Depth First Search
Here is simple code for depth first search. It is taken from the book
of Ivan Bratko.
<![CDATA[
% solve(+Start,-Solution)
% Solution is an acyclic path (in reverse order)
% from Start to a goal
%
solve(Start, Solution) :-
depthfirst([], Start, Solution).
% depthfirst(+Path, +Node, -Solution).
% Path is the path to Node from start.
%
% Node is it.
depthfirst(Path, Node, [Node|Path]) :-
goal(Node). % you have to write goal(+Node).
depthfirst(Path, Node, Solution) :-
successor(Node, Node1), % go to a new node
\+ member(Node1, Path), % but don't go backwards!
depthfirst([Node|Path], Node1, Solution).
]]>
Note.
For more details on (\+)/2. This is a form of " not ".
It must be used with care.
Jonathan Hodgson
Last Changed: 1999/10/07