> I think it is a good thing that notebooks separate instructions and re-execute manually by default. The cost of the alternative is just too high.
Maybe add a "lock" toggle so a user can block a cell from being automatically executed? The heavy numeric setup tasks could then be gathered in a few cells and locked, leaving the lighter plotting & summary stats cells free to update reactively.
Toggle a whole environment and intrepeter's behavior? Do you know how much architecture that would involve? That's like trying to tell IDLE to be able to both delete or keep your variables on exit, or the JVM to have a toggle switch for memory and garbage management.
Why doesn't the developer make themselves useful and simply write a save function that freezes their buffer variable values to a text, json or SQLite file that they can read from or stream rather than trying to set back a whole community years of progress in an effort to accommodate perhaps entitled or lazy devs.
Can you even imagine the architectural costs of trying to accommodate streaming data and timestamped data as opposed to you just writing your own stuff to file?
I think adding a toggle to run or not run a cell would be a trivial change, something like adding a property to the cell (https://raw.githubusercontent.com/jupyter/notebook/master/no...) and checking whether that is set or not before running the contents.
Maybe add a "lock" toggle so a user can block a cell from being automatically executed? The heavy numeric setup tasks could then be gathered in a few cells and locked, leaving the lighter plotting & summary stats cells free to update reactively.