Can you undo a design pattern?
The memento pattern is a software design pattern that provides the ability to restore an object to its previous state (undo via rollback). The memento pattern is implemented with three objects: the originator, a caretaker and a memento. The originator is some object that has an internal state.
What is undo/redo option?
The undo function is used to reverse a mistake, such as deleting the wrong word in a sentence. The redo function restores any actions that were previously undone using an undo. For example, if you typed a word, and then deleted it using an undo, the redo function restores the word you deleted (“undid”).
How should undo/redo work?
- Undo is an interaction technique which is implemented in many computer programs.
- In most Microsoft Windows applications, the keyboard shortcut for the undo command is Ctrl+Z or Alt+Backspace, and the shortcut for redo is Ctrl+Y or Ctrl+Shift+Z.
What happens if you use undo and Redo feature?
To undo an action, press Ctrl + Z. The Undo and Redo features let you remove or repeat single or multiple typing actions, but all actions must be undone or redone in the order you did or undid them – you can’t skip actions.
What is pattern and design pattern?
In software engineering, a design pattern is a general repeatable solution to a commonly occurring problem in software design. A design pattern isn’t a finished design that can be transformed directly into code. It is a description or template for how to solve a problem that can be used in many different situations.
Which design pattern makes provisions for an undo or redo function?
If you’re talking GoF, the Memento pattern specifically addresses undo. As others have stated, the command pattern is a very powerful method of implementing Undo/Redo.
Which toolbar has undo and redo button?
quick access toolbar
To undo or redo only the most recent action, left-click the Undo (CTRL+Z) or Redo (CTRL+Y) button on the quick access toolbar. To display a list of multiple recent actions for selection, click the arrow next to the Undo or Redo command icon.
How do you implement undo and redo?
If “UNDO” string is encountered, pop the top element from Undo stack and push it to Redo stack. If “REDO” string is encountered, pop the top element of Redo stack and push it into the Undo stack.
Which is the best design pattern for undo?
Memento pattern would be much costlier then Command patterns for Undo/Redo functionality. Capturing and Restoring object state will be quite an expensive affair compared to just doing or undoing an action on any compatible object. Not the answer you’re looking for? Browse other questions tagged design-patterns undo or ask your own question.
How is the undo system used in Stack Overflow?
The key here is that you can use your undo/redo system as the primary command system for your editor. Instead of writing the system such as “create undo object, modify the document” you can “create undo object, execute redo operation on undo object to modify the document”.
How to deal with supporting an ” undo ” feature in your application?
Closed 10 years ago. In general, how do you deal with supporting an “undo” feature in your application? I have worked on web apps and desktop apps alike, and I have never really felt comfortable with any “undo” system I’ve made. I believe it should be Command design pattern. Here is article about multilevel Undo/Redo with Command pattern.
What’s the difference between a paste and an undo?
In other words, the undo operation for a cut is paste and the undo operation for a paste is cut. This applies to much simpler operations as typing and deleting text. The key here is that you can use your undo/redo system as the primary command system for your editor.