Yes, in short, I think we both want the "dataflow model" and not the "stateful update" model. If anything should use the dataflow model, it's data analysis!!!

Yes, in short, I think we both want the "dataflow model" and not the "stateful update" model. If anything should use the dataflow model, it's data analysis!!! And yes that's why I mentioned Observable, and I'm glad jashkenas also responded. As far as I understand, it's like a spreadsheet, so when you update your inputs, the outputs become consistent automatically. It's sort of like Make (or perhaps Make in reverse). Dataflow also allows your code to be parallelized. Some scientists don't care about this, but engineers do. It's an eye-opening experience to speed up naive data analysis by 1000x or more with shell scripts and a little C++.