Undo / redo

[c4lliope]

With a little elbow grease, (knuckle grease?)
Hierarch Pose could keep a record of the changes that have been made to the source code;
This log may look along the lines of:

REPLACE [12,15]: "hello"
REPLACE [101,120]: function(x, y) {\nreturn x * y\n}

Where each line records a change, the indices in the original file, and the replaced text.
Alongside git references, some kind of change log would be sufficient to re-play the upgrades that have been made in a file.