presentation helper for live demo in emacs

pres.el

(defun c6e/pres-forward ()
  (interactive)
  (let ((saved (point)))
    (forward-line)
    (let ((beg (point)))
      (search-forward-regexp "^;;; " nil t)
      (if (= beg (point))
          (goto-char saved)
        (progn
          (recenter 0)
          (beginning-of-line))))))

(defun c6e/pres-backward ()
  (interactive)
  (let ((saved (point)))
    (search-backward-regexp "^;;; " nil t)
    (if (not (= saved (point)))
        (progn
          (recenter 0)
          (beginning-of-line)))))

(define-key evil-normal-state-map (kbd "<f11>") #'c6e/pres-backward)
(define-key evil-normal-state-map (kbd "<f12>") #'c6e/pres-forward)
(define-key evil-insert-state-map (kbd "<f11>") #'c6e/pres-backward)
(define-key evil-insert-state-map (kbd "<f12>") #'c6e/pres-forward)

Searches for the next / previous line starting with ;;; and makes it the first line on the window.