Thanks for your reply. Working on the stuff, I encountered the following problem: If, in “ display-buffer-alist”, I have the entry:

      ("[ ]?Packages[ ]?" (display-buffer-reuse-window display-buffer-pop-up-frame)
       (pop-up-frame-parameters
        (tool-bar-lines . 1)
	(left . 1)
	(left-fringe . 2)
        (top . 0)
	(height . 65)
	(width . 149)
	(font . "SF MONO-18")
        (line-spacing . 3)
	))

then, contrary to what is promised, this does not pop up a new frame. I figured out that the problem goes away if, in “packages.el”, I replace in the defun “list-packages” the  code (switch-to-buffer buf) by (pop-to-buffer buf). My question is how to do this on the level of customizing “display-buffer-alist”. I didn’t find anything in this regard in the manuals.




> Am 22.10.2019 um 10:43 schrieb martin rudalics <rudalics@gmx.at>:
> 
> > There is no detailed example in the emacs manuals on how to migrate
> > from using "special-display-frame-alist" and
> > "special-display-regexps" to "display-buffer-alist."
> 
> I'm not sure whether I'll be able to come up with something reasonable
> in this regard, mainly because I've never been able to understand the
> special display function mechanism.
> 
> > E.g., how to migrate from
> >
> > (setq special-display-frame-alist
> >     (quote
> >      ((height . 42)
> >      (width . 83)
> >      (left . 770)
> >      (unsplittable)
> >      (tool-bar-lines . 0)
> >      (left-fringe . 0)
> >      (right-fringe . 0)
> >      (line-spacing . 0)
> >      (font . "Monaco-12")
> >      (top . 110))))
> >
> >   and
> >
> > (setq special-display-regexps '((".*output*" (right-fringe . 0) (left-fringe . 0) (top . 330) (left . 152)
> >    (width . 86) (height . 32)
> >    (tool-bar-lines . 0) (font . "Menlo-10") (menu-bar-lines . 0)))
> 
> You can try the following untested snippet (your regxp looks a bit
> odd, BTW):
> 
> (setq my-special-display-frame-alist
>      (quote
>       ((height . 42)
> 	(width . 83)
> 	(left . 770)
> 	(unsplittable)
> 	(tool-bar-lines . 0)
> 	(left-fringe . 0)
> 	(right-fringe . 0)
> 	(line-spacing . 0)
> 	(font . "Monaco-12")
> 	(top . 110))))
> 
> (setq my-special-display-regexps
>      '((".*output*"
> 	 (right-fringe . 0)
> 	 (left-fringe . 0)
> 	 (top . 330)
> 	 (left . 152)
> 	 (width . 86)
> 	 (height . 32)
> 	 (tool-bar-lines . 0)
> 	 (font . "Menlo-10")
> 	 (menu-bar-lines . 0))))
> 
> (setq display-buffer-alist
>      `((".*output*"
> 	 (display-buffer-reuse-window
> 	  ; display-buffer-same-window
> 	  ; display-buffer-pop-up-window
> 	  display-buffer-pop-up-frame)
> 	 (reusable-frames . 0) (inhibit-switch-frame . nil)
> 	 (pop-up-frame-parameters . ,(append (cdr my-special-display-regexps)
> 					       special-display-frame-alist)))))
> 
> where you have to comment-in the respective alist functions when you
> use 'same-window' or 'same-frame' in your 'special-display-regexps'
> settings (apparently you don't).
> 
> I can put a similar example into the Elisp manual (Eli would have to
> figure out the details to omit or add) but note the following two not
> entirely negligible differences:
> 
> 'special-display-popup-frame' (the default for
> 'special-display-function') uses
> 
>       (when (cdr (assq 'same-window args))
> 	 (condition-case nil
> 	     (progn (switch-to-buffer buffer nil t) (selected-window))
> 	   (error nil)))
> 
> which has no direct equivalent in the 'display-buffer-alist'
> ecosystem.  I used 'display-buffer-same-window' instead but that does
> not obey options like 'switch-to-buffer-in-dedicated-window' or
> 'switch-to-buffer-preserve-window-point'.  Which means that for a
> faithful migration you would have to write your own action function
> here.
> 
> The second difference derives from the fact that
> 'special-display-popup-frame' marks the window on a new frame as
> dedicated to its buffer.  This is no more needed in the
> 'display-buffer-alist' world because there the 'quit-restore' window
> parameter takes care of the problem the former tries to solve.  Still
> this means a behavioral difference that should be mentioned.  I
> _cannot_ add a non-nil 'dedicated' alist entry because that would be
> applied by any other action function ('display-buffer-pop-up-window'
> foremost) too.
> 
> Also I have left out details like the function to be called when the
> car of the ARGS argument of 'special-display-popup-frame' is a symbol
> or how to treat 'special-display-buffer-names' ...
> 
> martin