Sublundo

Sublundo brings Vim-like persistent, branching undo/redo to Sublime Text 3. It was inspired by Gundo (and its successor, Mundo).

However, since Sublime Text doesn't have native support for branching undo like Vim, we had to build our own data structure—the UndoTree. An UndoTree is an N-ary tree containing nodes that represent a particular buffer state:

Each node contains, among other attributes, a map associating node IDs to patches. This means that, instead of having to store the entire buffer for each insertion (which often consists of small changes), we only need to store the information necessary to travel back and forth (in both the parent → children and child → parent directions). For example: if A = 'Hello, world!' and B = 'Bye, world!', the A → B translation would be [(-1, 'H'), (1, 'By'), (0, 'e'), (-1, 'llo'), (0, ', wo')]. In Python terms, we'd have:

>>> t = UndoTree()
>>> t.insert('Hello, world!')
>>> t.insert('Bye, world!')
>>> t.text()
'Bye, world!'
>>> t.undo()
# (buffer, patch, cursor position)
('Hello, world!', '@@ -1,7 +1,9 @@\n+H\n-By\n e\n+llo\n , wo\n', None)
>>> t.text()
'Hello, world!'

Installation

1. Install Package Control.
2. Bring up the Command Palette (Command-Shift-P on macOS and Ctrl-Shift-P on Linux/Windows).
3. Select Package Control: Install Package and then select Sublundo when the list appears.

Usage

This package completely overrides the built-in undo and redo commands: whenever you undo or redo an edit, the sublundo command is run instead. So, you should be able to edit, undo, and redo text as you normally would.

When you want to either visualize or navigate the UndoTree, you invoke the Sublundo: Visualize command and then use the following keys to move around:

• up (or k): Move up the current branch (i.e., invoke redo).
• down (or j): Move down the current branch (i.e., invoke undo).
• left (or h): Move to the next branch on the left.
• right (or l): Move to the next branch on the right.

For information on the available settings, see the default settings file.