Implemented some enhancement request and fixed some bugs

Fixed #2 : Variables are not recognized when inside a rule token
Fixed #15 : Rule: rete attributes are lost when a new ontology is created
Fixed #14 : ReteNetwork: Format rules must not be added to Rete network
Fixed #16 : DefConcept: Variables are not recognized when they are keyword arguments
Fixed #4 : Comparison are not correctly set when comparison property is a concept
Fixed #14 : Parser: merge FunctionParser.NamesNode and ExpressionParser.NamesNode
Fixed #18 : Parser: Add SourceCodeNode test to UnrecognizedNodeParser
Fixed #20 : At startup Number concept is saved in db a numerous number of time
Fixed #21 : CacheManager: I can remove all elements from a ListIfNeededCache and fill it again
Fixed #22 : CacheManager: I can remove all elements from a SetCache and fill it again
Fixed #23 : HistoryManager: history() no longer works
Fixed #24 : HistoryManager: history() no longer works after creating an exec rule
Fixed #25 : SheerkaMemory: Use MemoryObject instead of sheerka.local
Fixed #26 : Debugger: add the list all available services..
Fixed #27 : CONCEPTS_GRAMMARS_ENTRY does not seems to be in use any more
Fixed #28 : Give order to services

tests/core/test_SheerkaMemory.py

@@ -88,7 +88,6 @@ class TestSheerkaMemory(TestUsingMemoryBasedSheerka):
         assert sheerka.om.copy(SheerkaMemory.OBJECTS_ENTRY) == {"a": MemoryObject(context.event.get_digest(), foo)}
         assert id(sheerka.get_from_memory(context, "a").obj) == id(foo)
 
-
     def test_i_can_use_memory_with_a_string(self):
         sheerka, context = self.init_test().unpack()
 
@@ -129,6 +128,69 @@ class TestSheerkaMemory(TestUsingMemoryBasedSheerka):
 
         assert len(sheerka.om.get_all(SheerkaMemory.OBJECTS_ENTRY)) == 0
 
+    def test_adding_the_same_object_with_same_context_has_no_effect_when_one_element(self):
+        sheerka, context, foo = self.init_concepts("foo")
+        service = sheerka.services[SheerkaMemory.NAME]
+
+        sheerka.add_to_memory(context, "item", foo)
+        from_memory = service.get_from_memory(context, "item")
+
+        sheerka.add_to_memory(context, "item", foo)
+        from_memory_again = service.get_from_memory(context, "item")
+        assert from_memory_again == from_memory
+
+    def test_adding_the_same_object_with_same_context_has_no_effect_when_multiple_elements(self):
+        sheerka, context, foo, bar, baz = self.init_concepts("foo", "bar", "baz")
+        service = sheerka.services[SheerkaMemory.NAME]
+
+        sheerka.add_to_memory(context, "item", foo)
+        sheerka.add_to_memory(context, "item", bar)
+        sheerka.add_to_memory(context, "item", baz)
+        from_memory = service.get_from_memory(context, "item").copy()
+
+        sheerka.add_to_memory(context, "item", baz)
+        from_memory_again = service.get_from_memory(context, "item")
+        assert from_memory_again == from_memory
+
+    def test_adding_the_same_object_with_a_different_context_updates_event_id_when_one_element(self):
+        sheerka, context1, foo = self.init_concepts("foo")
+        service = sheerka.services[SheerkaMemory.NAME]
+
+        sheerka.add_to_memory(context1, "item", foo)
+        from_memory = service.get_from_memory(context1, "item")
+
+        context2 = self.get_context(self.sheerka, message="another message")
+        sheerka.add_to_memory(context2, "item", foo)
+        from_memory_again = service.get_from_memory(context2, "item")
+
+        assert from_memory_again != from_memory
+        assert not isinstance(from_memory_again, list)
+
+        assert from_memory_again.obj == from_memory.obj
+        assert from_memory_again.event_id == context2.event.get_digest()
+        assert from_memory.event_id == context1.event.get_digest()
+
+    def test_adding_the_same_object_with_a_different_context_updates_event_id_when_multiple_elements(self):
+        sheerka, context, foo, bar, baz = self.init_concepts("foo", "bar", "baz")
+        service = sheerka.services[SheerkaMemory.NAME]
+
+        sheerka.add_to_memory(context, "item", foo)
+        sheerka.add_to_memory(context, "item", bar)
+        sheerka.add_to_memory(context, "item", baz)
+        from_memory = service.get_from_memory(context, "item").copy()
+
+        context2 = self.get_context(self.sheerka, message="another message")
+        sheerka.add_to_memory(context2, "item", baz)
+        from_memory_again = service.get_from_memory(context2, "item")
+
+        assert isinstance(from_memory_again, list)
+        assert len(from_memory) == len(from_memory_again)
+        for mo, mo_again in zip(from_memory, from_memory_again[:-1]):
+            assert mo == mo_again
+
+        assert from_memory[-1].obj == from_memory_again[-1].obj
+        assert from_memory[-1].event_id != from_memory_again[-1].event_id
+
 
 class TestSheerkaMemoryUsingFileBase(TestUsingFileBasedSheerka):
     def test_i_can_record_memory_objects(self):