On Sun, Aug 29, 2021 at 12:57:15PM +0200, Emanuel Berg via Users list for the GNU Emacs text editor wrote:
> tomas wrote:
> 
> >> ;; this file:
> >> ;;   https://dataswamp.org/~incal/scheme/fac.scm
> >> 
> >> (define (fac n)
> >>   (if (> n 1)
> >>       (* n (fac (- n 1)))
> >>     1) )
> >> 
> >> (fac 10) ; 3 628 800
> >
> > That looks for me like a pretty reasonable value for (fac
> > 10). Actually, more reasonable that any other value?
> 
> Yes, but I wrote that. In the video they show another piece of
> code which doesn't work in MIT/GNU Scheme what I can see.

So the difference is (1- n) vs (- n 1)? Why don't you say that,
instead of letting people find out?

Perhaps the function `1-' is just missing in "your" Scheme. You
can have it with

  (def (1- n) (- n 1))

if you want :)

Note: Guile knows about `1-'.

Cheers
 - t