lib/a_star: intro `find_closest`

Signed-off-by: Alexis Laferrière <alexis.laf@xymus.net>

diff --git a/lib/a_star.nit b/lib/a_star.nit
index 7b7ce02..cc0cba3 100644 (file)
--- a/lib/a_star.nit
+++ b/lib/a_star.nit
@@ -188,6 +188,14 @@ class Node
                end
        end
 
+       # Find the closest node accepted by `cond` under `max_cost`
+       fun find_closest(max_cost: Int, context: PathContext, cond: nullable TargetCondition[N]): nullable N
+       do
+               var path = path_to_alts(null, max_cost, context, cond)
+               if path == null then return null
+               return path.nodes.last
+       end
+
        # We customize the serialization process to avoid problems with recursive
        # serialization engines. These engines, such as `JsonSerializer`,
        # are at danger to serialize the graph as a very deep tree.