Prettify org source block with overlay

prettify-org-source-block.el

(defun org-deck-hide-code-block-delimiters ()
  "Hide #+begin_src and #+end_src lines."
  (save-excursion
    (goto-char (point-min))
    (while (re-search-forward "^[ \t]*#\\+begin_src\\s-*\\S-*" nil t)
      (let* ((begin-start (line-beginning-position))
             (lang-end (match-end 0))
             (end-pos (save-excursion
                        (when (re-search-forward "^[ \t]*#\\+end_src" nil t)
                          (point)))))
        (when end-pos
          ;; Hide #+begin_src and language, replace with [snippet]
          (let ((ov (make-overlay begin-start lang-end)))
            (overlay-put ov 'display "  [snippet]")
            (overlay-put ov 'org-deck-code t))

          ;; Hide #+end_src line
          (save-excursion
            (goto-char end-pos)
            (let ((end-start (line-beginning-position))
                  (end-end (line-end-position)))
              (let ((ov (make-overlay end-start (1+ end-end))))
                (overlay-put ov 'invisible t)
                (overlay-put ov 'org-deck-code t)))))))))


;; To remove, use: (remove-overlays (point-min) (point-max) 'org-deck-code t)