[hokkos]

I see no problem with the set method name, this is what is used in other lib in other languages. When you use an immutable lib you understand the meaning and that every operation create a new base object.

This is extremely useful for undo/redo, it basically comes for free with it. You no longer have to deal with invisible mutation, listener, event, you just generate the ui on each change from the base to the leaf, and everything is always correct for free. The advantage over an undo stack is that there is a re-utilization of unchanged intermediate data structure (what is change is only the path from the base to the changed element), so you can add a simple ref check in the ui to not redraw of the underlying data has not changed. So the perf come for free.