Support custom actions for blackboard tracker.

src/Murder/Core/Dialogs/CharacterRuntime.cs

@@ -473,7 +473,7 @@ private bool DoActionsForActiveDialog(World? world, Entity? target)
                         }
                     }
 
-                    DoAction(actionEntity, tracker, action);
+                    DoAction(world, actionEntity, tracker, action);
                 }
 
                 // If an entity has been created, trigger it immediately.
@@ -517,7 +517,7 @@ private bool DoLineEvents(Entity? target, Line line)
             return true;
         }
 
-        private void DoAction(Entity? actionEntity, BlackboardTracker tracker, DialogAction action)
+        private void DoAction(World? world, Entity? actionEntity, BlackboardTracker tracker, DialogAction action)
         {
             if (action.ComponentValue is IComponent component)
             {
@@ -532,21 +532,31 @@ private void DoAction(Entity? actionEntity, BlackboardTracker tracker, DialogAct
             switch (fact.Kind)
             {
                 case FactKind.Bool:
-                    tracker.SetBool(fact.Blackboard, fact.Name, action.Kind, action.BoolValue!.Value);
+                    bool @bool = action.BoolValue!.Value;
+
+                    tracker.SetBool(fact.Blackboard, fact.Name, action.Kind, @bool);
+                    tracker.OnFieldModifiedByDialogue(world, fact.Blackboard, fact.Name, action.Kind, @bool);
                     break;
 
                 case FactKind.Int:
-                    tracker.SetInt(fact.Blackboard, fact.Name, action.Kind, action.IntValue!.Value);
+                    int @int = action.IntValue!.Value;
+
+                    tracker.SetInt(fact.Blackboard, fact.Name, action.Kind, @int);
+                    tracker.OnFieldModifiedByDialogue(world, fact.Blackboard, fact.Name, action.Kind, @int);
                     break;
 
                 case FactKind.Float:
-                    tracker.SetFloat(fact.Blackboard, fact.Name, action.Kind, action.FloatValue!.Value);
+                    float @float = action.FloatValue!.Value;
+
+                    tracker.SetFloat(fact.Blackboard, fact.Name, action.Kind, @float);
+                    tracker.OnFieldModifiedByDialogue(world, fact.Blackboard, fact.Name, action.Kind, @float);
                     break;
 
                 case FactKind.String:
                     tracker.SetString(fact.Blackboard, fact.Name, action.StrValue!);
                     break;
             }
+
         }
 
         /// <summary>

src/Murder/Data/Save/BlackboardTracker.cs

@@ -500,6 +500,15 @@ private T GetValue<T>(string name) where T : notnull
             // Implemented by third-party
         }
 
+        /// <summary>
+        /// This provides custom proessing when a field is modified because of a dialogue action.
+        /// This can do custom behaviors to post-process the field.
+        /// </summary>
+        public virtual void OnFieldModifiedByDialogue<T>(World? world, string? blackboardName, string fieldName, BlackboardActionKind kind, T value) where T : notnull
+        {
+            // Implemented by third-party
+        }
+
         /// <summary>
         /// Set a variable value that is not available in any blackboard.
         /// </summary>