Fix sequence init (#108)

Author: jaagut

dynamic_stack_decider/CMakeLists.txt

@@ -201,13 +201,10 @@ def _bind_modules(self, element):
         else:
             raise ValueError(f'Unknown parser tree element type "{type(element)}" for element "{element}"!')
 
-    def _init_element(self, element: AbstractTreeElement):
+    def _init_element(self, element: AbstractTreeElement) -> AbstractStackElement:
         """Initializes the module belonging to the given element."""
         if isinstance(element, SequenceTreeElement):
-            initialized_actions = list()
-            for action in element.action_elements:
-                initialized_actions.append(action.module(self.blackboard, self, action.parameters))
-            return SequenceElement(self.blackboard, self, initialized_actions)
+            return SequenceElement(self.blackboard, self, element.action_elements, self._init_element)
         else:
             return element.module(self.blackboard, self, element.parameters)
 

dynamic_stack_decider/dynamic_stack_decider/dsd.py

@@ -1,7 +1,8 @@
-from typing import TYPE_CHECKING
+from typing import TYPE_CHECKING, Callable
 
 from dynamic_stack_decider.abstract_action_element import AbstractActionElement
 from dynamic_stack_decider.abstract_stack_element import AbstractStackElement
+from dynamic_stack_decider.tree import AbstractTreeElement, ActionTreeElement
 
 if TYPE_CHECKING:
     from dynamic_stack_decider.dsd import DSD
@@ -16,21 +17,44 @@ class SequenceElement(AbstractStackElement):
     This is not an abstract class to inherit from.
     """
 
-    def __init__(self, blackboard, dsd: "DSD", actions: list[AbstractActionElement]):
+    def __init__(
+        self,
+        blackboard,
+        dsd: "DSD",
+        actions: list[ActionTreeElement],
+        init_function: Callable[[AbstractTreeElement], AbstractStackElement],
+    ):
         """
-        :param actions: list of initialized action elements
+        :param blackboard: Shared blackboard for data exchange and code reuse between elements
+        :param dsd: The stack decider which has this element on its stack.
+        :param actions: list of of action tree elements / blueprints for the actions
+        :param init_function: A function that initializes an action element creating a stack element from a tree element
         """
         super().__init__(blackboard, dsd, dict())
+        # Here we store the 'blueprints' of the actions
         self.actions = actions
-        self.current_action_index = 0
+        # We store a reference to the function that initializes the action elements based on the tree
+        self._init_function = init_function
+        # Here we store the actual instances of the active action
+        # The action is only initialized when it is the current action
+        assert len(actions) > 0, "A sequence element must contain at least one action"
+        self.current_action: AbstractActionElement = self._init_function(actions[0])
+        # Where we are in the sequence
+        self.current_action_index: int = 0
 
     def perform(self, reevaluate=False):
         """
         Perform the current action of the sequence. See AbstractStackElement.perform() for more information
 
         :param reevaluate: Ignored for SequenceElements
         """
+        # Log the active element
+        self.publish_debug_data("Active Element", self.current_action.name)
+        # Pass the perform call to the current action
         self.current_action.perform()
+        # If the action had debug data, publish it
+        if self.current_action._debug_data:
+            self.publish_debug_data("Corresponding debug data", self.current_action._debug_data)
 
     def pop_one(self):
         """
@@ -39,30 +63,24 @@ def pop_one(self):
         assert not self.in_last_element(), (
             "It is not possible to pop a single element when" "the last element of the sequence is active"
         )
+        # Increment the index to the next action and initialize it
         self.current_action_index += 1
+        # We initilize the current action here to avoid the problem described in
+        # https://github.com/bit-bots/dynamic_stack_decider/issues/107
+        self.current_action = self._init_function(self.actions[self.current_action_index])
 
     def in_last_element(self):
         """Returns if the current element is the last element of the sequence"""
         return self.current_action_index == len(self.actions) - 1
 
-    @property
-    def current_action(self) -> AbstractActionElement:
-        """
-        Returns the currently executed action of the sequence element
-        """
-        return self.actions[self.current_action_index]
-
     def repr_dict(self) -> dict:
         """
         Represent this stack element as dictionary which is JSON encodable
         """
-        self.publish_debug_data("Active Element", self.current_action.name)
-        if self.current_action._debug_data:
-            self.publish_debug_data("Corresponding debug data", self.current_action._debug_data)
         data = {
             "type": "sequence",
-            "current_action_id": self.current_action_index,
-            "content": [elem.repr_dict() for elem in self.actions],
+            "current_action_index": self.current_action_index,
+            "current_action": self.current_action.repr_dict(),
             "debug_data": self._debug_data,
         }
         self.clear_debug_data()

dynamic_stack_decider/dynamic_stack_decider/sequence_element.py

@@ -182,7 +182,7 @@ def param_string(params: dict) -> str:
                 # Spaces for indentation
                 action_label = "  "
                 # Mark current element (if this sequence is on the stack)
-                if stack_element is not None and i == stack_element["current_action_id"]:
+                if stack_element is not None and i == stack_element["current_action_index"]:
                     action_label += "--> "
                 action_label += action["name"] + param_string(action["parameters"])
                 label.append(action_label)
@@ -312,6 +312,9 @@ def to_q_item_model(self):
         # Start with the root/bottom of the stack
         stack_element = self.stack
 
+        # Store the corresponding tree element
+        tree_element = self.tree
+
         # Go through all stack elements
         while stack_element is not None:
             # Sanity check
@@ -327,7 +330,7 @@ def to_q_item_model(self):
             # Set the text of the item
             if stack_element["type"] == "sequence":
                 # Get the names of all actions
-                action_names = [element["name"] for element in stack_element["content"]]
+                action_names = [action["name"] for action in tree_element["action_elements"]]
                 # Join them together and set the text
                 elem_item.setText("Sequence: " + ", ".join(action_names))
             else:
@@ -351,6 +354,9 @@ def to_q_item_model(self):
 
             # Go to next element
             stack_element = stack_element["next"]
+            # Also select the corresponding tree element if there are any
+            if "children" in tree_element and stack_element is not None:
+                tree_element = tree_element["children"][stack_element["activation_reason"]]
 
         return model