% File:		sample3
% Author:	Peter Ross nicked it from GDR
% Updated:	3 June 1985

% ============ SAMPLE GRAMMAR ============

initial_category(trial,s).
strategy(trial,S) :-
	prompt(_,'Strategy (td/bu): '),
	read(S),
	member(S,[td,bu]),
	!.
strategy(trial,S) :-
	write('Answer  td.  or  bu.  please'), nl,
	strategy(trial,S).
policy(trial,P) :-
	prompt(_,'Policy (bf/df):   '),
	read(P),
	member(P,[bf,df]),
	!.
policy(trial,P) :-
	write('Answer  df.  or  bf.  please'), nl,
	policy(trial,P).

rule(trial, s,  [np, vp]).
rule(trial, np, [det, n]).
rule(trial, np, [np, pp]).
rule(trial, vp, [v]).
rule(trial, vp, [v, np]).
rule(trial, vp, [v, np, pp]).
rule(trial, pp, [p, np]).

lexical(trial, the,       [det]).
lexical(trial, a,         [det]).
lexical(trial, man,       [n,v]).
lexical(trial, women,     [n]).
lexical(trial, park,      [n]).
lexical(trial, telescope, [n]).
lexical(trial, in,        [p]).
lexical(trial, with,      [p]).
lexical(trial, saw,       [n,v]).
lexical(trial, likes,     [v]).