The Memento pattern lets you capture an object's internal state in a separate snapshot object and restore it later, without exposing how that state is stored.
Here the originator is an Editor that holds some content (a string). A Memento wraps a copy of that content in a private field so nobody outside can read it directly.
Implement two methods on Editor:
The Memento class is already written for you. It keeps the state in a private field and only hands it back through get_state, which is meant for the editor's own use.
Once this works, you can take a snapshot, keep editing, then jump back to exactly where you were.
class Memento:
def __init__(self, state):
self._state = state
def get_state(self):
return self._state
class Editor:
def __init__(self):
self.content = ""
def save(self):
"""Capture the current content in a Memento and return it."""
# TODO: create a Memento holding self.content and return it
pass
def restore(self, memento):
"""Set content back to the state stored in the given memento."""
# TODO: read the memento's state and assign it to self.content
pass
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The Memento pattern lets you capture an object's internal state in a separate snapshot object and restore it later, without exposing how that state is stored.
Here the originator is an Editor that holds some content (a string). A Memento wraps a copy of that content in a private field so nobody outside can read it directly.
Implement two methods on Editor:
The Memento class is already written for you. It keeps the state in a private field and only hands it back through get_state, which is meant for the editor's own use.
Once this works, you can take a snapshot, keep editing, then jump back to exactly where you were.
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