;;;; -*- Mode: Lisp; Syntax: Common-Lisp; -*-
;;;; Code from Paradigms of AI Programming
;;;; Copyright (c) 1991 Peter Norvig

;;; begin grammar snippet

(rule (S (?pred ?subj)) -->
  (NP ?agr ?subj)
  (VP ?agr ?pred))

(rule (NP ?agr (?det ?n)) -->
  (Det ?agr ?det)
  (N ?agr ?n))

(rule (NP 3sg (the male))          --> (:word he))
(rule (NP ~3sg (some objects))     --> (:word they))
(rule (VP 3sg sleep)               --> (:word sleeps))
(rule (VP ~3sg sleep)              --> (:word sleep))
(rule (Det ?any the)               --> (:word the))
(rule (N 3sg (young male human))   --> (:word boy))
(rule (N 3sg (young female human)) --> (:word girl))

;;; end grammar snippet

;;; begin grammar snippet

(rule (S ?pred) -->
  (NP ?agr ?subj)
  (VP ?agr ?subj ?pred))

(rule (VP ?agr ?subj ?pred) -->
  (Verb/tr ?agr ?subj ?pred ?obj)
  (NP ?any-agr ?obj))

(rule (VP ?agr ?subj ?pred) -->
  (Verb/intr ?agr ?subj ?pred))

(rule (Verb/tr ~3sg ?x (kiss ?x ?y) ?y) --> (:word kiss))
(rule (Verb/tr 3sg ?x (kiss ?x ?y) ?y) --> (:word kisses))
(rule (Verb/tr ?any  ?x (kiss ?x ?y) ?y) --> (:word kissed))

(rule (Verb/intr ~3sg ?x (sleep ?x)) --> (:word sleep))
(rule (Verb/intr 3sg ?x (sleep ?x)) --> (:word sleeps))
(rule (Verb/intr ?any  ?x (sleep ?x)) --> (:word slept))

(rule (NP ?agr ?sem) -->
  (Name ?agr ?sem))

(rule (NP ?agr (?det-sem ?noun-sem)) -->
  (Det ?agr ?det-sem)
  (Noun ?agr ?noun-sem))

(rule (Name 3sg Terry) --> (:word Terry))
(rule (Name 3sg Jean)  --> (:word Jean))

(rule (Noun 3sg (young male human))           --> (:word boy))
(rule (Noun 3sg (young female human))         --> (:word girl))
(rule (Noun ~3sg (group (young male human)))   --> (:word boys))
(rule (Noun ~3sg (group (young female human))) --> (:word girls))

(rule (Det ?any the)  --> (:word the))
(rule (Det 3sg a) --> (:word a))

;;; end grammar snippet

;;; begin examples for last snippet

> (?- (S ?sem (The boys kiss a girl) ()))
?SEM = (KISS (THE (GROUP (YOUNG MALE HUMAN)))
             (A (YOUNG FEMALE HUMAN))).

> (?- (S ?sem (The girls kissed the girls) ()))
?SEM = (KISS (THE (GROUP (YOUNG FEMALE HUMAN)))
             (THE (GROUP (YOUNG FEMALE HUMAN)))).

> (?- (S ?sem (Terry kissed the girl) ()))
?SEM = (KISS TERRY (THE (YOUNG FEMALE HUMAN))).

> (?- (S ?sem (The girls kisses the boys) ()))
No.

> (?- (S ?sem (Terry kissed a girls) ()))
No.

> (?- (S ?sem (Terry sleeps Jean) ()))
No.

;;; end examples

;;; begin grammar snippet

(rule (Det ?any ?x ?p ?q (the ?x (and ?p ?q)))    --> (:word the))
(rule (Det 3sg  ?x ?p ?q (exists ?x (and ?p ?q))) --> (:word a))
(rule (Det 3sg  ?x ?p ?q (all    ?x (-> ?p ?q)))  --> (:word every))

(rule (Noun 3sg ?x (picture ?x)) --> (:word picture))
(rule (Noun 3sg ?x (story ?x)) --> (:word story))
(rule (Noun 3sg ?x (and (young ?x) (male ?x) (human ?x))) -->
  (:word boy))

(rule (NP ?agr ?x ?pred ?pred) -->
  (Name ?agr ?name))

;(rule (NP ?agr ?x ?pred ?np) -->
;  (Det ?agr ?x ?noun ?pred ?np)
;  (Noun ?agr ?x ?noun))

(rule (NP ?agr ?x ?pred ?np) -->
  (Det ?agr ?x ?noun&rel ?pred ?np)
  (Noun ?agr ?x ?noun)
  (rel-clause ?agr ?x ?noun ?noun&rel))

(rule (rel-clause ?agr ?x ?np ?np) --> )
(rule (rel-clause ?agr ?x ?np (and ?np ?rel)) -->
  (:word that)
  (VP ?agr ?x ?rel))

(rule (Verb/tr ~3sg ?x ?y (paint ?x ?y)) --> (:word paint))
(rule (Verb/tr 3sg  ?x ?y (paint ?x ?y)) --> (:word paints))
(rule (Verb/tr ?any ?x ?y (paint ?x ?y)) --> (:word painted))

(rule (Verb/intr ~3sg ?x (sleep ?x)) --> (:word sleep))
(rule (Verb/intr 3sg  ?x (sleep ?x)) --> (:word sleeps))
(rule (Verb/intr ?any ?x (sleep ?x)) --> (:word slept))

(rule (Verb/intr 3sg  ?x (sells ?x)) --> (:word sells))
(rule (Verb/intr 3sg  ?x (stinks ?x)) --> (:word stinks))

(rule (VP ?agr ?x ?vp) -->
  (Verb/tr ?agr ?x ?obj ?verb)
  (NP ?any-agr ?obj ?verb ?vp))

(rule (VP ?agr ?x ?vp) -->
  (Verb/intr ?agr ?x ?vp))

(rule (S ?np) -->
  (NP ?agr ?x ?vp ?np)
  (VP ?agr ?x ?vp))

;;; end grammar snippet

;;; begin examples for last snippet

Every picture paints a story.
(ALL ?3 (-> (PICTURE ?3)
            (EXISTS ?14 (AND (STORY ?14) (PAINT ?3 ?14)))))

Every boy that paints a picture sleeps.
(ALL ?3 (-> (AND (AND (YOUNG ?3) (MALE ?3) (HUMAN ?3))
                 (EXISTS ?19 (AND (PICTURE ?19)
                                  (PAINT ?3 ?19))))
            (SLEEP ?3)))

Every boy that sleeps paints a picture.
(ALL ?3 (-> (AND (AND (YOUNG ?3) (MALE ?3) (HUMAN ?3))
                 (SLEEP ?3))
            (EXISTS ?22 (AND (PICTURE ?22) (PAINT ?3 ?22)))))

Every boy that paints a picture that sells 
paints a picture that stinks.
(ALL ?3 (-> (AND (AND (YOUNG ?3) (MALE ?3) (HUMAN ?3))
                 (EXISTS ?19 (AND (AND (PICTURE ?19) (SELLS ?19))
                                  (PAINT ?3 ?19))))
            (EXISTS ?39 (AND (AND (PICTURE ?39) (STINKS ?39))
                             (PAINT ?3 ?39)))))

;;; end examples

;;; begin grammar snippet

(rule (S (and ?np ?vp)) -->
  (NP ?agr ?x ?np)
  (VP ?agr ?x ?vp))

(rule (VP ?agr ?x (and ?verb ?obj)) -->
  (Verb/tr ?agr ?x ?o ?verb)
  (NP ?any-agr ?o ?obj))

(rule (VP ?agr ?x ?verb) -->
  (Verb/intr ?agr ?x ?verb))

(rule (NP ?agr ?name t) -->
  (Name ?agr ?name))

(rule (NP ?agr ?x ?det) -->
  (Det ?agr ?x (and ?noun ?rel) ?det)
  (Noun ?agr ?x ?noun)
  (rel-clause ?agr ?x ?rel))

(rule (rel-clause ?agr ?x t) --> )
(rule (rel-clause ?agr ?x ?rel) -->
  (:word that)
  (VP ?agr ?x ?rel))

(rule (Name 3sg Terry)                     --> (:word Terry))
(rule (Name 3sg Jean)                      --> (:word Jean))
(rule (Det 3sg  ?x ?restr (all ?x ?restr)) --> (:word every))
(rule (Noun 3sg ?x (man ?x))               --> (:word man))
(rule (Verb/tr 3sg ?x ?y (love ?x ?y))     --> (:word loves))
(rule (Verb/intr 3sg ?x (lives ?x))        --> (:word lives))
(rule (Det 3sg  ?x ?res (exists ?x ?res))  --> (:word a))
(rule (Noun 3sg ?x (woman ?x))             --> (:word woman))

;;; end grammar snippet

;;; begin examples for last snippet

(and (all ?4 (and (man ?4) t))
     (and (love ?4 ?12) (exists ?12 (and (woman ?12) t)))) 

;;; ==============================

(and (all ?m (man ?m))
     (exists ?w (wowan ?w))
     (loves ?m ?w))

;;; end examples

;;; begin grammar snippet

(rule (S ?g0 ?g2 (and ?np ?vp)) -->
  (NP ?g0 ?g1 ?agr ?x ?np)
  (VP ?g1 ?g2 ?agr ?x ?vp))

(rule (VP ?g0 ?g1 ?agr ?x (and ?obj ?verb)) -->
  (Verb/tr ?agr ?x ?o ?verb)
  (NP ?g0 ?g1 ?any-agr ?o ?obj))

(rule (VP ?g0 ?g0 ?agr ?x ?verb) -->
  (Verb/intr ?agr ?x ?verb))

(rule (NP ?g0 ?g0 ?agr ?name t) -->
  (Name ?agr ?name))

(rule (NP ?g0 ?g0 ?agr ?x ?det) -->
  (Det ?agr ?x (and ?noun ?rel) ?det)
  (Noun ?agr ?x ?noun)
  (rel-clause ?agr ?x ?rel))

(rule (NP (gap NP ?agr ?x) nogap ?agr ?x t) --> )

(rule (rel-clause ?agr ?x t) --> )

(rule (rel-clause ?agr ?x ?rel) -->
  (:word that)
  (S (gap NP ?agr ?x) nogap ?rel))

;;; end grammar snippet

;;; begin examples for last snippet

Every man that __ loves a woman likes a person.
(AND (ALL ?28 (AND (MAN ?28)
                   (AND T (AND (LOVE ?28 ?30)
                               (EXISTS ?30 (AND (WOMAN ?30)
                                                T))))))
     (AND (EXISTS ?39 (AND (PERSON ?39) T)) (LIKE ?28 ?39)))

Every man that a woman loves __ likes a person.
(AND (ALL ?37 (AND (MAN ?37)
                   (AND (EXISTS ?20 (AND (WOMAN ?20) T))
                        (AND T (LOVE ?20 ?37)))))
     (AND (EXISTS ?39 (AND (PERSON ?39) T)) (LIKE ?37 ?39)))

Every man that loves a bird that __ flies likes a person.
(AND (ALL ?28 (AND (MAN ?28)
                   (AND T (AND (EXISTS ?54
                                  (AND (BIRD ?54)
                                       (AND T (FLY ?54))))
                               (LOVE ?28 ?54)))))
     (AND (EXISTS ?60 (AND (PERSON ?60) T)) (LIKE ?28 ?60)))

;;; end examples