John Wiegley <jwiegley@gmail.com> writes:

> This is functionality I'd like to add to rect.el. It allows you to specify a
> rectangular region, and then edit just the contents of that rectangle in a
> separate buffer. When finished (C-c C-c), it replaces the old rectangle using
> insert-rectangle with the new contents.
>
> I'd appreciate comments on usability, fitness, etc.

Also, after inserting the new rectangle, undo should restore buffer as
before, just need for this to add `buffer-disable-undo` in first fn and
`buffer-enable-undo` in second fn.