undo_redo_app

Memento pattern that used for undo and redo.

Technical

I am using cursor index position to point the actual data.

Data 1	Data 2	Data 3	Data 4
			(*)

When doing undo:

Data 1	Data 2	Data 3	Data 4
		(*)

Cursor will move down the index, and send data 3 to ui/view

When doing redo:

Data 1	Data 2	Data 3	Data 4
			(*)

Cursor will move up the index, and send data 4 to ui/view

When undo and inserting a new value:

Process 1: undo... (for example, 2x undo)

Data 1	Data 2	Data 3	Data 4
	(*)

Process 2: user insering a new data: the datas that > cursor index will be removed and replaced by new data

Data 1	Data 2	My new data
		(*)