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[xemacs-hg @ 2002-06-23 22:03:32 by youngs] 2002-06-22 Ville Skyttä <ville.skytta@xemacs.org> * subr.el (add-to-list): Sync with GNU Emacs 21.2, adding the "&optional append" argument.
author youngs
date Sun, 23 Jun 2002 22:03:33 +0000
parents 79c6ff3eef26
children 1e9272790fe0
comparison
equal deleted inserted replaced
877:e54d47b2d736 878:64f38afaab2d
299 299
300 See also `add-hook', `add-local-hook', and `add-local-one-shot-hook'." 300 See also `add-hook', `add-local-hook', and `add-local-one-shot-hook'."
301 (make-local-hook hook) 301 (make-local-hook hook)
302 (add-one-shot-hook hook function append t)) 302 (add-one-shot-hook hook function append t))
303 303
304 (defun add-to-list (list-var element) 304 (defun add-to-list (list-var element &optional append)
305 "Add to the value of LIST-VAR the element ELEMENT if it isn't there yet. 305 "Add to the value of LIST-VAR the element ELEMENT if it isn't there yet.
306 The test for presence of ELEMENT is done with `equal'. 306 The test for presence of ELEMENT is done with `equal'.
307 If ELEMENT is added, it is added at the beginning of the list,
308 unless the optional argument APPEND is non-nil, in which case
309 ELEMENT is added at the end.
310
307 If you want to use `add-to-list' on a variable that is not defined 311 If you want to use `add-to-list' on a variable that is not defined
308 until a certain package is loaded, you should put the call to `add-to-list' 312 until a certain package is loaded, you should put the call to `add-to-list'
309 into a hook function that will be run only after loading the package. 313 into a hook function that will be run only after loading the package.
310 `eval-after-load' provides one way to do this. In some cases 314 `eval-after-load' provides one way to do this. In some cases
311 other hooks, such as major mode hooks, can do the job." 315 other hooks, such as major mode hooks, can do the job."
312 (or (member element (symbol-value list-var)) 316 (if (member element (symbol-value list-var))
313 (set list-var (cons element (symbol-value list-var))))) 317 (symbol-value list-var)
318 (set list-var
319 (if append
320 (append (symbol-value list-var) (list element))
321 (cons element (symbol-value list-var))))))
314 322
315 ;; XEmacs additions 323 ;; XEmacs additions
316 ;; called by Fkill_buffer() 324 ;; called by Fkill_buffer()
317 (defvar kill-buffer-hook nil 325 (defvar kill-buffer-hook nil
318 "Function or functions to be called when a buffer is killed. 326 "Function or functions to be called when a buffer is killed.