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undo/redo functionality for arbitrary python classes

Project description

undoredo
--------

undo/redo functionality for arbitrary python classes

Supports Python 3. Might work in Python 2.

> Author: Ross Anderson ([rosshamish](https://github.com/rosshamish))

### Installation

```
pip install undoredo
```

### Usage

Any class can gain undo/redo functionality by doing the following:

- keep around an instance of UndoManager
- annotate undoable methods with the @undoable decorator
- implement do(), undo(), and redo() methods as shown in the following example
- implement copy(), and restore(obj) methods
- where copy() returns a copy of the object (probably a deep copy)
- where restore(obj) restores the calling object to the state of the passed object

### Example

```
import undoredo

class Counter(object):
def __init__(self, value=0):
self.undo_mgr = undoredo.UndoManager()
self.value = value

@undoredo.undoable
def increment(self):
self.value += 1

@undoredo.undoable
def decrement(self):
self.value -= 1

def do(self, command):
return self.undo_mgr.do(command)

def undo(self):
return self.undo_mgr.undo()

def redo(self):
return self.undo_mgr.redo()

def copy(self):
return Counter(self.value)

def restore(self, counter):
self.value = counter.value

c = Counter(0) # 0
c.increment() # 1
c.increment() # 2
c.undo() # 1
c.redo() # 2
```

### License

GPLv3

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