zope-traversing

from zope.interface import implementer from zope.traversing.interfaces import ITraversable from zope.traversing.api import traverse # Define a simple traversable object (e.g., a Folder) @implementer(ITraversable) class Folder: def __init__(self, name, parent=None): self.__name__ = name self.__parent__ = parent self.contents = {} def __setitem__(self, name, item): item.__name__ = name item.__parent__ = self self.contents[name] = item def __getitem__(self, name): if name in self.contents: return self.contents[name] raise KeyError(f"No item named '{name}'") def traverse(self, name, furtherPath): # furtherPath is usually ignored for simple dict-like traversal # Default traversal: look up in contents return self.contents[name] def __repr__(self): return f"<Folder '{self.__name__}'>" class Document: def __init__(self, name, content="", parent=None): self.__name__ = name self.__parent__ = parent self.content = content def __repr__(self): return f"<Document '{self.__name__}'>" # Build a hierarchy root = Folder('') products_folder = Folder('products') root['products'] = products_folder products_folder['book1'] = Document('book1', "The first book.") products_folder['book2'] = Document('book2', "The second book.") # Traverse to an item try: item = traverse(root, 'products/book1') print(f"Found item at 'products/book1': {item}") # Attempt to traverse to a non-existent item non_existent_item = traverse(root, 'products/nonexistent') print(f"Found non-existent item: {non_existent_item}") # This line won't be reached except KeyError as e: print(f"Error traversing to 'products/nonexistent': {e} (expected behavior)") # Traverse to a sub-path within an item if it also implements ITraversable # (not shown in this basic example for Document, but would work for nested Folders)