old_rwin_resize_01.23.2019

(defun rwin-resize ()
 "Set the height of the R buffer window to my preferred height using 'cond', then open re-builder and re-size its window to my desired size.
This should work regardless of the number of windows and you should be able to call it from any window."
 (interactive)

 ;; start by selecting the top, left window; the re-sizing should start from here
 ;; nicely enough, window-at-side-list seems to grab the desired window, regardless of where point is
 (select-window (car (window-at-side-list nil 'left)))

  ;; set up variables
 ;; current-point gets you out of re-builder jumping you to a point in the current away from where you were editing
 (let ((current-point (point))
       (cb (current-buffer))
       (oldthresh split-width-threshold) ;; or 100
       (right-window-buffer))

 ;; need cond here for the situation where you have a split vertical window at right (e.g., a help buffer)
 (cond
 ;; vertical deletion works, so do that
 ((delete-other-windows-vertically) (message "deleted vertically"))

 ;; RE-Builder AND R have windows, so delete both
 ((and (not (= (length (window-list)) 2))
       (get-buffer-window "*RE-Builder*")
       (get-buffer-window "*R*"))
  (progn
    (delete-window (get-buffer-window "*RE-Builder*"))
    (delete-window (get-buffer-window "*R*"))))

 ;; just RE-Builder has window so delete only that
 ((and (not (= (length (window-list)) 1))
       (get-buffer-window "*RE-Builder*"))
  (delete-window (get-buffer-window "*RE-Builder*")))

 ;; just R has window so delete only that
 ((and (not (= (length (window-list)) 1))
       (get-buffer-window "*R*"))
  (delete-window (get-buffer-window "*R*")))

 ;; something else, unlikely in my setup
 (t (message "some other configuration")))

   ;; if RE-builder is the current buffer, we can't set cb to this
   (when (eq cb (get-buffer "*RE-Builder*"))
     (ibuffer)
     (setq current-point (point))
     (setq cb (get-buffer-create "*Ibuffer*")))

   ;; start R if it's not open already; we have to pause because R can't keep up w/ emacs
   (when (not (bufferp (get-buffer "*R*")))
     (split-window-vertically)
     (other-window 1)
     (R)
     (sit-for 5))

   ;; account for a situation where a help buffer exists in the right window
   (when (window-in-direction 'right)
     (progn
       (select-window (window-in-direction 'right))
       (setq right-window-buffer (current-buffer))
       (delete-window)))

   ;; now start the re-sizing process
   ;; use 'cond' here to account for various possible R session/window setups
   (cond

    ;; 1. R is not open and no window exists for it
    ((and (not (get-buffer-window "*R*" 0))
          (not (bufferp (get-buffer "*R*"))))
     (progn
       (setq split-width-threshold most-positive-fixnum)  ;; return to 100
       (R)
       (switch-to-buffer cb)
       (pop-to-buffer "*R*" t t)
       (font-lock-mode -1)
       (eldoc-mode -1)
       (set-window-text-height (car (window-list)) 15)
       (switch-to-buffer-other-window cb)
       (setq split-width-threshold oldthresh)))

    ;; 2. R is open, but no window exists for it
    ((and (not (get-buffer-window "*R*" 0))
          (bufferp (get-buffer "*R*")))
     (progn
       (setq split-width-threshold most-positive-fixnum)  ;; return to 100
       (switch-to-buffer-other-window "*R*" t)
       (font-lock-mode -1)
       (eldoc-mode -1)
       (set-window-text-height (car (window-list)) 15)
       (setq split-width-threshold oldthresh)))

    ;; 3. R is open and occupies its usual position on the screen
    ((and (get-buffer-window "*R*" 0)
          (bufferp (get-buffer "*R*"))
          (not (= (length (window-list)) 1)))
     (progn
       (setq split-width-threshold most-positive-fixnum)  ;; return to 100
       (pop-to-buffer "*R*" t t)
       (font-lock-mode -1)
       (eldoc-mode -1)
       (set-window-text-height (car (window-list)) 15)
       (setq split-width-threshold oldthresh)))

   ;; 4. R is the only buffer w/ a window
   ((and (get-buffer-window "*R*" 0)
         (= (length (window-list)) 1))
    (progn
      (setq split-width-threshold most-positive-fixnum)  ;; return to 100
      (pop-to-buffer "*R*" t t)
      (set-window-text-height (car (window-list)) 15)
      (font-lock-mode -1)
      (eldoc-mode -1)
      (setq split-width-threshold oldthresh))))

   ;; call this now so that re-builder ends up in the desired spot
   (switch-to-buffer-other-window cb)

   ;; open re-builder, set the window to the desired size, and jump back to where you were in the other window
   (progn
     (re-builder)
     (set-window-text-height (car (window-list)) 3))
   (switch-to-buffer-other-window cb)
   (goto-char current-point)

 ;; last step to restore a side window if it was active
 (when right-window-buffer
   (display-buffer-pop-up-window right-window-buffer nil)))
   )