[xedrac]

> They were programmed in lisp the whole way down and could be run code interpreted for convenience or compiled to microcode for efficiency. You could open up system functions in the editor, modify and compile them while the machine was running. Everything worked in a single address space, programs could talk to each other in ways operating systems of today couldn’t dream of.

So this is basically expanding Emacs to actually be the operating system. There's definitely some allure to it. Awhile back, I was hacking on the Lem editor for Common Lisp, using the Lem editor itself. It was great until I made a mistake in some code that restricted my ability to edit the code, sort of like performing brain surgery on my self and snipping a nerve that controlled my arms. It was amazing to have that immediate feedback loop, but in a world that is striving to find new ways to minimize human error, I'm just not sure it'd hold up.

[mst]

Pervasive rollback in a sufficiently compartmentalised bit of the UI that it's really hard to break would seem like the ideal theoretical solution but practically really quite tricky to introduce to an environment retroactively.

(I've been pondering this problem recently for something I'm working on an introducing it from the ground up is bending my brain hard enough, others may be better at it though ;)