thing
(slot name
(default NONE))
(slot loc
(default NONE))
(slot on-top-of
(default roof))
(slot mass
(default light weight)))
(deftemp chest
(slot name
(default NONE))
(slot contents
(default NONE))
(slot unlocked-by
(default NONE)))
(deftemp goal-was
(slot act
(default NONE))

10. (multislot args))
(defrule hold chest to get of roof ""
(goal-was (act unlock) (args ?chest))
(thing (name ?chest) (on-top-of ~roof) (mass light weight))
(Animal (hold ~?chest))
(not (goal-was (act hold) (args ?chest)))
=>
(assert (goal-was (act hold) (args ?chest))))
(defrule put-chest-on-roof ""
(goal-was (act unlock) (args ?chest))
?Animal <- (Animal (loc ?place) (on-top-of ?on) (hold ?chest))
?thing <- (thing (name ?chest))
=>
(printout t "Animal throws the " ?chest " off the "
?on " onto the roof." crlf)
(modify ?Animal (hold blank))
(modify ?thing (loc ?place) (on-top-of roof)))
(defrule get-key-to-unlock ""
(goal-was (act unlock) (args ?obj))
(thing (name ?obj) (on-top-of roof))
(chest (name ?obj) (unlocked-by ?key))
(Animal (hold ~?key))
(not (goal-was (act hold) (args ?key)))
=>
(assert (goal-was (act hold) (args ?key))))
(defrule move-to-chest-with-key ""
(goal-was (act unlock) (args ?chest))
(Animal (loc ?mplace) (hold ?key))
(thing (name ?chest) (loc ?cplace&~?mplace) (on-top-of roof))
(chest (name ?chest) (unlocked-by ?key))
(not (goal-was (act walk-to) (args ?cplace)))
=>
(assert (goal-was (act walk-to) (args ?cplace))))
(defrule unlock-chest-with-key ""
?goal <- (goal-was (act unlock) (args ?name))

11. ?chest <- (chest (name ?name) (contents ?contents) (unlocked-by ?key))
(thing (name ?name) (loc ?place) (on-top-of ?on))
(Animal (loc ?place) (on-top-of ?on) (hold ?key))
=>
(printout t "Animal opens the " ?name " with the " ?key
" revealing the " ?contents "." crlf)
(modify ?chest (contents nothing))
(assert (thing (name ?contents) (loc ?place) (on-top-of ?name)))
(retract ?goal))
;;;*********************
;;;* HOLD OBJECT RULES *
;;;*********************
(defrule unlock-chest-to-hold-object ""
(goal-was (act hold) (args ?obj))
(chest (name ?chest) (contents ?obj))
(not (goal-was (act unlock) (args ?chest)))
=>
(assert (goal-was (act unlock) (args ?chest))))
(defrule use-ladder-to-hold ""
(goal-was (act hold) (args ?obj))
(thing (name ?obj) (loc ?place) (on-top-of ceiling) (mass light weight))
(not (thing (name ladder) (loc ?place)))
(not (goal-was (act move) (args ladder ?place)))
=>
(assert (goal-was (act move) (args ladder ?place))))
(defrule climb-ladder-to-hold ""
(goal-was (act hold) (args ?obj))
(thing (name ?obj) (loc ?place) (on-top-of ceiling) (mass light weight))
(thing (name ladder) (loc ?place) (on-top-of roof))
(Animal (on-top-of ~ladder))
(not (goal-was (act on) (args ladder)))
=>
(assert (goal-was (act on) (args ladder))))
(defrule grab-object-from-ladder ""
?goal <- (goal-was (act hold) (args ?name))
?thing <- (thing (name ?name) (loc ?place)

12. (on-top-of ceiling) (mass light weight))
(thing (name ladder) (loc ?place))
?Animal <- (Animal (loc ?place) (on-top-of ladder) (hold blank))
=>
(printout t "Animal grabs the " ?name "." crlf)
(modify ?thing (loc held) (on-top-of held))
(modify ?Animal (hold ?name))
(retract ?goal))
(defrule climb-to-hold ""
(goal-was (act hold) (args ?obj))
(thing (name ?obj) (loc ?place) (on-top-of ?on&~ceiling) (mass light weight))
(Animal (loc ?place) (on-top-of ~?on))
(not (goal-was (act on) (args ?on)))
=>
(assert (goal-was (act on) (args ?on))))
(defrule walk-to-hold ""
(goal-was (act hold) (args ?obj))
(thing (name ?obj) (loc ?place) (on-top-of ~ceiling) (mass light weight))
(Animal (loc ~?place))
(not (goal-was (act walk-to) (args ?place)))
=>
(assert (goal-was (act walk-to) (args ?place))))
(defrule drop-to-hold ""
(goal-was (act hold) (args ?obj))
(thing (name ?obj) (loc ?place) (on-top-of ?on) (mass light weight))
(Animal (loc ?place) (on-top-of ?on) (hold ~blank))
(not (goal-was (act hold) (args blank)))
=>
(assert (goal-was (act hold) (args blank))))
(defrule grab-object ""
?goal <- (goal-was (act hold) (args ?name))
?thing <- (thing (name ?name) (loc ?place)
(on-top-of ?on) (mass light weight))
?Animal <- (Animal (loc ?place) (on-top-of ?on) (hold blank))
=>
(printout t "Animal grabs the " ?name "." crlf)

13. (modify ?thing (loc held) (on-top-of held))
(modify ?Animal (hold ?name))
(retract ?goal))
(defrule drop-object ""
?goal <- (goal-was (act hold) (args blank))
?Animal <- (Animal (loc ?place)
(on-top-of ?on)
(hold ?name&~blank))
?thing <- (thing (name ?name))
=>
(printout t "Animal drops the " ?name "." crlf)
(modify ?Animal (hold blank))
(modify ?thing (loc ?place) (on-top-of ?on))
(retract ?goal))
;;;*********************
;;;* MOVE OBJECT RULES *
;;;*********************
(defrule unlock-chest-to-move-object ""
(goal-was (act move) (args ?obj ?))
(chest (name ?chest) (contents ?obj))
(not (goal-was (act unlock) (args ?chest)))
=>
(assert (goal-was (act unlock) (args ?chest))))
(defrule hold-object-to-move ""
(goal-was (act move) (args ?obj ?place))
(thing (name ?obj) (loc ~?place) (mass light weight))
(Animal (hold ~?obj))
(not (goal-was (act hold) (args ?obj)))
=>
(assert (goal-was (act hold) (args ?obj))))
(defrule move-object-to-place ""
(goal-was (act move) (args ?obj ?place))
(Animal (loc ~?place) (hold ?obj))
(not (goal-was (act walk-to) (args ?place)))
=>
(assert (goal-was (act walk-to) (args ?place))))

14. (defrule drop-object-once-moved ""
?goal <- (goal-was (act move) (args ?name ?place))
?Animal <- (Animal (loc ?place) (hold ?obj))
?thing <- (thing (name ?name) (mass light weight))
=>
(printout t "Animal drops the " ?name "." crlf)
(modify ?Animal (hold blank))
(modify ?thing (loc ?place) (on-top-of roof))
(retract ?goal))
(defrule already-moved-object ""
?goal <- (goal-was (act move) (args ?obj ?place))
(thing (name ?obj) (loc ?place))
=>
(retract ?goal))
;;;***********************
;;;* WALK TO PLACE RULES *
;;;***********************
(defrule already-at-place ""
?goal <- (goal-was (act walk-to) (args ?place))
(Animal (loc ?place))
=>
(retract ?goal))
(defrule get-on-roof-to-walk ""
(goal-was (act walk-to) (args ?place))
(Animal (loc ~?place) (on-top-of ~roof))
(not (goal-was (act on) (args roof)))
=>
(assert (goal-was (act on) (args roof))))
(defrule walk-hold-nothing ""
?goal <- (goal-was (act walk-to) (args ?place))
?Animal <- (Animal (loc ~?place) (on-top-of roof) (hold blank))
=>
(printout t "Animal walks to " ?place "." crlf)
(modify ?Animal (loc ?place))
(retract ?goal))
(defrule walk-hold-object ""

15. ?goal <- (goal-was (act walk-to) (args ?place))
?Animal <- (Animal (loc ~?place) (on-top-of roof) (hold ?obj&~blank))
=>
(printout t "Animal walks to " ?place " hold the " ?obj "." crlf)
(modify ?Animal (loc ?place))
(retract ?goal))
;;;***********************
;;;* GET ON OBJECT RULES *
;;;***********************
(defrule jump-onto-roof ""
?goal <- (goal-was (act on) (args roof))
?Animal <- (Animal (on-top-of ?on&~roof))
=>
(printout t "Animal jumps off the " ?on " onto the roof." crlf)
(modify ?Animal (on-top-of roof))
(retract ?goal))
(defrule walk-to-place-to-climb ""
(goal-was (act on) (args ?obj))
(thing (name ?obj) (loc ?place))
(Animal (loc ~?place))
(not (goal-was (act walk-to) (args ?place)))
=>
(assert (goal-was (act walk-to) (args ?place))))
(defrule drop-to-climb ""
(goal-was (act on) (args ?obj))
(thing (name ?obj) (loc ?place))
(Animal (loc ?place) (hold ~blank))
(not (goal-was (act hold) (args blank)))
=>
(assert (goal-was (act hold) (args blank))))
(defrule climb-indirectly ""
(goal-was (act on) (args ?obj))
(thing (name ?obj) (loc ?place) (on-top-of ?on))
(Animal (loc ?place) (on-top-of ~?on&~?obj) (hold blank))
(not (goal-was (act on) (args ?on)))
=>

16. (assert (goal-was (act on) (args ?on))))
(defrule climb-directly ""
?goal <- (goal-was (act on) (args ?obj))
(thing (name ?obj) (loc ?place) (on-top-of ?on))
?Animal <- (Animal (loc ?place) (on-top-of ?on) (hold blank))
=>
(printout t "Animal climbs onto the " ?obj "." crlf)
(modify ?Animal (on-top-of ?obj))
(retract ?goal))
(defrule already-on-object ""
?goal <- (goal-was (act on) (args ?obj))
(Animal (on-top-of ?obj))
=>
(retract ?goal))
;;;********************
;;;* EAT OBJECT RULES *
;;;********************
(defrule hold-to-eat ""
(goal-was (act eat) (args ?obj))
(Animal (hold ~?obj))
(not (goal-was (act hold) (args ?obj)))
=>
(assert (goal-was (act hold) (args ?obj))))
(defrule satisfy-hunger ""
?goal <- (goal-was (act eat) (args ?name))
?Animal <- (Animal (hold ?name))
?thing <- (thing (name ?name))
=>
(printout t "Animal eats the " ?name "." crlf)
(modify ?Animal (hold blank))
(retract ?goal ?thing))
;;;**********************
;;;* INITIAL STATE *
;;;**********************
(deffacts startup ""
(Animal (loc t5-7) (on-top-of greencouch) (hold blank))

17. (thing (name greencouch) (loc t5-7) (mass heavy))
(thing (name red-couch) (loc t2-2) (mass heavy))
(thing (name big-pillow) (loc t2-2) (on-top-of red-couch))
(thing (name red-chest) (loc t2-2) (on-top-of big-pillow))
(chest (name red-chest) (contents ladder) (unlocked-by red-key))
(thing (name blue-chest) (loc t7-7) (on-top-of ceiling))
(chest (name blue-chest) (contents bananas) (unlocked-by blue-key))
(thing (name blue-couch) (loc t8-8) (mass heavy))
(thing (name green-chest) (loc t8-8) (on-top-of ceiling))
(chest (name green-chest) (contents blue-key) (unlocked-by red-key))
(thing (name red-key) (loc t1-3))
(goal-was (act eat) (args bananas)))