big objects and avoiding deepcopy?

[Aaron Brady]

On Oct 27, 1:10 pm, Terry Reedy <tjre... at udel.edu> wrote:
> bearophileH... at lycos.com wrote:
> > Robert Kern:
> >> This is similar to implementing "Undo" functionality in applications.<
>
> > In a quite-high-level language (like Python, but not necessarily in
> > Python itself) it may become eventually advantageous to add some (even
> > limited) built-in form of undo.
>
> Right now, I believe, one could develop an undo module with undolist and
> undodict classes that wrap instance mutations with an append to an
> undoinfo list.

The trick would be forking instances, so that you could operate on
separate histories/branches independently.  Not necessary for most
undo purposes, of course.