Re: `max-specpdl-size' and `max-lisp-eval-depth'

[Hongyi Zhao]

On Tue, Sep 28, 2021 at 6:50 PM Stephen Berman <stephen.berman@gmx.net> wrote:
>
> On Sun, 26 Sep 2021 23:01:17 +0800 Hongyi Zhao <hongyi.zhao@gmail.com> wrote:
>
> > On Sun, Sep 26, 2021 at 9:04 PM Eli Zaretskii <eliz@gnu.org> wrote:
> >>
> >> > From: Hongyi Zhao <hongyi.zhao@gmail.com>
> >> > Date: Sun, 26 Sep 2021 19:26:22 +0800
> >> > Cc: help-gnu-emacs <help-gnu-emacs@gnu.org>
> >> >
> >> > what puzzles me most is what is the full English name of the word
> >> > `specpdl'.
> >>
> >> As I recently learned, PDL = push-down list.
> >
> > Thank you for your explanation. Only two built-in symbols in Emacs
> > contain this string in their names - the other is
> > `ar-max-specpdl-size'.
>
> The term goes back to the beginnings of Lisp (McCarthy's paper from
> 1960, available via the Wayback Machine from
> http://www-formal.stanford.edu/jmc/recursive/node4.html):
>
>   In general (we shall discuss an exception), the routine for a
>   recursive function uses itself as a subroutine [...] This possible
>   conflict is resolved by the SAVE and UNSAVE routines that use the
>   public push-down list.
>
> A footnote here (added later) says: "1995: now called a stack"

Cool, thanks!

HZ