How to disable undo recording within a defun?

How to disable undo recording within a defun?

[S Boucher via Users list for the GNU Emacs text editor]

I'm writting a defun, and would like to disable entirely the recording of undo information while this function is executing.
Is this possible?  If so, what is the way to do this?
Thanks,

Re: How to disable undo recording within a defun?

[Óscar Fuentes]

S Boucher via Users list for the GNU Emacs text editor
<help-gnu-emacs@gnu.org> writes:

> I'm writting a defun, and would like to disable entirely the recording
> of undo information while this function is executing. Is this
> possible?  If so, what is the way to do this? Thanks,

See function buffer-disable-undo and variable buffer-undo-list.

Re: How to disable undo recording within a defun?

[Stefan Monnier via Users list for the GNU Emacs text editor]

>> I'm writting a defun, and would like to disable entirely the recording
>> of undo information while this function is executing. Is this
>> possible?  If so, what is the way to do this? Thanks,
> See function buffer-disable-undo and variable buffer-undo-list.

It's very unusual to disable recording undo, and it is usually
problematic because the undo-records before and after the chunk you want
to skip can't be used together unless the chunk you skip ends up doing
"nothing".

So maybe you're looking for `with-silent-modifications` which can be
used when the modifications to the buffer are "negligible" (typically
in the sense that they don't affect what would get saved into the file).


        Stefan

Re: How to disable undo recording within a defun?

[Michael Heerdegen]

Stefan Monnier via Users list for the GNU Emacs text editor
<help-gnu-emacs@gnu.org> writes:

> So maybe you're looking for `with-silent-modifications` which can be
> used when the modifications to the buffer are "negligible" (typically
> in the sense that they don't affect what would get saved into the file).

Another guess is that the OP wants multiple buffer changes to become a
single undo item.  Doable with change group amalgamating:

 (info "(elisp) Atomic Changes")

Michael.

Re: How to disable undo recording within a defun?

[Emanuel Berg via Users list for the GNU Emacs text editor]

Stefan Monnier via Users list for the GNU Emacs text editor wrote:

> It's very unusual to disable recording undo, and it is
> usually problematic because the undo-records before and
> after the chunk you want to skip can't be used together
> unless the chunk you skip ends up doing "nothing".

Reminds me of world-finance.el where you can transfer huge
sums of money yet do some handy "undoing" in the middle and
most often people are so ignorant and busy anyway mostly up to
no good they don't notice the missing billion in between all
the same ...

-- 
underground experts united
https://dataswamp.org/~incal