public static Pair <DiffList <A>, DiffList <B> > Unzip <A, B>(this DiffList <Pair <A, B> > p)
{
return(p.FoldRight <Pair <DiffList <A>, DiffList <B> > >(
(x, y) => (x._1.Get + y._1.Get).And(x._2.Get + y._2.Get)
, DiffList <A> .Empty.And(DiffList <B> .Empty)
));
}
public static DiffList <B> SelectMany <A, B>(this DiffList <A> ps, Func <A, DiffList <B> > f)
{
return(ps.FoldRight((a, b) => f(a) * b, DiffList <B> .Empty));
}
public static DiffList <B> Select <A, B>(this DiffList <A> ps, Func <A, B> f) => ps.FoldRight((a, b) => f(a) + b, DiffList <B> .Empty);