X-Git-Url: http://nitlanguage.org

diff --git a/lib/a_star.nit b/lib/a_star.nit
index 9735d90..9ea68e8 100644
--- a/lib/a_star.nit
+++ b/lib/a_star.nit
@@ -14,9 +14,9 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-# Services related to pathfinding of graphs using A*
-# A single graph may have different properties according to the `PathContext` used
+# A* pathfinding in graphs
 #
+# A single graph may have different properties according to the `PathContext` used
 #
 # Usage:
 #
@@ -55,8 +55,12 @@
 # ~~~
 module a_star
 
+import serialization
+
 # General graph node
 class Node
+	super Serializable
+
 	# Type of the others nodes in the `graph`
 	type N: Node
 
@@ -86,7 +90,7 @@ class Node
 	# lifetime limited to evocation of `path_to`
 	private var open: Bool = false
 
-	# Main functionnality, returns path from `self` to `dest`
+	# Main functionality, returns path from `self` to `dest`
 	fun path_to(dest: N, max_cost: Int, context: PathContext): nullable AStarPath[N]
 	do
 		return path_to_alts(dest, max_cost, context, null)
@@ -183,10 +187,40 @@ class Node
 			end
 		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.
+	# With a large graph it can cause a stack overflow.
+	#
+	# Instead, we serialize the nodes first and then the links.
+	redef fun core_serialize_to(serializer)
+	do
+		serializer.serialize_attribute("graph", graph)
+	end
+
+	redef init from_deserializer(deserializer)
+	do
+		deserializer.notify_of_creation self
+
+		var graph = deserializer.deserialize_attribute("graph", (new GetName[Graph[N, Link]]).to_s)
+		if not graph isa Graph[N, Link] then graph = new Graph[N, Link]
+		self.graph = graph
+	end
 end
 
 # Link between two nodes and associated to a graph
 class Link
+	serialize
+
 	# Type of the nodes in `graph`
 	type N: Node
 
@@ -210,11 +244,13 @@ end
 
 # General graph
 class Graph[N: Node, L: Link]
+	super Serializable
+
 	# Nodes in this graph
-	var nodes: Set[N] = new HashSet[N]
+	var nodes = new Set[N]
 
 	# Links in this graph
-	var links: Set[L] = new HashSet[L]
+	var links = new Set[L]
 
 	# Add a `node` to this graph
 	fun add_node(node: N): N
@@ -236,15 +272,39 @@ class Graph[N: Node, L: Link]
 
 	# Used to check if nodes have been searched in one pathfinding
 	private var pathfinding_current_evocation: Int = 0
+
+	redef fun core_serialize_to(serializer)
+	do
+		serializer.serialize_attribute("nodes", nodes)
+		serializer.serialize_attribute("links", links)
+	end
+
+	redef init from_deserializer(deserializer)
+	do
+		deserializer.notify_of_creation self
+
+		var nodes = deserializer.deserialize_attribute("nodes", (new GetName[Set[N]]).to_s)
+		if deserializer.deserialize_attribute_missing then
+			deserializer.errors.add new AttributeMissingError(self, "nodes")
+		end
+		if nodes isa Set[N] then self.nodes = nodes
+
+		var links = deserializer.deserialize_attribute("links", (new GetName[Set[L]]).to_s)
+		if deserializer.deserialize_attribute_missing then
+			deserializer.errors.add new AttributeMissingError(self, "links")
+		end
+		if links isa Set[L] then for link in links do add_link link
+	end
 end
 
 # Result from path finding and a walkable path
 class AStarPath[N]
+	serialize
 
-	# The total cost of this path
+	# Total cost of this path
 	var total_cost: Int
 
-	# The list of nodes composing this path
+	# Nodes composing this path
 	var nodes = new List[N]
 
 	private var at: Int = 0
@@ -268,7 +328,9 @@ class AStarPath[N]
 end
 
 # Context related to an evocation of pathfinding
-class PathContext
+abstract class PathContext
+	serialize
+
 	# Type of the nodes in `graph`
 	type N: Node
 
@@ -302,6 +364,7 @@ end
 # Warning: A* is not optimize for such a case
 class ConstantPathContext
 	super PathContext
+	serialize
 
 	redef fun worst_cost do return 1
 	redef fun cost(l) do return 1
@@ -313,6 +376,7 @@ end
 # A `PathContext` for graphs with `WeightedLink`
 class WeightedPathContext
 	super PathContext
+	serialize
 
 	redef type L: WeightedLink
 
@@ -328,7 +392,7 @@ class WeightedPathContext
 		self.worst_cost = worst_cost
 	end
 
-	redef var worst_cost: Int is noinit
+	redef var worst_cost is noinit
 
 	redef fun cost(l) do
 		return l.weight
@@ -341,13 +405,16 @@ end
 # A `Link` with a `weight`
 class WeightedLink
 	super Link
+	serialize
 
 	# The `weight`, or cost, of this link
 	var weight: Int
 end
 
 # Advanced path conditions with customizable accept states
-class TargetCondition[N: Node]
+abstract class TargetCondition[N: Node]
+	serialize
+
 	# Should the pathfinding accept `node` as a goal?
 	fun accept(node: N): Bool is abstract