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(remove-hook, add-hook): Copy existing list before modifying.

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This commit is contained in:
Richard M. Stallman 1994-09-21 05:19:43 +00:00
parent ec265841c9
commit aa09b5ca24
1 changed files with 4 additions and 11 deletions
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15
lisp/subr.el
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@ -551,15 +551,7 @@ FUNCTION is added at the end.
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)))
@ -570,7 +562,7 @@ you use `add-hook' to add to it. For example,
(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)
@ -584,7 +576,8 @@ list of hooks to run in HOOK, then nothing is done. See `add-hook'."
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))))