I kind of miss programming like this:
go :- hypothesize(Animal),
write('I guess that the animal is: '),
write(Animal),
nl,
undo.
hypothesize(cheetah) :- cheetah, !.
hypothesize(tiger) :- tiger, !.
hypothesize(giraffe) :- giraffe, !.
hypothesize(zebra) :- zebra, !.
hypothesize(ostrich) :- ostrich, !.
hypothesize(penguin) :- penguin, !.
hypothesize(albatross) :- albatross, !.
hypothesize(unknown).
cheetah :- mammal,
carnivore,
verify(has_tawny_color),
verify(has_dark_spots).
tiger :- mammal,
carnivore,
verify(has_tawny_color),
verify(has_black_stripes).
giraffe :- ungulate,
verify(has_long_neck),
verify(has_long_legs).
zebra :- ungulate,
verify(has_black_stripes).
ostrich :- bird,
verify(does_not_fly),
verify(has_long_neck).
penguin :- bird,
verify(does_not_fly),
verify(swims),
verify(is_black_and_white).
albatross :- bird,
verify(appears_in_story_Ancient_Mariner),
verify(flys_well).
mammal :- verify(has_hair), !.
mammal :- verify(gives_milk).
bird :- verify(has_feathers), !.
bird :- verify(flys),
verify(lays_eggs).
carnivore :- verify(eats_meat), !.
carnivore :- verify(has_pointed_teeth),
verify(has_claws),
verify(has_forward_eyes).
ungulate :- mammal,
verify(has_hooves), !.
ungulate :- mammal,
verify(chews_cud).
ask(Question) :-
write('Does the animal have the following attribute: '),
write(Question),
write('? '),
read(Response),
nl,
( (Response == yes ; Response == y)
->
assert(yes(Question)) ;
assert(no(Question)), fail).
:- dynamic yes/1,no/1.
verify(S) :-
(yes(S)
->
true ;
(no(S)
->
fail ;
ask(S))).
undo :- retract(yes(_)),fail.
undo :- retract(no(_)),fail.
undo.