RE: [External] : Re: how to force auto-save of buffers not visiting files, right now?

[Drew Adams]

> Normally you should be able to `undo' if
> something went wrong.  Even when the buffer
> has no associated file.

Yes.  Yet another reason that buffers such as
*Pp Eval Output*, and even read-only buffers
such as *Messages*, should have undo by default.

Visited buffers are sometimes usefully edited.
We're not gaining much nowadays, I think, by
omitting undo from such buffers by default.

(In `pp+.el' I added undo to *Pp Eval Output*,
at least.)