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(add-to-list): Add optional argument APPEND.

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Miles Bader 2000-10-10 02:47:30 +00:00
parent 10e5ab4767
commit c8bfa68964
1 changed files with 8 additions and 3 deletions
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11
lisp/subr.el
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@ -761,10 +761,12 @@ To make a hook variable buffer-local, always use
;; Set the actual variable
(if local (set hook hook-value) (set-default hook hook-value))))
(defun add-to-list (list-var element)
(defun add-to-list (list-var element &optional append)
"Add to the value of LIST-VAR the element ELEMENT if it isn't there yet.
The test for presence of ELEMENT is done with `equal'.
If ELEMENT is added, it is added at the beginning of the list.
If ELEMENT is added, it is added at the beginning of the list,
unless the optional argument APPEND is non-nil, in which case
ELEMENT is added at the end.
If you want to use `add-to-list' on a variable that is not defined
until a certain package is loaded, you should put the call to `add-to-list'
@ -773,7 +775,10 @@ into a hook function that will be run only after loading the package.
other hooks, such as major mode hooks, can do the job."
(if (member element (symbol-value list-var))
(symbol-value list-var)
(set list-var (cons element (symbol-value list-var)))))
(set list-var
(if append
(append (symbol-value list-var) (list element))
(cons element (symbol-value list-var))))))
;;;; Specifying things to do after certain files are loaded.