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.
regards.
--
Kyotaro Horiguchi
NTT Open Source Software Center