better comment-dwim

gistfile1.el

(defun dwim-entire-line (function)
  (if (region-active-p)
       (funcall function (region-beginning) (region-end))
     ;; else
     (funcall function (point-at-bol) (point-at-beginning-of-next-line))))

(global-set-key (kbd "M-;") (lambda () (interactive)
  (dwim-entire-line 'comment-or-uncomment-region)))

funcall: Symbol's function definition is void: point-at-beginning-of-next-line

Looks like point-at-beginning-of-next-line is a custom function of yours. Source?