HOOK should be a symbol, and FUNCTION may be any valid function. If
HOOK is void, it is first set to nil. If HOOK's value is a single
-function, it is changed to a list of functions.
-
-Note: if you make a hook variable buffer-local, copy its value before
-you use `add-hook' to add to it. For example,
-
- (make-local-variable 'foo-hook)
- (if (boundp 'foo-hook)
- (setq foo-hook (copy-sequence foo-hook)))
- (add-hook 'foo-hook 'my-foo-function)"
+function, it is changed to a list of functions."
(or (boundp hook) (set hook nil))
;; If the hook value is a single function, turn it into a list.
(let ((old (symbol-value hook)))
(memq function (symbol-value hook)))
(set hook
(if append
- (nconc (symbol-value hook) (list function))
+ (append (symbol-value hook) (list function))
(cons function (symbol-value hook))))))
(defun remove-hook (hook function)
nil ;Do nothing.
(let ((hook-value (symbol-value hook)))
(if (consp hook-value)
- (setq hook-value (delete function hook-value))
+ (if (member function hook-value)
+ (setq hook-value (delete function (copy-sequence hook-value))))
(if (equal hook-value function)
(setq hook-value nil)))
(set hook hook-value))))