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

diff --git a/lib/poset.nit b/lib/poset.nit
index 3288e5c..767b27d 100644
--- a/lib/poset.nit
+++ b/lib/poset.nit
@@ -17,6 +17,8 @@
 # Pre order sets and partial order set (ie hierarchies)
 module poset
 
+import serialization
+
 # Pre-order set graph.
 # This class models an incremental pre-order graph where new nodes and edges can be added (but not removed).
 # Pre-order graph has two characteristics:
@@ -74,6 +76,8 @@ module poset
 class POSet[E]
 	super Collection[E]
 	super Comparator
+	super Cloneable
+	super Serializable
 
 	redef type COMPARED: E is fixed
 
@@ -253,7 +257,7 @@ class POSet[E]
 			ids[x] = ids.length
 		end
 		for x in elements.keys do
-			var xstr = x.to_s.escape_to_dot
+			var xstr = (x or else "null").to_s.escape_to_dot
 			var nx = "n{ids[x]}"
 			f.write "{nx}[label=\"{xstr}\"];\n"
 			var xe = self.elements[x]
@@ -308,7 +312,7 @@ class POSet[E]
 	# ~~~~
 	#
 	# Note that the linear extension is stable, unless a new node or a new edge is added.
-	redef fun compare(a, b: E): Int
+	redef fun compare(a, b)
 	do
 		var ae = self.elements[a]
 		var be = self.elements[b]
@@ -380,9 +384,129 @@ class POSet[E]
 		sort(lin)
 		return lin
 	end
+
+	redef fun clone do return sub(self)
+
+	# Return an induced sub-poset
+	#
+	# The elements of the result are those given in argument.
+	#
+	# ~~~
+	# var pos = new POSet[String]
+	# pos.add_chain(["A", "B", "C", "D", "E"])
+	# pos.add_chain(["A", "X", "C", "Y", "E"])
+	#
+	# var pos2 = pos.sub(["A", "B", "D", "Y", "E"])
+	# assert pos2.has_exactly(["A", "B", "D", "Y", "E"])
+	# ~~~
+	#
+	# The full relationship is preserved between the provided elements.
+	#
+	# ~~~
+	# for e1 in pos2 do for e2 in pos2 do
+	#    assert pos2.has_edge(e1, e2) == pos.has_edge(e1, e2)
+	# end
+	# ~~~
+	#
+	# Not that by definition, the direct relationship is the transitive
+	# reduction of the full reduction. Thus, the direct relationship of the
+	# sub-poset may not be included in the direct relationship of self because an
+	# indirect edge becomes a direct one if all the intermediates elements
+	# are absent in the sub-poset.
+	#
+	# ~~~
+	# assert pos.has_direct_edge("B", "D")  == false
+	# assert pos2.has_direct_edge("B", "D") == true
+	#
+	# assert pos2["B"].direct_greaters.has_exactly(["D", "Y"])
+	# ~~~
+	#
+	# If the `elements` contains all then the result is a clone of self.
+	#
+	# ~~~
+	# var pos3 = pos.sub(pos)
+	# assert pos3 == pos
+	# assert pos3 == pos.clone
+	# ~~~
+	fun sub(elements: Collection[E]): POSet[E]
+	do
+		var res = new POSet[E]
+		for e in self do
+			if not elements.has(e) then continue
+			res.add_node(e)
+		end
+		for e in res do
+			for f in self[e].greaters do
+				if not elements.has(f) then continue
+				res.add_edge(e, f)
+			end
+		end
+		return res
+	end
+
+	# Two posets are equal if they contain the same elements and edges.
+	#
+	# ~~~
+	# var pos1 = new POSet[String]
+	# pos1.add_chain(["A", "B", "C", "D", "E"])
+	# pos1.add_chain(["A", "X", "C", "Y", "E"])
+	#
+	# var pos2 = new POSet[Object]
+	# pos2.add_edge("Y", "E")
+	# pos2.add_chain(["A", "X", "C", "D", "E"])
+	# pos2.add_chain(["A", "B", "C", "Y"])
+	#
+	# assert pos1 == pos2
+	#
+	# pos1.add_edge("D", "Y")
+	# assert pos1 != pos2
+	#
+	# pos2.add_edge("D", "Y")
+	# assert pos1 == pos2
+	#
+	# pos1.add_node("Z")
+	# assert pos1 != pos2
+	# ~~~
+	redef fun ==(other) do
+		if not other isa POSet[nullable Object] then return false
+		if not self.elements.keys.has_exactly(other.elements.keys) then return false
+		for e, ee in elements do
+			if ee.direct_greaters != other[e].direct_greaters then return false
+		end
+		assert hash == other.hash
+		return true
+	end
+
+	redef fun hash
+	do
+		var res = 0
+		for e, ee in elements do
+			if e == null then continue
+			res += e.hash
+			res += ee.direct_greaters.length
+		end
+		return res
+	end
+
+	redef fun core_serialize_to(serializer)
+	do
+		# Optimize written data because this structure has duplicated data
+		# For example, serializing the class hierarchy of a simple program where E is String
+		# result is before: 200k, after: 56k.
+		serializer.serialize_attribute("elements", elements)
+	end
+
+	redef init from_deserializer(deserializer)
+	do
+		deserializer.notify_of_creation self
+		var elements = deserializer.deserialize_attribute("elements")
+		if elements isa HashMap[E, POSetElement[E]] then
+			self.elements = elements
+		end
+	end
 end
 
-# View of an objet in a poset
+# View of an object in a poset
 # This class is a helper to handle specific queries on a same object
 #
 # For instance, one common usage is to add a specific attribute for each poset a class belong.
@@ -397,6 +521,8 @@ end
 # t.in_some_relation.greaters
 # ~~~
 class POSetElement[E]
+	super Serializable
+
 	# The poset self belong to
 	var poset: POSet[E]
 
@@ -512,6 +638,175 @@ class POSetElement[E]
 			end
 		end
 		return min
+	end
+
+	redef fun core_serialize_to(serializer)
+	do
+		serializer.serialize_attribute("poset", poset)
+		serializer.serialize_attribute("element", element)
+		serializer.serialize_attribute("tos", tos)
+		serializer.serialize_attribute("froms", froms)
+		serializer.serialize_attribute("dtos", dtos)
+		serializer.serialize_attribute("dfroms", dfroms)
+		serializer.serialize_attribute("count", count)
+
+		# Don't serialize `froms`, `dtos` and `tos` as they duplicate information.
+		# TODO serialize them if a flag for extra info is set on `serializer`.
+	end
+
+	redef init from_deserializer(v)
+	do
+		# Code generated by the serialization_phase from the compiler frontend,
+		# copied here for compatibility with nith.
+
+		super
+		v.notify_of_creation self
+
+		var poset = v.deserialize_attribute("poset", "POSet[nullable Object]")
+		if v.deserialize_attribute_missing then
+			v.errors.add new Error("Deserialization Error: attribute `{class_name}::poset` missing from JSON object")
+		else if not poset isa POSet[E] then
+			v.errors.add new AttributeTypeError(self, "poset", poset, "POSet[nullable Object]")
+			if v.keep_going == false then return
+		else
+			self.poset = poset
+		end
 
+		var element = v.deserialize_attribute("element", "nullable Object")
+		if v.deserialize_attribute_missing then
+			v.errors.add new Error("Deserialization Error: attribute `{class_name}::element` missing from JSON object")
+		else if not element isa E then
+			v.errors.add new AttributeTypeError(self, "element", element, "nullable Object")
+			if v.keep_going == false then return
+		else
+			self.element = element
+		end
+
+		var tos = v.deserialize_attribute("tos", "HashSet[nullable Object]")
+		if v.deserialize_attribute_missing then
+		else if not tos isa HashSet[E] then
+			v.errors.add new AttributeTypeError(self, "tos", tos, "HashSet[nullable Object]")
+			if v.keep_going == false then return
+		else
+			self.tos = tos
+		end
+
+		var froms = v.deserialize_attribute("froms", "HashSet[nullable Object]")
+		if v.deserialize_attribute_missing then
+		else if not froms isa HashSet[E] then
+			v.errors.add new AttributeTypeError(self, "froms", froms, "HashSet[nullable Object]")
+			if v.keep_going == false then return
+		else
+			self.froms = froms
+		end
+
+		var dtos = v.deserialize_attribute("dtos", "HashSet[nullable Object]")
+		if v.deserialize_attribute_missing then
+		else if not dtos isa HashSet[E] then
+			v.errors.add new AttributeTypeError(self, "dtos", dtos, "HashSet[nullable Object]")
+			if v.keep_going == false then return
+		else
+			self.dtos = dtos
+		end
+
+		var dfroms = v.deserialize_attribute("dfroms", "HashSet[nullable Object]")
+		if v.deserialize_attribute_missing then
+		else if not dfroms isa HashSet[E] then
+			v.errors.add new AttributeTypeError(self, "dfroms", dfroms, "HashSet[nullable Object]")
+			if v.keep_going == false then return
+		else
+			self.dfroms = dfroms
+		end
+
+		var count = v.deserialize_attribute("count", "Int")
+		if v.deserialize_attribute_missing then
+			v.errors.add new Error("Deserialization Error: attribute `{class_name}::count` missing from JSON object")
+		else if not count isa Int then
+			v.errors.add new AttributeTypeError(self, "count", count, "Int")
+			if v.keep_going == false then return
+		else
+			self.count = count
+		end
+	end
+end
+
+redef class MapRead[K, V]
+	# Return all elements of `keys` that have a value.
+	#
+	# ~~~
+	# var map = new Map[String, String]
+	# map["A"] = "a"
+	# map["B"] = "b"
+	# map["C"] = "c"
+	#
+	# assert map.filter_keys(["B"]) == ["B"]
+	# assert map.filter_keys(["A", "Z", "C"]) == ["A", "C"]
+	# assert map.filter_keys(["X", "Y", "Z"]).is_empty
+	# ~~~
+	#
+	# `has_key` is used to filter.
+	fun filter_keys(keys: Collection[nullable Object]): Array[K]
+	do
+		var res = new Array[K]
+		for e in keys do
+			if has_key(e) then res.add e
+		end
+		return res
+	end
+
+	# Search all the values in `pe.greaters`.
+	#
+	# Elements without values are ignored.
+	#
+	# Basically, values defined in all greater elements of `pe` are inherited.
+	#
+	# ~~~
+	# var pos = new POSet[String]
+	# pos.add_chain(["E", "D", "C", "B", "A"])
+	# pos.add_chain(["D", "X", "B"])
+	#
+	# var map = new HashMap[String, String]
+	# map["A"] = "a"
+	# map["C"] = "c"
+	# map["X"] = "x"
+	# map["E"] = "e"
+	#
+	# assert map.lookup_all_values(pos["B"]).has_exactly(["a"])
+	# assert map.lookup_all_values(pos["C"]).has_exactly(["a", "c"])
+	# assert map.lookup_all_values(pos["D"]).has_exactly(["a", "c", "x"])
+	# ~~~
+	fun lookup_all_values(pe: POSetElement[K]): Set[V]
+	do
+		var res = new Set[V]
+		for k in filter_keys(pe.greaters) do res.add self[k]
+		return res
+	end
+
+	# Combine the values in `pe.greaters` from the most smaller elements that have a value.
+	#
+	# Elements without values are ignored.
+	#
+	# Basically, values defined in nearest greater elements of `pe` are inherited.
+	#
+	# ~~~
+	# var pos = new POSet[String]
+	# pos.add_chain(["E", "D", "C", "B", "A"])
+	# pos.add_chain(["D", "X", "B"])
+	#
+	# var map = new HashMap[String, String]
+	# map["A"] = "a"
+	# map["C"] = "c"
+	# map["X"] = "x"
+	# map["E"] = "e"
+	#
+	# assert map.lookup_values(pos["B"]).has_exactly(["a"])
+	# assert map.lookup_values(pos["C"]).has_exactly(["c"])
+	# assert map.lookup_values(pos["D"]).has_exactly(["c", "x"])
+	# ~~~
+	fun lookup_values(pe: POSetElement[K]): Set[V]
+	do
+		var res = new Set[V]
+		for k in pe.poset.select_smallest(filter_keys(pe.greaters)) do res.add self[k]
+		return res
 	end
 end