[thomasballinger]

The Jupyter models is hard for this, but if you only allow in-order execution (like a repl, say IPython whose kernel is used in Jupyter) you could do something like this.

We tried plugging in the rlundo tool https://github.com/thomasballinger/rlundo to IPython, it works ok, see http://ballingt.com/interactive-interpreter-undo/ for the long story.

I wanted something like this for live programming and felt like I needed to write my own interpreter because the behavior you need is so different: http://dalsegno.ballingt.com