:- module(_,_,[]).

% A first program: the pets database.

pet(X) :-
    animal(X),
    barks(X).
pet(X) :-
    animal(X),
    meows(X).

animal(tim).
animal(spot).
animal(hobbes).

barks(spot).

meows(tim).

roars(hobbes).

%  Some examples of queries. Copy on the right, hit 
%  ENTER to execute, and then ; for other solutions.
%  ?- pet(spot).
%  ?- pet(X).