Re: Unreferenced symbols in closures, and a problem with closures in minor modes

[Kelly Dean <kellydeanch@yahoo.com>]

Stefan Monnier wrote:
[...]
> To add&remove functions from hooks, it's much better to make sure you
> actually pass the exact same object (not just one that should hopefully
> be `equal').

Thanks for the fast help and explanations. Per your suggestion I'm avoiding both the equality testing of functions and the unwanted lexical environment this way:
(defun bar-off () (bar 0))
(define-minor-mode bar "Bar" nil " Bar" nil
  (if bar (add-hook 'foo-hook 'bar-off nil t)
    (remove-hook 'foo-hook 'bar-off t)))

although I was tempted to do it this way just to spite the interpreter :-)
(setq bar-off (lambda () (bar 0)))
(define-minor-mode bar "Bar" nil " Bar" nil
  (if bar (add-hook 'foo-hook (symbol-value 'bar-off) nil t)
    (remove-hook 'foo-hook (symbol-value 'bar-off) t)))