(defun fwoar/center-defun ()
  (interactive)
  (cl-destructuring-bind (a . b) (bounds-of-thing-at-point 'defun)
    (save-excursion
      (let ((s (progn (goto-char a) (line-number-at-pos)))
            (e (progn (goto-char b) (line-number-at-pos))))
        (evil-scroll-line-to-center (+ s -1 (ceiling (- e s) 2)))))))