codesamples/Prolog/wk3.pl

sentence(sentence(NP, VP)) --> np(Num, NP), vp(Num, _, VP).
np(Num, np(D, N)) --> det(D), noun(Num, N).
np(Num, np(D, N, Rel)) --> det(D), noun(Num, N), relcl(Num, Rel).
np(Num, np(D, A, N)) --> det(D), adj(A), noun(Num, N).
np(Num, np(D, A, N, Rel)) --> det(D), adj(A), noun(Num, N), relcl(Num, Rel).
np(Num, np(N)) --> noun(Num, N).
np(Num, np(N, Rel)) --> noun(Num, N), relcl(Num, Rel).
relcl(_, rel(R, NP, VP)) --> rel(obj, R), np(Num, NP), vp(Num, _, VP, obj).
relcl(Num, rel(R, VP)) --> rel(subj, R), vp(Num, _, VP, subj).
vp(Num, be, vp(V, A)) --> verb(Num, be, V), adj(A).
vp(Num, tr, vp(V, NP)) --> verb(Num, tr, V), np(_, NP).
vp(Num, intr, vp(V)) --> verb(Num, intr, V).
vp(Num, tr, vp(V), obj) --> verb(Num, tr, V).
vp(Num, tr, vp(V, NP), subj) --> verb(Num, tr, V), np(_, NP).
vp(Num, intr, vp(V), subj) --> verb(Num, intr, V).
vp(Num, be, vp(V, A), subj) --> verb(Num, be, V), adj(A).

det(det(D)) --> [D], {is_det(D)}.
noun(Num, noun(N)) --> [N], {is_noun(Num, N)}.
rel(Obj, rel(Rel)) --> [Rel], {is_rel(Obj, Rel)}.
verb(Num, Tr, verb(V)) --> [V], {is_verb(Num, Tr, V)}.
adj(adj(A)) --> [A], {is_adj(A)}.

is_noun(sg, apple).
is_noun(sg, boy).
is_noun(sg, girl).
is_noun(sg, government).
is_noun(sg, watermelon).
is_noun(sg, flavor).
is_noun(sg, person).
is_noun(pl, people).
is_noun(pl, Np) :- is_noun(sg, N), atom_chars(N, A), atom_chars(Np, B), append(A, [s], B).

is_det(a).
is_det(an).
is_det(the).
is_det(all).
is_det(some).

is_verb(pl, tr, conscript).
is_verb(pl, tr, eat).
is_verb(pl, tr, like).
is_verb(pl, intr, run).
is_verb(sg, be, is).
is_verb(pl, be, are).
is_verb(pl, tr, contain).
is_verb(sg, Tr, Vs) :- is_verb(pl, Tr, V), atom_chars(V, A), atom_chars(Vs, B), append(A, [s], B).

is_adj(evil).
is_adj(divine).
is_adj(big).
is_adj(tasty).
is_adj(pacifist).

is_rel(obj, that).
is_rel(obj, whom).
is_rel(subj, who).
is_rel(subj, which).


?- op(500,xfy,&).
?- op(600,xfy,=>).


np(Var, np(DET, NOUN), P3) :-
	n(Var, NOUN, P1),
	det(Var, DET, P1, P3).
np(Var,np(DET,ADJ,NOUN),P3) :-
	adj(Var,ADJ,P1),
	n(Var,NOUN,P2),
	det(Var,DET,P1,P2,P3).
np(Var, np(DET, NOUN, REL), P3) :-
	n(Var, NOUN, P1),
	det(Var, DET, P1, P2),
	rel(Var, REL, P2, P3).
np(Var, np(DET, ADJ, NOUN, REL), P4) :-
	n(Var, NOUN, P2),
	adj(Var, ADJ, P1),
	det(Var, DET, P1, P2, P3),
	rel(Var, REL, P3, P4).

det(Var,DET,P1,P2,P3) :- % noun-adj, universal
	DET =.. [det, all],
	P3 =.. [all, Var, (P2 & P1)].
det(Var, DET, P1, P2) :- % noun, universal
	DET =.. [det, all],
	P2 =.. [all, Var, P1].
det(Var, DET, P1, P2, P3) :- % noun-adj, existential
	DET =.. [det, some],
	P3 =.. [exists, Var, (P2 & P1)].
det(Var, DET, P1, P2) :- % noun, existential
	DET =.. [det, some],
	P2 =.. [exists, Var, P1].

adj(Var,ADJ,P) :-
	ADJ =.. [adj, A],
	P =.. [A,Var].

n(Var,NOUN,P) :-
	NOUN =.. [noun, N],
	P =.. [N,Var].

rel(Var, rel(_, VP), DET, P3) :-
	vp(Var, DET, VP, true, P3).


vp(Var, all(A, B), vp(BE, ADJ), P3) :- % 'to be' verb w/ adj
	BE =.. [verb, BB],
	is_verb(_, be, BB),
	adj(Var, ADJ, C),
	P3 =.. [all, A, (B => C)].
vp(Var, all(A, B), vp(VERB), P3) :- % intransitive verb
	VERB =..[verb, V],
	C =.. [V, Var],
	P3 =.. [all, A, (B => C)].
vp(Var, all(A, B), vp(VERB, NP), P3) :- % transitive verb w/ object
	VERB =.. [verb, V],
	gensym(x, Var2),
	np(Var2, NP, C),
	D =.. [V, Var, C],
	P3 =.. [all, A, (B => D)].

vp(Var, exists(A, B), vp(BE, ADJ), P3) :-
	BE =.. [verb, BB],
	is_verb(_, be, BB),
	adj(Var, ADJ, C),
	P3 =.. [exists, A, B, C].
vp(Var, exists(A, B), vp(VERB), P3) :-
	VERB =.. [verb, V],
	C =.. [V, Var],
	P3 =.. [exists, A, B, C].
vp(Var, exists(A, B), vp(VERB, NP), P3) :-
	VERB =.. [verb, V],
	gensym(x, Var2),
	np(Var2, NP, C),
	D =.. [V, Var, C],
	P3 =.. [exists, A, B, D].

vp(Var, all(A, B), vp(BE, ADJ), true, P3) :- % 'to be' verb w/ adj
	BE =.. [verb, BB],
	is_verb(_, be, BB),
	adj(Var, ADJ, C),
	P3 =.. [all, A, (B & C)].
vp(Var, all(A, B), vp(VERB), true, P3) :- % intransitive verb
	VERB =..[verb, V],
	C =.. [V, Var],
	P3 =.. [all, A, (B & C)].
vp(Var, all(A, B), vp(VERB, NP), true, P3) :- % transitive verb w/ object
	VERB =.. [verb, V],
	gensym(x, Var2),
	np(Var2, NP, C),
	D =.. [V, Var, C],
	P3 =.. [all, A, (B & D)].
vp(Var, exists(A, B), VP, true, P3) :-
	vp(Var, exists(A, B), VP, P3). 


s(sentence(NP,VP),F) :-
	gensym(x,X),
	np(X,NP,T), vp(X,T,VP,F).

prlogic(English, Logic) :- sentence(T, English, []), s(T, Logic).