Re: Property list key names

[Lennart Borgman (gmail)]

Juanma Barranquero wrote:
> On Sat, Aug 9, 2008 at 15:56, Lennart Borgman (gmail)
> <address@hidden> wrote:
>
> > I guess there is something like this function in Emacs:
>
> I don't think there's one...
>
> > (defun property-list-keys (plist)
> >  "Return list of key names in property list PLIST."
> >  (let ((keys)
> >        (plist (copy-list plist)))
>
> Why do you copy plist?

Just a mistake.

> >    (while plist
> >      (setq keys (cons (car plist) keys))
> >      (setq plist (cddr plist)))
> >    keys))
>
> > What is the name of it?
>
> It's easy enough to implement, and not much needed (apparently).

Ok, thanks.

> If you're using CL, you can get fancy
>
> (defun  property-list-keys (plist)
>   (let ((c 0))
>     (remove-if #'(lambda (ignore) (zerop (mod (incf c) 2))) plist)))
>
> (not that it is better or clearer than your version, of course ;-)

But I learned something ;-)

>              Juanma