;; evaluate this file, sexp after sexp, and follow the comments.

;; set a minimal environment
(progn
  (custom-set-faces
   '(current-tab-face ((t ( :inherit 'default-face  :foreground "lightblue" :bold t :underline t))))
   '(odd-tab-face    ((t ( :background "red"    :foreground "white" ))))
   '(even-tab-face   ((t ( :background "green"  :foreground "black")))))
  (set-frame-parameter (selected-frame) 'tab-bar-lines 4)
  (set-frame-parameter (selected-frame) 'menu-bar-lines 0))

;; this is a definition of a tab as a window configuration
(defun make-wc-tab (parms)
  ;; save curent win config
  (setq sym (make-symbol "winconfig"))
  (set sym  (current-window-configuration))
  ;; make a tab that keeps a window configuration. When it is created,
  ;; it memories the current win config. When it is activated, it
  ;; restores the memorized win config
  (make-terminal-frame
   (list '(tab . t)
	 '(tab:name . "WinC")
	 '(tab:activate
	   .
	   (lambda ()
	     (set-window-configuration
	      (eval (cdr (assoc 'tab:env (frame-parameters) ) ) ) ) ) )
	 ;; save the current win config into the tab environment
	 (cons 'tab:env sym) ) ) )

;; make a first tab keeping current win config
(make-wc-tab nil)

;; alter the window configuration
((lambda nil
   (split-window-vertically)))

;; make a second tab keeping current win config
(make-wc-tab nil)

;; alter the window configuration
((lambda nil
   (split-window-horizontally)))

;; make a third tab keeping current win config
(make-wc-tab nil)

;; keep only the current window
(delete-other-windows)

;; now activate the tabs that keep the memorized win config.  this
;; function disovered a bug in window configuration . LOL.  If you
;; change the tab-bar-lines or menu-bar-lines after creating a tab
;; and before activatin it here, emacs crashes. LOL.

;; activate the second
(set-frame-parameter (selected-frame) 'current-tab 1)

;; the third
(set-frame-parameter (selected-frame) 'current-tab 2)

;; the first again
(set-frame-parameter (selected-frame) 'current-tab 0)

;; dump frame params
(progn
  (setq  eval-expression-print-length 5000
	 eval-expression-print-level  5000
	 print-level 5000
	 )
  (frame-parameters) )

;; that's all for now.