Having the program units as records in a database makes it easy to keep track of changes. Whenever a unit is changed in a new revision, the old version is saved to list of old pages and is replaced by the revised version. Each unit has a revision number. Holonforth shows the numbers of all previous revisions of a page. Click on a number to see the previous page. Right-click on the number for a list of all pages related to this revision.
Holonforth manages a logpage for a revision. At a commit a unit page with the new version number in the title is appended at the end of the program. Make the last chapter a text chapter for the revision logs. The revision button calls this page.