USERGUIDE.md

Using Unda

Installation

First, install Unda by the pip command (if you haven't already):

pip install unda

Basic Usage

Unda currently provides three ways of handling undo/redo for your objects:

• Use an UndoClient object pointing to your custom object.
• Code your object to inherit from the UndoObject class.
• Use an UndoManager object.

The usage guides for each method below are very basic and aimed at beginners to Python, thus I recommend you always check the docstrings of each method and class to understand the full capabilities of Unda.

Using UndoClient

The UndoClient manages the undo/redo functionality on behalf of your object.

• Let's assume this is your custom class...:

# Nothing fancy here, just an example. 
# Bonus points if you skate though.

class Skateboard:

    def __init__(self, name):
        self.name = name
        self.flipped = False
        
    def do_a_kickflip(self):
        self.flipped = True
        print('Board flipped successfully.')

• ...and you've got an instance of the class, like so:

board = Skateboard('Varial')  # Just a skateboard named Varial.

• Import the UndaClient object and create an instance for our board/object:

from unda import UndaClient
client = UndaClient(board)

• Next, we update the Client. When using Unda in general, "updating" simply means saving a state to the undo stack which we can go back to when we call undo(). So remember, always call update() when you need to be able to undo whatever happens next.

client.update()

• Now that we've got our client all set up, we can go crazy on this object and make whatever changes we like to its attributes...:

board.do_a_kickflip()

• As you can see, the do_a_kickflip() method is supposed to change the flipped attribute of our object. The value of the flipped attribute should now be True. We can confirm using

print(board.flipped)  # This should print True currently.

• And if we need to undo, it's as easy as:

board = client.undo()

• We can confirm if the action was actually undone using

print(board.flipped)  # This will print False

• If we need to redo the action, we call the redo() function.

board = client.redo()
print(board.flipped)  # This will print False

That's basically all you need to know to use Unda.