Re: empty permutation true/false

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

On Sun, Feb 25, 2018 at 06:02:44PM +1100, Kevin Ryde wrote:
> I see an empty Vecsmall is true,
> 
>     if(Vecsmall([]), print("yes"), print("no"));
>     => yes
> 
> Is that intended, rely on etc?  I only wondered since an empty full Vec
> is false, per the user manual (just),
> 
>     if([], print("yes"), print("no"));
>     => no
> 
> I have a func where I thought to return a (possibly empty) Vecsmall
> permutation if found, or 0 if not found.  That allows if(perm,...) to do
> something when found/not found -- as long as empty permutation is true.
> Or is some other type of "no such permutation" return usual?

You can do
if(perm===0,...)
if you do not want to depend on that.

Cheers,
Bill.