Playing with a spacemacs-like scrolling micro state

gistfile1.el

;; Old syntax

(evil-leader/set-key
  ","  'hfj/scroll-page-down
  "."  'hfj/scroll-page-up
  )

(defun hfj/scroll-page-overlay-map ()
  "Set a temporary overlay map to easily scroll through a file."
  (set-temporary-overlay-map
   (let ((map (make-sparse-keymap)))
     (define-key map (kbd ",") 'hfj/scroll-page-down)
     (define-key map (kbd ".") 'hfj/scroll-page-up)
     (define-key map (kbd "SPC") '(lambda () (interactive) t))
     map) t))

(defun hfj/scroll-page-micro-state-doc ()
  "Display a short documentation in the mini buffer."
  (echo "Scroll Page micro-state: .: page up  ,: page down"))

(defun hfj/scroll-page-up-or-down (direction)
  "-1 for down, 1 for up"
  (interactive)
  (if (< direction 0)
      (evil-scroll-page-down 1)
    (evil-scroll-page-up 1))
  (hfj/scroll-page-overlay-map)
  (hfj/scroll-page-micro-state-doc))

(defun hfj/scroll-page-up ()
  "Micro state page up"
  (interactive)
  (hfj/scroll-page-up-or-down 1))

(defun hfj/scroll-page-down ()
  "Micro state page down"
  (interactive)
  (hfj/scroll-page-up-or-down -1))