def backtrack()

in textworld/generator/chaining.py [0:0]

• 30 lines of code
• 13 McCabe index (conditional complexity)

    def backtrack(self, node: _Node) -> Iterable[_Node]:
        """
        Backtrack to earlier choices to generate parallel quests.
        """

        if node.breadth >= self.max_breadth or node.length >= self.max_length:
            return

        parent = node
        parents = []
        while parent.dep_parent:
            if parent.depth == 1 and not self.options.independent_chains:
                break
            parents.append(parent)
            parent = parent.dep_parent
        parents = parents[::-1]

        for sibling in parents:
            parent = sibling.dep_parent
            rules = self.options.get_rules(parent.depth)
            assignments = self.all_assignments(node, rules)
            if self.rng:
                self.rng.shuffle(assignments)

            for partial in assignments:
                action = self.try_instantiate(node.state, partial)
                if not action:
                    continue

                if action in sibling.used:
                    continue

                if not self.check_action(parent, node.state, action):
                    continue

                state = self.apply(node, action)
                if not state:
                    continue

                used = sibling.used | {action}
                yield _Node(node, parent, state, action, rules, used, node.breadth + 1)