:- object(depth_first(Bound),
instantiates(blind_search(Bound))).
:- info([
version is 1.0,
author is 'Paulo Moura',
date is 1998/3/23,
comment is 'Depth first state space search strategy.',
parnames is ['Bound']]).
:- uses(list).
search(Space, State, Bound, Solution) :-
depth(Space, State, Bound, [], Path),
list::reverse(Path, Solution).
depth(Space, State, _, Path, [State| Path]) :-
Space::goal_state(State).
depth(Space, State, Bound, Path, Solution) :-
Bound > 0,
Space::next_state(State, Next),
\+ list::member(Next, [State| Path]),
Bound2 is Bound - 1,
depth(Space, Next, Bound2, [State| Path], Solution).
:- end_object.
