Re: empty permutation true/false

[Bill Allombert <Bill.Allombert@math.u-bordeaux.fr>]

On Sat, Mar 03, 2018 at 03:15:56PM +1100, Kevin Ryde wrote:
> Bill Allombert <Bill.Allombert@math.u-bordeaux.fr> writes:
> >
> > if(perm===0,...)
> > if you do not want to depend on that.
> 
> That could be ok.  Does it mean don't know yet for == and its friends.

The current semantic is due to the fact that any object 'a' for which 'a-0'
is not valid (i.e. raise an error) is true.

Since
? Vecsmall([])-0
  ***   at top-level: Vecsmall([])-0
  ***                             ^--
  *** _-_: forbidden addition t_INT + t_VECSMALL.

Vecsmall([]) is true

Cheers,
Bill.