> On Wed, Sep 25, 2019 at 3:03 AM Kyotaro Horiguchi <horikyota.ntt@gmail.com> wrote:
>
> At Tue, 24 Sep 2019 09:06:27 -0300, Alvaro Herrera <alvherre@2ndquadrant.com> wrote in
<20190924120627.GA12454@alvherre.pgsql>
> > On 2019-Sep-24, Kyotaro Horiguchi wrote:
> >
> > > Sorry, it's not a boolean. A tristate value. From the definition
> > > (Back, NoMove, Forward) = (-1, 0, 1), (dir1 == -dir2) if
> > > NoMovement did not exist. If it is not guranteed,
> > >
> > > (dir1 != 0 && dir1 == -dir2) ?
> >
> > Maybe just add ScanDirectionIsOpposite(dir1, dir2) with that
> > definition? :-)
>
> Yeah, sounds good to establish it as a part of ScanDirection's
> definition.
Yep, this way looks better.