Thank you! I didn't know about code.interact, but IPython.embed I have used in the past. My point was more that I would like a way to drop to an IPython prompt when my program crashes, I really don't like the solution of having to modify the code to insert a statement where I think my program is going to crash.

In any case I think there was a way to examine variables from up the stack of a stack trace or something like that.. bit too lazy to look it up right now. Regardless, working with a REPL in emacs is pretty great ;)

I think there is a way to do jupyter from emacs (or at least there was a way to do ipython notebooks), but I haven't used it extensively, just tested it once I think. I guess I'm pretty satisfied with the REPL and haven't found a need to have intermediate output during the running of a program.

What I do like about the matpotlib interactive approach is being able to watch the progress of a loop very easily, which is hard to do from a notebook, although there are some ways, but they are either hacky or require some pretty sophisticated things like custom widgets.