Tutorial File #4

Useful General Commands

The following is a list of general commands.
- ```i``` to change to Insert mode
- ```v``` to change to Select mode
- ```s``` to save to a file (you may specify the file as the first argument)
- ```z``` to undo your last change (doesn't work on extremely large files)
- ```y``` to redo your last undo (doesn't work on extremely large files)

Undo and Redo

The ```z``` and ```y``` commands respectively allow you to undo and redo changes.
Changes are stored as states, which are wrappers around tuples of (caret, text).
These do not work with large files as compressing the text takes a long time. This results in extremely slow file editing.
States are stored linearly in Dim as list data structure. A pointer is stored to the current state.
Each new change advances the pointer and writes or overwrites a new state at its address.
Each undo subtracts it by one element. Each redo increases it by one element. 

Quitting

Press escape in Command mode to quit the editor.
