Re: save-frame-excursion?

[Robert Goldman <rpgoldman@sift.info>]

Stefan Monnier wrote:
>> Currently we use this in Org-mode to save frame excursion:
>> (defmacro org-save-frame-excursion (&rest body)
>>   "Eval BODY and return to the currently selected frame."
>>   (let ((frame-var (gensym "FRAME")))
>>     `(let ((,frame-var (selected-frame)))
>>        (unwind-protect
>>            (progn ,@body)
>>          (select-frame-set-input-focus ,frame-var)))))
> 
>> This was required when selecting a date for an Org entry.
>> Org has a mechanism that lets the user browse the calendar
>> while the cursor is still in the minibuffer (see org-read-date).
> 
>> When the calendar is displayed in a separate frame, this
>> mechanism was broken because org-read-date was losing the
>> focus.
> 
> Do you know when/why it lost the focus?

The org frame lost focus because focus shifted to the frame that
contained the *Calendar* buffer.  The interaction in the *Calendar*
buffer was protected by save-excursion and save-window-excursion.  That
was enough to save the state /within/ the frame containing the org
buffer, but was /not/ enough to restore focus to the original frame.
> 
> What was used before this macro (i.e. which part of this macro is the
> important one)?
> 
>> Is this a pattern that other developers already met?
> 
> Well, there's save-selected-window, as well as with-selected-window,
> which cover similar grounds, but without knowing more details it's hard
> to tell.

I am not that experienced in this area, but as far as I can tell
save-window-excursion covers similar ground, but only controls what
window is selected /within a given frame/.  So this macro, on which I
based org-save-frame-excursion covers similar ground, but it does not
subsume this macro.

I hope this helps,

Robert