Jupyter notebooks are almost a huge step forward for programming. The instant feedback, saving of partial program state, and visualizations mixed in are amazing and fun to work with. The fact that it's taking place in a browser, you don't have modal editing with Vim, you don't get plugin support (like MyPy), and you don't have intellisense is a huge step backwards.

I'm hoping that someone addresses these issues, I know VSCode is trying, and Scala "Metals" worksheets are another similar concept (though different, it puts variable values in comments next to code as you update the code).

I feel like all of these are a step closer than what the Lighttable/Eve teams were shooting for, but not quite the next generation way of coding that it could be.