Re: new buffer display action: display-buffer-reuse-frame

[martin rudalics]

> I'd like to add display-buffer-reuse-frame to window.el:

This would be a misnomer.  `display-buffer-reuse-window' takes a window
that already shows the buffer and `display-buffer-reuse-frames', albeit
obsolete, meant a similar thing.  `display-buffer-use-some-frame' could
be used.

> This is an alternative to display-buffer-pop-up-frame. I have a couple
> of use cases for it, both based on the premise that there are normally
> two Emacs frames open. This allows other applications to temporarily
> cover one of the frames while still allowing Emacs to be in the
> foreground. It also provides another level of buffer placement control.
>
> - Using ediff to review a file for a commit. There are now three frames;
>    the ediff control frame, the frame containing the old and current file
>    versions under ediff control, and another frame. The user wants to put
>    the log edit buffer in the other frame; they specify
>    display-buffer-reuse-frame as the action, with a frame predicate that
>    excludes the two ediff frames.
>
> - User would like to move a buffer to the other frame. For instance,
>    they just used M-. to find the definition of an elisp function, and
>    they'd like to return to the use of the function, while keeping the
>    definition visible. They specify display-buffer-reuse-frame as the
>    action.
>
> Thoughts?

I think you should add it (together with appropriate NEWS and elisp
manual entries).

martin