s(Sentence, Tree, Sem) :-
s(Sentence, [], Tree, Sem).
s(S0, S, s(NP, VP), Quant) :-
np(S0, S1, NP, Subj^Ass^Quant),
vp(S1, S, VP, Subj^Ass).
np(S0, S, np(D, N), X^Ass^Quant) :-
d(S0, S1, D, X^Scope^Ass^Quant),
n(S1, S, N, X^Scope).
np(S0, S, np(Name), Sem) :-
name( S0, S, Name, Sem).
vp(S0, S, vp(V, NP), Subj^Quant) :-
v( S0, S1, V, Subj^Obj^Pred),
np( S1, S, NP, Obj^Pred^Quant).
vp(S0, S, vp(V), Sem) :-
v( S0, S, V, Sem).
vp(S0, S, vp(V, NP), X^Scope) :-
cop(S0, S1, V),
np( S1, S, NP, X^Ass^exists(X, Scope, Ass)).
n([N|S], S, n(N), Sem) :-
n_(N, Sem).
name([N| S], S, name(N), Sem) :-
name_(N, Sem).
v([V|S], S, v(V), Sem) :-
v_(V, Sem).
d([D|S], S, d(D), Sem) :-
d_(D, Sem).
cop([C|S], S, cop(C)) :-
cop_(C).
n_(book, X^book(X)).
n_(man, X^man(X)).
n_(woman, X^woman(X)).
v_(arrive, X^arrives(X)).
v_(arrived, X^arrives(X)).
v_(arrives, X^arrives(X)).
v_(like, X^Y^likes(X, Y)).
v_(likes, X^Y^likes(X, Y)).
v_(liked, X^Y^likes(X, Y)).
v_(love, X^Y^loves(X, Y)).
v_(loves, X^Y^loves(X, Y)).
v_(loved, X^Y^loves(X, Y)).
v_(reads, X^Y^reads(X, Y)).
v_(sing, X^sings(X)).
v_(sings, X^sings(X)).
cop_(is).
d_(a, X^Scope^Ass^exists(X, Scope, Ass)).
d_(every, X^Scope^Ass^all(X, Scope, Ass)).
d_(the, X^Scope^Ass^the(X, Scope, Ass)).
name_(jack, jack^Ass^Ass).
name_(john, john^Ass^Ass).
name_(mary, mary^Ass^Ass).
write_tree( T) :-
write_tree( T, true, []).
write_tree( T, Last, Indent) :-
append( Indent, [124, 45, 32], IndentNode),
write_indent(IndentNode),
T =.. [ Node| Leaves],
write( Node), nl,
indent_leaves( Indent, Last, IndentLeaves),
write_leaves( Leaves, IndentLeaves).
write_leaves( [], Indent).
write_leaves( [ L], Indent) :-
write_tree( L, true, Indent).
write_leaves( [ L1, L2| Ls], Indent) :-
write_tree( L1, false, Indent),
write_leaves( [ L2| Ls], Indent).
indent_leaves( Indent, true, IndentLeaves) :- !,
append( Indent, [ 32, 32, 32], IndentLeaves).
indent_leaves( Indent, false, IndentLeaves) :- !,
append( Indent, [ 124, 32, 32], IndentLeaves).
write_indent( []).
write_indent( [ C| Cs]) :-
put( C),
write_indent( Cs).
Back to example 15.1
declare(exists(X, Scope, Ass)) :- !,
marker(X),
assert(kb(Scope)),
declare(Ass),
!.
declare(all(X, ScopeX, exists(Y, ScopeY, Pred))) :- !,
marker(X, Y),
assert(kb(ScopeY :- ScopeX)),
assert(kb(Pred :- ScopeX)),
!.
declare(all(X, ScopeX, all(Y, ScopeY, Pred))) :- !,
assert(kb(Pred :- ScopeX, ScopeY)),
!.
declare(all(X, ScopeX, Pred)) :- !,
assert(kb(Pred :- ScopeX)).
declare(Pred) :- !,
assert(kb(Pred)),
!.
marker(X) :-
get_marker(M),
X = f(M).
marker(X, Y) :-
get_marker(M),
Y = f(M, X).
get_marker(X) :-
marker_(M),
!,
retract(marker_(M)),
M1 is M + 1,
assert(marker_(M1)),
X = M1.
get_marker(X) :-
assert(marker_(0)),
X = M1.
Back to example 15.2
solve(all(X, Scope, Ass)) :- !,
not (solve(Scope),
not solve(Ass)),
solve(Scope),
!.
solve(exists(X, Scope, Ass)) :- !,
solve(Scope),
solve(Ass), !.
solve(X) :-
kb(X :- Y),
solve(Y).
solve(X) :-
kb(X),
write(X),
nl.
Back to example 15.3
chat([D|S]) :-
do(D), !,
s(S, Tree, Sem),
solve(Sem).
chat([who, D|S]) :-
do(D), !,
np(S, S1, T1, Subj^Pred^Q),
v(S1, [], T2, Subj^Obj^Pred),
solve(Pred),
write(Obj), nl.
chat([who|S]) :- !,
vp(S, [], Tree, Subj^Pred),
solve(Pred),
write(Subj), nl.
chat( S) :-
s(S, Tree, Sem),
declare(Sem).
do(does).
do(did).
Back to example 15.4
