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Support COMPARE-FN in add-to-list; thank you Brian Palmer. 2008-02-25 bpalmer <bpalmer@gmail.com> * subr.el(add-to-list): add support for `compare-fn' to sync with emacs.
author Aidan Kehoe <kehoea@parhasard.net>
date Wed, 14 May 2008 23:47:58 +0200
parents ef9eb714f0e4
children 34b42224a066
comparison
equal deleted inserted replaced
4460:04ec3340612e 4461:42fad34efb3f
388 "Add to the local value of HOOK the one-shot function FUNCTION. 388 "Add to the local value of HOOK the one-shot function FUNCTION.
389 You don't need this any more. It's equivalent to specifying the LOCAL 389 You don't need this any more. It's equivalent to specifying the LOCAL
390 argument to `add-one-shot-hook'." 390 argument to `add-one-shot-hook'."
391 (add-one-shot-hook hook function append t)) 391 (add-one-shot-hook hook function append t))
392 392
393 (defun add-to-list (list-var element &optional append) 393 (defun add-to-list (list-var element &optional append compare-fn)
394 "Add to the value of LIST-VAR the element ELEMENT if it isn't there yet. 394 "Add to the value of LIST-VAR the element ELEMENT if it isn't there yet.
395 The test for presence of ELEMENT is done with `equal'. 395 The test for presence of ELEMENT is done with COMPARE-FN; if
396 If ELEMENT is added, it is added at the beginning of the list, 396 COMPARE-FN is nil, then it defaults to `equal'. If ELEMENT is added,
397 unless the optional argument APPEND is non-nil, in which case 397 it is added at the beginning of the list, unless the optional argument
398 ELEMENT is added at the end. 398 APPEND is non-nil, in which case ELEMENT is added at the end.
399 399
400 If you want to use `add-to-list' on a variable that is not defined 400 If you want to use `add-to-list' on a variable that is not defined
401 until a certain package is loaded, you should put the call to `add-to-list' 401 until a certain package is loaded, you should put the call to `add-to-list'
402 into a hook function that will be run only after loading the package. 402 into a hook function that will be run only after loading the package.
403 `eval-after-load' provides one way to do this. In some cases 403 `eval-after-load' provides one way to do this. In some cases
404 other hooks, such as major mode hooks, can do the job." 404 other hooks, such as major mode hooks, can do the job."
405 (if (member element (symbol-value list-var)) 405 (if (if (not compare-fn)
406 (member element (symbol-value list-var))
407 (member* element (symbol-value list-var) :test compare-fn))
406 (symbol-value list-var) 408 (symbol-value list-var)
407 (set list-var 409 (set list-var
408 (if append 410 (if append
409 (append (symbol-value list-var) (list element)) 411 (append (symbol-value list-var) (list element))
410 (cons element (symbol-value list-var)))))) 412 (cons element (symbol-value list-var))))))