Re: New undo element (fun . args)

[Kim F. Storm]

Richard Stallman <address@hidden> writes:

>     So whether that last undo command added anything to buffer-undo-list
>     or not doesn't seem relevant, as the head of the buffer undo list
>     should be in the undo-equiv-table in both cases,
>
> If an undo command does not generate any undo entries, it will have to
> put into undo-equiv-table a head-of-list that was produced by some
> other command, which may not have been an undo command.  That is
> certainly not supposed to happen.  

I see, yes.

>     So this would be a problem only in the case where (apply ...) is the
>     only action between two undo boundaries. To work around this, it seems
>     to be sufficient to add just one element at the end of Fprimitive_undo
>     in case the undo list hasn't changed at all.
>
> Yes, I think so.

I'll change it to do so.

>
>     BTW, I suppose that the apply undo function is not allowed to change
>     current buffer.
>
> Yes it can.  That is why it can specify a DELTA.

I know.  What I meant was this:

I suppose that the apply undo function is not allowed to 
have SWITCHED BUFFER upon return.

-- 
Kim F. Storm <address@hidden> http://www.cua.dk