Re: defining a setter function with gv.el

[Ivan Kanis <ivan.kanis@googlemail.com>]

Stefan Monnier <monnier@iro.umontreal.ca> wrote:

> So I think what you mean is that you want
>
>   (my-function) => tree
>   (setf (my-function) 'shrub)
>   (my-function) => shrub

Yup exactly.

> As for you specific question, I suspect that it is answered in the last
> few lines of gv.el:
>
>    ;;; Vaguely related definitions that should be moved elsewhere.
>    
>    ;; (defun alist-get (key alist)
>    ;;   "Get the value associated to KEY in ALIST."
>    ;;   (declare
>    ;;    (gv-expander
>    ;;     (lambda (do)
>    ;;       (macroexp-let2 macroexp-copyable-p k key
>    ;;         (gv-letplace (getter setter) alist
>    ;;           (macroexp-let2 nil p `(assoc ,k ,getter)
>    ;;             (funcall do `(cdr ,p)
>    ;;                      (lambda (v)
>    ;;                        `(if ,p (setcdr ,p ,v)
>    ;;                           ,(funcall setter
>    ;;                                     `(cons (cons ,k ,v) ,getter)))))))))))
>    ;;   (cdr (assoc key alist)))
>    

Good grief, does it have to be so complicated for such a simple need?
-- 
Ivan Kanis
http://ivan.kanis.fr

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