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* lisp/emacs-lisp/gv.el (gv-ref, gv-deref): New function and macro.

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This commit is contained in:
Stefan Monnier 2012-11-08 08:34:06 -05:00
parent c66f21eaf1
commit d14bb752ea
2 changed files with 22 additions and 0 deletions
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18
lisp/emacs-lisp/gv.el
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@ -433,6 +433,24 @@ The return value is the last VAL in the list.
`(logior (logand ,v ,mask)
(logand ,getter (lognot ,mask))))))))))
;;; References
;;;###autoload
(defmacro gv-ref (place)
"Return a reference to PLACE.
This is like the `&' operator of the C language."
(gv-letplace (getter setter) place
`(cons (lambda () ,getter)
(lambda (gv--val) ,(funcall setter 'gv--val)))))
;;;###autoload
(defsubst gv-deref (ref)
"Dereference REF, returning the referenced value.
This is like the `*' operator of the C language.
REF must have been previously obtained with `gv-ref'."
(declare (gv-setter (lambda (v) `(funcall (cdr ,ref) ,v))))
(funcall (car ref)))
;;; Vaguely related definitions that should be moved elsewhere.
;; (defun alist-get (key alist)