Re: Printing an alist of plists with cons format

On Mon, Mar 23, 2026 at 9:03 AM Heime <[email protected]> wrote:

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> On Tuesday, March 24th, 2026 at 12:53 AM, Stéphane Marks <
> [email protected]> wrote:
>
> > On Mon, Mar 23, 2026 at 8:47 AM Heime <[email protected]>
> wrote:
> >
> > >
> > > Have made a two level plist
> > >
> > > (defvar mpl-length
> > >   '(:cm  (:10pt 283.46456 :pt 28.34646 :mm 10 :in 0.39370 :ft 0.03281)
> > >     :in  (:10pt 720 :pt 72 :mm 25.4 :cm 2.54 :ft 0.083333)
> > >     :ft  (:10pt 8640 :pt 864 :mm 304.8 :cm 30.48 :in 12)))
> > >
> > > And wanted to convert it to a different form: making the top-level
> plist
> > > into an alist.
> > >
> > > (defun mpl-plist-to-alist (plist)
> > >   "Convert a nested two-level plist (:u1 plist1 :u2 plist2 ...)
> > > to a plist nested in an alist '((u1 . plist1) (u2 . plist2) ...)."
> > >
> > >   (let (alist)
> > >     (while plist
> > >       (let ((unit   (pop plist))
> > >             (plist  (pop plist)))
> > >         (push (cons unit plist) alist)))
> > >     (nreverse alist)))
> > >
> > >
> > > This gives
> > >
> > > ((:cm :10pt 283.46456 :pt 28.34646 :mm 10 :in 0.3937 :ft 0.03281)
> > >  (:in :10pt 720 :pt 72 :mm 25.4 :cm 2.54 :ft 0.083333)
> > >  (:ft :10pt 8640 :pt 864 :mm 304.8 :cm 30.48 :in 12))
> > >
> >
> > That's a list of lists, not really an alist.  Try improving the code
> above
> > to produce this form:
> >
> > ((:cm (:10pt 283.46456 :pt 28.34646 :mm 10 :in 0.3937 :ft 0.03281))
> >  (:in (:10pt 720 :pt 72 :mm 25.4 :cm 2.54 :ft 0.083333))
> >  (:ft (:10pt 8640 :pt 864 :mm 304.8 :cm 30.48 :in 12)))))
>
> The difficulty seems to stem from (plist (pop plist))
>
> What should I use instead of pop to get the entire plist value?
>

Sorry for misleading, you can use your plain list as an alist.  The car of
each list element is the key.  Do this:

(alist-get :cm '((:cm :10pt 283.46456 :pt 28.34646 :mm 10 :in 0.3937 :ft
0.03281)
                 (:in :10pt 720 :pt 72 :mm 25.4 :cm 2.54 :ft 0.083333)
                 (:ft :10pt 8640 :pt 864 :mm 304.8 :cm 30.48 :in 12)))

(:10pt 283.46456 :pt 28.34646 :mm 10 :in 0.3937 :ft 0.03281)