[fsavard]

There certainly is, I coded one myself, but I never made any effort to publicize it.

http://www.fsavard.com/flow/2012/12/diff-revision/

Basically you take notes like you normally would and the "diffs" of your notes become the elements you will review using spaced-repetition style intervals.

Drawbacks:

- It's not exactly user friendly in its current implementation.

- There isn't any way to give yourself a grade based on how well you remembered a piece of information.

- You must take care to write notes in small blurbs before running the "diff" command, otherwise I end up with large chunks of text to revise and I won't review properly.

- The lack of question-answer mechanism pretty much bypasses the whole "active recall" principle, or whatever that was called.

(Edit: spacing.)