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.)

Note that spaced repetition is pretty easy to implement; if your notes are in J Random Format you'd need to munge them anyway.

whats wrong with anki again?

Nothing. Anki is great. But I prefer to have general notes in a text only format that I manage via NValt or simply desktop search. Anki gives me an own file format and forces me to manage my knowledge just within Anki.

It's easy to write plugins for anki though. Anki's data is just stored in a sqlite db.

Thanks for the idea. I will look into that.

My 2c would be to have a special notation in your text notes that labels the data you want to study later. then just parse that and combined with anki's cards you can generate decks easily.