public static EitherAsync <L, Seq <B> > TraverseSerial <L, A, B>(this Seq <EitherAsync <L, A> > ma, Func <A, B> f)
{
return(new EitherAsync <L, Seq <B> >(Go(ma, f)));
async Task <EitherData <L, Seq <B> > > Go(Seq <EitherAsync <L, A> > ma, Func <A, B> f)
{
var rb = new B[ma.Count];
var ix = 0;
foreach (var a in ma)
{
var mb = await a;
if (mb.IsBottom)
{
return(EitherData.Bottom <L, Seq <B> >());
}
if (mb.IsLeft)
{
return(EitherData.Left <L, Seq <B> >(mb.LeftValue));
}
rb[ix] = f(mb.RightValue);
ix++;
}
return(EitherData.Right <L, Seq <B> >(Seq.FromArray <B>(rb)));
};
}