Re: managing windows in two frames

[martin rudalics <rudalics@gmx.at>]

 > (defun display-buffer-reuse-frame (buffer alist)

I'd call it `display-buffer-other-frame' ("reuse" currently has the
connotation that a window already displays the buffer in question).

 >   "Display BUFFER in an existing frame other than the current frame.
 > If successful, return the window used; otherwise return nil.
 >
 > If ALIST has a non-nil `inhibit-switch-frame' entry, avoid
 > raising the frame.
 >
 > If ALIST has a non-nil `pop-up-frame-parameters' entry, the
 > corresponding value is an alist of frame parameters to give the
 > new frame."
 >   (let* ((frame (car (filtered-frame-list

This is overly restrictive.  We should be able to choose any window on
any frame.  If necessary, we can invent a new alist element for picking
a frame.

 > 		      (lambda (frame)
 > 			(and
 > 			 (not (eq frame (selected-frame)))
 > 			 (not (window-dedicated-p
 > 			       (or
 > 				(get-lru-window frame)
 > 				(frame-first-window frame)))))))))

The lru and first window of that frame could denote the same window.
Here too we can add a new alist element for picking the window.

 > 	 (window
 > 	  (and frame
 > 	       (or
 > 		(get-lru-window frame)
 > 		;; lru-window can be nil if window was deleted, by ediff for example

Can you give a scenario?  `get-lru-window' doesn't consider/return
deleted windows IIRC.  It can return nil if all windows are dedicated or
slelected.

 > 		(frame-first-window frame-2))))

What is frame-2 ?

 > 	 )
 >     (when window
 >       (prog1 (window--display-buffer
 > 	      buffer window 'frame alist display-buffer-mark-dedicated)
 > 	(unless (cdr (assq 'inhibit-switch-frame alist))
 > 	  (window--maybe-raise-frame frame))))
 >     ))
 >
 > (defun display-buffer-other-window-or-frame (buffer alist)
 >   "Depending on `current-prefix-arg', show BUFFER in another window or frame.
 > If current-prefix-arg is:
 > '(4) - from C-u; show buffer in another window in current frame, creating new if needed.
 > '(16) - from C-u C-u; show buffer in another frame, creating new if needed.
 > other - return nil."

`display-buffer' decisions are currently not based on a prefix argument
given.  Maybe we can reconcile your idea with Stefan's proposal to use
special prefixes for `display-buffer'-based functions.

 >   (or
 >    (cond
 >     ((equal current-prefix-arg '(4)) ;; other window
 >      (or (display-buffer-use-some-window buffer '((inhibit-same-window . t)))
 > 	 (display-buffer-pop-up-window buffer nil)))
 >
 >     ((equal current-prefix-arg '(16)) ;; other frame
 >      (or (display-buffer-reuse-frame buffer '((reusable-frames . visible)))   ;; reuse a window in other frame
 > 	 (display-buffer-pop-up-frame buffer nil)))
 >
 >     (t nil)
 >
 >     )))
 >
 > (defun sal-move-to-other-frame ()
 >   "Move current buffer to a window in another frame."
 >   (interactive)
 >   (let ((buffer (current-buffer)))
 >     (switch-to-prev-buffer nil 'bury)
 >     (let ((display-buffer-overriding-action
 > 	   '((display-buffer-reuse-frame buffer display-buffer-pop-up-frame)
 > 	     . '((reusable-frames . visible)))))   ;; reuse a window in other frame
 >       (display-buffer buffer))))
 >
 >
 > The use case for these:
 >
 > I use two Emacs frames, side by side, filling the screen. This allows
 > two things:
 >
 > 1) opening other applications next to an Emacs frame

If Emacs fills the screen there doesn't seem much space left for other
applications ;-)

 > 2) navigating between frames for horizontal movement (using window
 > manager keys), and between windows for vertical movement (using Emacs
 > keys).
 >
 > With one Emacs frame, split both horizontally and vertically, I find it
 > difficult to navigate among the windows.

I'm using M-S-left, M-S-up ... to navigate to the window in that
direction.

 > `display-buffer-reuse-frame' allows displaying a buffer in the other
 > frame, without always creating a new frame.

Such functionality is missing, indeed.

 > `display-buffer-other-window-or-frame' gives the user flexible control
 > of all buffer display functions, via the prefix arg.

We have to decide how to integrate pefix arguments in buffer display
functions.  So far, I don't know of a proposal that allows, for example,
to use the "same" window, thus overriding an application that wants to
display the buffer in another window.

martin